# Bochs User Manual

## Introduction to Bochs

### What is Bochs?

Bochs is a program that simulates a complete Intel x86 computer. It includes emulation of the Intel x86 CPU, common I/O devices, and a custom BIOS. Bochs can be compiled to emulate many different x86 CPUs, from early 386 to the most recent x86-64 Intel and AMD processors which may even not reached the market yet. Bochs interprets every instruction from power-up to reboot, and has device models for all of the standard PC peripherals: keyboard, mouse, VGA card/monitor, disks, timer chips, network card, etc. Because Bochs simulates the whole PC environment, the software running in the simulation "believes" it is running on a real machine. This approach allows Bochs to run a wide variety of software with no modification, include most popular x86 operating systems: Windows 95/98/NT/2000/XP and Vista, all Linux flavors, all BSD flavors, and more.

Bochs is written in the C++ programming language, and is designed to run on many different host platforms

Since Bochs can run on one kind of machine and simulate another machine, we have to be clear in our terminology to avoid confusion. The host platform is the machine that runs the Bochs software. The guest platform is the operating system and applications that Bochs is simulating.

, including x86, PPC, Alpha, Sun, and MIPS. No matter what the host platform is, Bochs still simulates x86 hardware. In other words, it does not depend on the native instructions of the host machine at all. This is both a strength and a weakness, and it's the major difference between Bochs and many other x86 emulation software such as VirtualBox, VMware, etc. Because Bochs uses software simulation for every single x86 instruction, it can simulate a Windows application on an Alpha or Sun workstation. However, the downside of Bochs' approach is simulation performance. To model the processor accurately, Bochs must run many instructions for every simulated x86 instruction, and this makes the simulated machine many times slower than the physical machine. Commercial PC emulators (VMware, Connectix, etc.) can achieve much high emulation speed using a technique called virtualization

Virtualization takes advantage of simulating x86 instructions on an x86 machine, allowing large portions of the simulation to take place at native hardware speed. Whenever the simulated machine talks to the hardware or enters certain privileged modes (such as in kernel code), the simulator typically takes control and simulates that code in software at much slower speed, just like Bochs does.

, but they are neither portable to non-x86 platforms nor open source.

To do anything interesting in the simulated machine, Bochs needs to interact with the operating system on the host platform (the host OS). When you press a key in the Bochs display window, a key event goes into the device model for the keyboard. When the simulated machine needs to read from the simulated hard disk, Bochs reads from a disk image file on the host machine. When the simulated machine sends a network packet to the local network, Bochs uses the host platform's network card to send the packet out into the real world. These interactions between Bochs and the host operating system can be complicated, and in some cases they are host platform specific. Sending a network packet in FreeBSD requires different code than sending the packet in Windows XP, for example. For this reason, certain features are supported on some host platforms and not others. On GNU/Linux, Bochs can simulate a network card that communicates with the world, but on MacOSX the simulated network card may not work because the communication code between the device model and the MacOSX operating system has not been written.

Bochs was written by Kevin Lawton starting in 1994. It started as a program with a commercial license, at the price of 25 USD, for use as-is. If a user needed to link it to other software, that user would have to negotiate a special license. &NEEDHELP;

We need a Bochs historian to help out here. For background, it would be interesting to know how much Bochs sources used to cost and what it was used for. I thought I saw an interview out there somewhere where Kevin says why he started it and some more background information.

Finally, in March 2000, MandrakeSoft (2005 to 2015 called Mandriva) bought Bochs and made it open source under the GNU LGPL. In March 2001, Kevin helped a few developers to move all Bochs activities from bochs.com to a new site at . Since then the Bochs project has settled into its new home, and around release times has even hit #1 most active project of the week at SourceForge.

### Who uses Bochs?

It is hard to estimate how many people have tried Bochs or use it on a regular basis, but a few statistics give an indication. The &devlist;, which is the primary source of news on bugs and releases, has over 400 subscribers. The latest version has been downloaded over 150,000 times from SourceForge, not counting any mirror website or SVN users.

Bochs has many possible uses, and different people use it for different things. Many people use it to run applications in a second operating system without needing two different computers or dual-booting. Running Windows software on a non-x86 workstation or on an x86 Unix box are common uses. Also, because every hardware instruction and every line of simulator code is accessible, Bochs is used extensively for debugging new operating systems. If you were writing boot code for your home-brewed x86 operating system and it didn't work right, booting it in Bochs could give you great visibility into what is really going on. The Bochs debugger lets you simulate quickly or slowly, pausing whenever you want to look at the contents of memory or the CPU registers. Or, if you wanted to study which parts of a program take the most time, you could use Bochs to measure how often certain pieces of the code were executed.

Bochs has been used as a teaching tool in Operating Systems classes, in which students used and modified it to learn how the PC hardware works. As a final project the students had to add a new peripheral device, so they had to learn all about I/O ports, interrupts, and device drivers. In industry, it is used to support legacy applications on modern hardware, and as a reference model when testing new x86-compatible hardware.

There may be as many uses of Bochs as there are users. Do you want to run your old DOS games? Or learn how to program under GNU/Linux, without leaving your Windows desktop? Or reverse engineer your printer driver? You decide.

### Is Bochs right for me?

Bochs is very useful for some applications, and not well suited to others. This section tries to answer the question, "Is Bochs right for me?"

Bochs may or may not be right for you, depending on what it is you want to do. Perhaps all you want to do is run one or two applications native to Microsoft Windows on GNU/Linux, or vice-versa. Perhaps your biggest concern is speed and performance. Maybe you don't mind tweaking a few files here and there when you want another application to work in that setting. In cases where the objective is to simulate x86 hardware on an x86, VirtualBox, Wine, and VMware might be your best options.

On the other hand, perhaps you have a vital application running on an older operating system that only runs well on old hardware. You are concerned that the life cycle of this hardware is coming to an end, and your backup and restoration hardware and tools no longer suffice for the amount of data that you have. You need to transfer backup disk images over a network, and want to use modern procedures for hardware maintenance. Perhaps the application is important enough to run on a larger computer, such as a 64-bit machine, or even a mainframe. Bochs would be an excellent option in such a scenario.

Perhaps your objective is to debug software or hardware drivers. Bochs offers a controlled environment that can better assist you in determining cause and effect relationships. You can take snapshots that show you what is going on behind the scenes. You can isolate the line that caused that crash. You can have multiple images and compare them under a microscope. In this situation, Bochs can save you time and resources.

Information Technology changes faster than any other field. It is very easy to forget transitional software that came and went. But history is important to all fields, and to build on the future, it is important to understand the past. Computer programmers, however, do not have the same advantage as an architect, who can, for example, take a trip to Greece and touch a pillar. Much of the history of Computer Science is left on corroding floppies and malfunctioning hardware. Bochs gives you the benefit of having one or more complete environments where you can understand firsthand the behavior of operating systems and programs. This cannot be achieved with an "emulator" such as Wine.

### Will it work for me?

Whether Bochs works for you depends on your host hardware, host operating system, guest operating system, guest software, and your ability to work in a command-line environment using documentation. There is no wizard to help you through the setup process. You do not get a recovery or installation disk to assist you in the process of installing a guest operating system. Bochs only provides you with the "virtual hardware", and it is up to you to do the rest.

Bochs will run on Windows, GNU/Linux, FreeBSD, OpenBSD, or MacOSX. If you are running on x86 hardware, you have a range of choices. Check the installation section for your host platform to see what options Bochs supports on your platform. If the most important factor is speed, you may want to try a virtualization product instead of Bochs (VMware, VirtualBox, QEMU).

If you are using a non-x86 machine, then Bochs is one of the few choices for running x86 software. Bochs has been known to work on Solaris (Sparc), GNU/Linux (PowerPC/Alpha), MacOS (PowerPC), IRIX (MIPS), Digital Unix (Alpha), and AIX (PowerPC).

You can also find more detailed testing information on the testing status page on the &bochswebsite;.

### Bochs License

Bochs is copyrighted by "The Bochs Project" team and distributed under the GNU Lesser General Public License

Complete text of the GNU LGPL is included with the source code in a file called COPYING, and is also here.

. The following text appears at the top of every source code file released under the LGPL in the Bochs distribution:

Parts of Bochs have specific licenses which are compatible with the GNU Lesser General Public License. Hence each source file contains its own licensing information.

      This library is free software; you can redistribute it and/or
      modify it under the terms of the GNU Lesser General Public
      License as published by the Free Software Foundation; either
      version 2 of the License, or (at your option) any later version.

      This library is distributed in the hope that it will be useful,
      but WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      Lesser General Public License for more details.

      You should have received a copy of the GNU Lesser General Public
      License along with this library; if not, write to the Free Software
      Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

### Third Party Software Licensing and Temporary Files

Before you install or use any Operating System, BIOS, or other software package within the Bochs PC emulation environment, make sure you are and will be in compliance with all the software licenses pertaining to the software you wish to install. It is completely your responsibility to provide licenses and records on all software that you install and/or use. It is also completely your responsibility to maintain total compliance with all software licenses involved.

In the process of installing Software within the Bochs PC emulation environment, it may be helpful or necessary to copy or convert files from the original distribution format to a second format to facilitate the installation. You should delete the intermediate files after installation, making certain that only the original distribution files remain.

### Features

The following table shows the features of Bochs and which platforms they currently work with.

### Bochs Features

Feature | Supported? | Description
configure script | Yes | Bochs uses GNU autoconf to configure Makefiles and headers. Autoconf helps Bochs to compile on a wide variety of platforms.
386,486,Pentium Emulation | Yes | Bochs can be configured to emulate one of several families of Intel hardware. Some Pentium features are incomplete, such as SMM (System Management Mode).
P6 and later CPU Emulation | Yes | Bochs can be configured to emulate any P6 family processor including optional MMX and SSEx instructions.
x86-64 Extensions Emulation | Yes | Bochs can be configured to emulate x86-64 with many recent Intel and AMD extensions.
Command Line Debugger | Yes | Powerful command line debugger (optional) that lets you stop execution and examine registers and memory, set breakpoints, etc.
GUI Debugger | Yes | Chourdakis Michael and Bruce Ewing contributed very powerful GUI frontend for Bochs internal debugger. GUI debugger frontend is supported for Win32 and GTK2/GTK3 hosts.
Floating Point | Yes | Uses software floating point engine based on SoftFloat floating point emulation library.
Enhanced BIOS | Yes | Implements ElTorito, EDD v3.0, basic APM feature, PCIBIOS features and the PCI interrupt routing table. The latest version of the Bochs BIOS has a 32-bit init for ACPI, SMM and SMP. Bochs also known to work with recent SeaBIOS images.
VGA | Yes | VGA color graphics emulation in a window.
VBE (VESA) Support | Yes | Currently resolutions up to 2560x1600x32bpp are supported. You must enable VBE with the VGA extension option and use the LGPL'd VGABIOS. For more information see vesa-notes.
Cirrus Logic video card | Yes | Cirrus Logic CL-GD5430 ISA or CL-GD5446 PCI video card support. For more information see cirrus-notes.
3D video card | Yes | Some of the 3dfx Voodoo graphics adapter models are supported now. The code is still experimental, but at least the Voodoo1 and the Voodoo Banshee PCI are known to work. For more information see voodoo-notes.
Plug&play monitor | Yes | VESA DDC is now supported by all VGA compatible display adapters. The LGPL'd VGABIOS has been updated use this feature for the Bochs VBE, Voodoo Banshee and Cirrus versions. The interface reports a plug&play monitor called "Bochs Screen".
Floppy disk | Yes | Supports floppy disk images on all platforms: 2.88M 3.5", 1.44M 3.5", 1.2M 5.25", 720K 3.5" and 360K 5.25". On Unix and Windows NT/2000/XP, Bochs can access the physical floppy drive. It is also possible to use a local directory as VFAT media (1.44M only).
Multiple ATA channels | Yes | Emulates up to 4 ATA channels. Up to 8 ATA/ATAPI emulated devices can be attached, two per ATA channel. So you can have eight hard disks or seven hard disks and a CD-ROM or four hard disks and four CD-ROMs, or one hard disk and seven CD-ROMs, etc...
Hard disk | Yes | Emulates ATA-6/IDE hard drives via image files. Physical hard disk access is supported on some architecture, but NOT recommended, primarily for safety reasons. With LBA48 support, hard disks up to 255TB are supported, on any platform that support large files access. It is also possible to use a local directory as VFAT drive.
CD-ROM | Yes | Emulates ATAPI-4/IDE CD-ROM. The CD-ROMs can read from an ISO disk image on any platform. On Windows (NT/2000/XP/Vista), Linux, SunOS, FreeBSD, NetBSD, OpenBSD, Amiga/MorphOS and MacOSX, Bochs can read from the physical CD-ROM drive. The Bochs BIOS supports booting from the first CD-ROM drive.
Keyboard | Yes | Emulates a PS/2 keyboard with North American key mappings. Optional keyboard layout remapping files are provided to support localized keyboard in X11 (12 layouts, e.g. French, German, Italian, Russian, Spanish, U.K.) and SDL/SDL2 (German).
Mouse | Yes | Emulates a serial, PS/2, bus or USB mouse with 3 buttons + optional mouse wheel support. There is also a USB tablet emulation available.
Sound card | Yes | Emulates a Sound Blaster 16 card (ISA, no plug&play) or an ES1370 PCI card. The SB16 emulation provides wave input / output, the OPL3 chip, the external MIDI port and volume control for wave and FM. The ES1370 provides wave input / output, the MIDI UART port and volume control for wave output. On Windows, Linux, FreeBSD, MacOS 9, MacOSX and all platforms supported by SDL, the output can be sent to the host computer's sound system. For the SB16, see the developer documentation for details.
Network card | Yes | Emulates an NE2000 compatible network card (ISA / PCI) or an Intel(R) 82540EM Gigabit Ethernet adapter (PCI). On Windows NT/2000, Linux, FreeBSD, and NetBSD, Bochs will forward packets to and from the operating system so that the guest OS can talk on the physical network. Unfortunately, on some platforms the guest OS can talk to any machine on the network BUT NOT the host machine. On Windows and on systems that allow the TAP or TUN/TAP interface, there is no such limitation. Often the host machine may be configured so the guest OS has access to the internet. On MacOSX, you may download the TUN driver from:
Parallel Port | Yes | Parallel port emulation was added by Volker Ruppert for Bochs 1.3. Data that is sent to the parallel port by the guest OS can be saved into a file or sent directly into the parallel port device (Unix only).
Serial Port | Yes | The serial port (16550A UART emulation) is usable, on GNU/Linux, NetBSD, OpenBSD, FreeBSD and MacOSX as host and guest. On other OSes the emulation is present, but the connection to hard- or software of the host is not implemented yet. Up to 4 ports are available.
Gameport | Yes | Emulates a standard PC gameport. The connection to a real joystick is currently supported on Linux and win32 only.
PCI | Yes | Emulates most of the i430FX, i440FX or i440BX PCI chipset. The Host-to-PCI bridge, the PCI-to-ISA bridge and the PCI IDE controller (PIIX3/PIIX4) are available. For PCI cards there are 5 PCI slots supported. ACPI and HPET features are also available. The i440BX chipset has basic support for AGP.
USB | Yes | Four types of host controllers (UHCI, OHCI, EHCI and xHCI) and the devices 'mouse', 'tablet', 'keypad', 'keyboard', 'disk', 'cdrom', 'floppy', 'hub' and 'printer' are available. Plugging in and removing devices at runtime is possible. Access to real hardware is not implemented yet.
Plugins | Yes | Compiling devices, GUI and drivers for network, sound and disk image formats as plugins are supported on Linux, MacOS X, Solaris, Cygwin, MinGW/MSYS, MSVC nmake and the VS2019 IDE (workspace provided).
PIC | Yes | Master and slave programmable interrupt controller.
CMOS functions | Yes | Real time clock (RTC) and CMOS RAM are available
Dynamic Translation/Virtualization | No | Because Bochs is designed to be portable, it does not attempt to do any dynamic code translation or virtualization. See whatisbochs for details.
Simulate a Multiprocessor | Yes | Bochs can be configured to simulate up to 254 processor threads. This feature is still experimental, but it can boot several Linux or Windows guests with SMP support. Please note that this does NOT mean that Bochs can run faster on a physical SMP machine.
Take advantage of your SMP box | Minimal | At present, Bochs only uses threads in some GUIs, in the lowlevel sound output code and in the Voodoo graphics adapter code. The simulation core itself uses only one thread, so it will not run any faster on multiprocessor hardware.
Copy and Paste | Yes | Depending on the host platform, the text-mode screen text can be exported to the clipboard. Text in the clipboard can also be pasted, through Bochs, to the guest OS, as simulated keystrokes.

### Supported Platforms

The following table shows the supported platforms with a small description and the available display libraries on these platforms. The display library is the code that displays the Bochs VGA screen and handles keyboard and mouse events.

### Supported platforms

Platform | Description | Display Libraries
Unix/X11 | X windows has always been well supported because it was Kevin Lawton's main development platform. Bryce Denney maintains the Unix/X11 platform now. Most features and fixes (not all) are tried first in Unix and then ported to the others; see compiling for compile instructions. | x, sdl, sdl2, wx, term, rfb, vncsrv
Win32 | This port was done by David Ross and is now maintained by Don Becker. You can compile with Microsoft Visual C++, see compiling-win32 for compile instructions, or Cygwin, see compile-cygwin. | win32, sdl, sdl2, wx, rfb
MacOS X | Emmanuel Mailliard ported the Macintosh code to MacOS X with Carbon API. Jeremy Parsons (Br'fin) has been maintaining the MacOS X port since March 2002; see compile-macosx for compile instructions. | carbon, x, rfb, sdl, sdl2
PowerPC-Macintosh | David Batterham ported Bochs to the Mac. He compiled with CodeWarrior Pro R1 (CW12) but has not had time to maintain the Mac port since early 2000. If you have Mac development tools and want to contribute, contact the &devlist;; see compile-macos9-codewarrior for compile instructions. | macos
Amiga/MorphOS | This port is written and maintained by Nicholai Benalal, see compile-morphos for compile instructions. | amigaos

### FAQ

Is Bochs Open Source?

Yes! Bochs is released under the GNU LGPL.

How do you pronounce "Bochs"?

Phonetically the same as the English word "box". It's just a play on the word "box", since techies like to call their machines a "Linux box", "Windows box", ... Bochs emulates a box inside a box.

Who is the author of Bochs?

Kevin Lawton is the primary author of Bochs. There have been bug fixes, enhancements, and code contributions from some few hundred people, so it is not possible to list them all. Later, Kevin had been working on a PC virtualization project called plex86. In Fall 2002, he made contributed some major CPU speedups and helped with integration and debugging of the x86-64 emulation code.

Who maintains Bochs now?

With Kevin's help, in April 2001, the members of the &devlist; set up a new official Bochs site hosted by Source Forge. The admins on this project are Greg Alexander, Don Becker, Christophe Bothamy, Bryce Denney, Volker Ruppert and Stanislav Shwartsman.

Tell me about performance when running Bochs.

Because Bochs emulates every x86 instruction and all the devices in a PC system, it does not reach high emulation speeds. Users who have an x86 processor and want the highest emulation speeds may want to consider PC virtualization software such as Vmware or VirtualBox (free software). Another related project is QEMU.

Does Bochs use a disk partition to install the OS?

No. It uses a disk image file, which is simply a large file, like any other file, on your platform's disk.

Why can't I use Bochs with my current WinXP installation?

Think about this. If you had two different PC's, they would require different hardware drivers. So you may not be able to safely move a disk drive with WinXP on it, from one to the other. Bochs is no different. It emulates a certain set of hardware devices, and requires each OS be configured for those devices.

Is there a developer's email list for Bochs?

Yes. For instructions on joining, refer to mailinglist.

Is there an IRC channel for Bochs?

Yes. You will usually find Bochs developers and users on IRC at irc.freenode.net:6667, channel #bochs.

Do you know of any snapshots of Bochs running Windows?

Yes! Look for "Screen Shots" on &bochs-sf-net; or on other Bochs sites.

Does Bochs support a CD-ROM?

Yes, the CD-ROM emulation and accessing ISO files is always available. Reading from host CD-ROM media is supported in Linux, Windows, and most BSDs. The CD-ROM drivers for Bochs allow the guest operating system to access the host operating system's CD-ROM data directly.

Does Bochs support a sound device?

Yes, Bochs emulates a Sound Blaster 16 card (ISA, no plug&play) or an ES1370 PCI. Output to the host sound system is implemented for some platforms. See features for details.

Does Bochs support a network card?

Yes. Bochs emulates an NE2000 compatible network card (ISA / PCI) or an Intel(R) 82540EM Gigabit Ethernet adapter (PCI). Using the host's network capabilities is not supported on all platforms. See features for details.

What applications are known to run inside of Bochs?

Well, lots of different OS's run inside of Bochs, so thousands. I'm assuming you are asking about Windows programs. To give you a few, the following ones from the Winstone'98 tests worked: Access 97, CorelDRAW! 7, Excel 97, Lotus 1-2-3 97, Word 97, PowerPoint 97, Quattro Pro 7, WordPerfect 7.

Also, I've compiled an entire OS kernel inside Bochs before. Not to mention, running DOOM, though at then-pathetic speeds.

I am new to Bochs, how do I start?

You should read setup first. Next, you can check guests if they are specific instructions on how to install your (guest) OS inside of Bochs.

Does Bochs run on my mobile device?

Bochs has now minimal support for the Android platform using a special version of the SDL library. There are some external projects that use the offical sources with some modifications. They also offer a GUI for easy Bochs configuration. Other mobile platforms are not officially supported yet.

## Release Notes

The change log is stored in the Bochs source code in a file called CHANGES. Click here to see the latest version of the CHANGES file.

The link above is provided by Source Forge and might change one day. If it stops working, you can download the current source code with SVN and read the CHANGES file there.

## Installation

### Downloading Bochs

You can download Bochs from our web site at &bochs-sf-net;. First, you need to choose what version to get: a recent release or a development version. If you trying to get things working for the first time, a release version is recommended since it has been tested the most. The development versions (sometimes called SVN snapshots) may have some newer bug fixes and new features, but have not been tested as much as the releases.

Second, you can choose to compile Bochs from source code or install a binary (if one is available for your platform). Binary packages will be quicker to install, and most include a small demo of a guest operating system called DLX Linux to get you started. However, some features can only be enabled if you compile Bochs yourself, for example the Bochs debugger. For multiuser systems, you will probably need system administrator privileges (root) to install a binary package. If you decide to get a binary, download it to your hard disk, uncompress it, then go to the section called Installing a Binary for more information.

If you are going to compile Bochs yourself, you need the gzipped tarball containing the source code, called `bochs-`version`.tar.gz`. For Windows and Mac, the prebuilt Makefiles are separate, so also get the Makefiles for your platform. To unpack a compressed TAR file

A TAR file is a single file that contains many files packed inside. Bochs TAR files are compressed with a program called gzip, and another program called gunzip is used to uncompress them.

on a Unix machine

On Windows, look for software called WinZip to unpack the TAR.

, type

      gunzip -c bochs-version.tar.gz | tar -xvf -

This creates a directory called `bochs-`version`` full of files. This directory will be referred to as &bochsdir;. Go into &bochsdir; and you are ready to compile. Instructions for compiling Bochs are in the section, Compiling Bochs.

Alternatively, you can also obtain the sources for any Bochs version using SVN. See the SVN instructions for details.

### Tracking the source code with SVN

SVN (Subversion) is a tool used by many software developers to manage changes within their source code tree. SVN provides the means to store not only the current version of a piece of source code, but a record of all changes (and who made those changes) that have occurred to that source code. Use of SVN is particularly common on projects with multiple developers, since SVN ensures changes made by one developer are not accidentally removed when another developer posts their changes to the source tree. The Bochs source code and documentation is available using SVN

You can download SVN software and documentation from subversion.apache.org.

.

#### Checking out Bochs

When you have SVN installed, the first step is to do a checkout. The initial checkout command is long and ugly, but usually you only have to do it once. The example below shows the SVN checkout process of the Bochs trunk in Unix. On the Windows platform, you can download a SVN client from subversion.apache.org, or use SVN within Cygwin

Cygwin is an open source Unix-like environment for Windows platforms, available at www.cygwin.com.

.

##### Checking out Bochs in SVN

      user$ svn co http://svn.code.sf.net/p/bochs/code/trunk/bochs bochs
      A    bochs/ltdl.c
      A    bochs/Makefile.in
      A    bochs/bochs.h
      .
      .   (This might take a few minutes, depending on your network connection.)
      .
      A    bochs/install.sh
       U   bochs
      Checkout, Revision 10754.
      user$ cd bochs
      user$ ls
      aclocal.m4       cpu                 logio.cc        pc_system.cc
      bios             cpudb.h             ltdl.c          pc_system.h
      bochs.h          crc.cc              ltdlconf.h.in   plugin.cc
      build            disasm              ltdl.h          plugin.h
      bx_debug         doc                 ltmain.sh       README
      bxversion.h.in   docs-html           main.cc         README-plugins
      bxversion.rc.in  extplugin.h         Makefile.in     README.rfb
      CHANGES          fpu                 memory          README-wxWindows
      config.cc        gdbstub.cc          misc            TESTFORM.txt
      config.guess     gui                 msrs.def        TODO
      config.h.in      host                osdep.cc        win32_enh_dbg.rc
      config.sub       install-sh          osdep.h         win32res.rc
      configure        instrument          param_names.h   wxbochs.rc
      configure.in     iodev               PARAM_TREE.txt
      COPYING          load32bitOShack.cc  patches
      user$ _

This is just an example output of a checkout of specific version of the Bochs trunk and folder. Depending on the checkout command and revision, you most likely will see more/other files.

If you have write access to the Bochs SVN tree, see the Developers Guide

See the Developers Guide and/or look at SourceForge's Subversion documentation, for instructions.

for details.

The SVN checkout process (above) gives you a directory called `bochs` that contains the very latest source code. I will refer to this directory as &bochsdir;. In this directory there's also a subdirectory called ".svn" which tells the SVN software where the code was checked out, what version you have, and where to go for future updates.

#### Getting the Latest Version

Most developers use SVN to always give them the latest source code. The minute that any developer checks in a change, they are available to everyone else through SVN. You just have to type `svn update` in the &bochsdir; directory, and SVN will retrieve any files and directories that have been changed since you did a checkout. If you update regularly, each update takes a short time because it downloads only the files that changed. See also Getting a release version.

The `svn update` command tells you if any new files have been downloaded from the server, and it also tells you if you have modified any of the SVN-controlled files. As it checks through the source directories, it will list files that have changed, with a single letter before the name that tells the status of that file. The most common status letters are listed below.

#### Status letters in a SVN update

Letter | Meaning | Description
? | unknown | This file is in your Bochs directory, but SVN does not know anything about it. For example, when you compile Bochs, any files created during the build process appear as ?.
U | update | SVN downloaded a new version of this file because it changed on the server, usually because someone else did a checkin.
A | added | SVN downloaded a newly added file from the server.
D | deleted | This file has been deleted on the server and SVN removed it from your local copy.
C | conflict | You have changed this file on your disk, but this change conflicts with a change that was checked in. Conflicts occur when two people change the same line of code in different ways. You need to edit the conflicting file(s) and clean it up by hand. Or, sometimes it's easiest to discard your own edits and download a fresh copy, by deleting the conflicting file and running svn update again.

#### Getting a Release Version

You can also use the SVN checkout command to get the Bochs source code for any release since March 2000. The command is

      user$ svn co http://svn.code.sf.net/p/bochs/code/tags/tagname/bochs bochs

The `tagname` tells which release you want, and it can be one of the following:

#### Bochs Release Tags

Bochs version | Release tag for SVN | SVN revision
2.7 | REL_2_7_FINAL | 14332
2.6.11 (bugfix) | REL_2_6_11_FINAL | 13774
2.6.10 (intermediate) | REL_2_6_10_FINAL | 13629
2.6.9 (intermediate) | REL_2_6_9_FINAL | 13181
2.6.8 (intermediate) | REL_2_6_8_FINAL | 12740
2.6.7 (intermediate) | REL_2_6_7_FINAL | 12531
2.6.6 (bugfix) | REL_2_6_6_FINAL | 12375
2.6.5 (intermediate) | REL_2_6_5_FINAL | 12349
2.6.2 (bugfix) | REL_2_6_2_FINAL | 11694
2.6.1 (intermediate) | REL_2_6_1_FINAL | 11667
2.6 | REL_2_6_FINAL | 11395
2.5.1 (bugfix) | REL_2_5_1_FINAL | 10946
2.5 | REL_2_5_FINAL | 10801
2.4.6 | REL_2_4_6_FINAL | 10202
2.4.5 | REL_2_4_5_FINAL | 9914
2.4.2 | REL_2_4_2_FINAL | 9568
2.4.1 | REL_2_4_1_FINAL | 9368
2.4 | REL_2_4_FINAL | 9289
2.3.7 | REL_2_3_7_FINAL | 8537
2.3.6 | REL_2_3_6_FINAL | 8111
2.3.5 | REL_2_3_5_FINAL | 7840
2.3 | REL_2_3_FINAL | 7538
2.2.6 (intermediate2) | REL_2_2_6_FINAL | 7060
2.2.5 (intermediate1) | REL_2_2_5_FINAL | 6942
2.2.1 (bugfix1) | REL_2_2_1_FINAL | 6624
2.2 | REL_2_2_FINAL | 6476
2.1.1 (bugfix1) | REL_2_1_1_FINAL | 5560
2.1 | REL_2_1_FINAL | 5441
2.0.2 (bugfix2) | REL_2_0_2_FINAL | 4592
2.0.1 (bugfix1) | REL_2_0_1_FINAL | 4491
2.0 | REL_2_0_FINAL | 4409
1.4.1 (bugfix1) | REL_1_4_1_FINAL | 2513
1.4 | REL_1_4_FINAL | 2235
1.3 | REL_1_3_FINAL | 1705
1.2.1 (bugfix1) | REL_1_2_1_FINAL | 912
1.2 | REL_1_2_FINAL | 797
1.1.2 (bugfix3) | REL_1_1_2_BASE | 510
1.1.1 (bugfix2) | REL_1_1_1_BASE | 57
1.1 (bugfix1) | REL_1_1_BASE | 51
1.0 (bochs-2000_0325a) | REL-bochs-2000-03-25 | 7

#### More about SVN

Entire books have been written on SVN, so there's no sense in duplicating it all here in the Bochs documentation. Some sources of additional information is listed below.

- The subversion.apache.org site has tons of SVN FAQs and documentation.

- A German SVN FAQ is available at University of Muenster.

### Installing a Binary

This section is divided up by platform, since installing a binary package is different on different platforms.

#### Windows

The Bochs binaries for Windows are distributed in an EXE installer package. The Bochs installer can be started like any other Windows program and it brings up the installation wizard. Here you can select the destination folder and the installation options. The wizard installs the files and creates the registry keys, start menu and desktop links.

Previous releases of Bochs were distributed as ZIP packages, too. These packages contained the same set of files as the installer package from the same version.

If you are new to Bochs you should try out the DLX Linux demo distributed with Bochs. The installation wizard has created a link on the desktop if you decided to install the demo. If you doubleclick the icon two windows will appear: one is the Bochs Display window, and the other is text window that is used for the runtime configuration and for log messages if no logfile is specified.

You can find more information on the DLX Linux demo in the next section below the DLX Linux screenshot.

#### Files in Bochs directory (Windows version)

File | Description
bios.bin-1.13.0 | SeaBIOS ROM image
BIOS-bochs-latest | default ROM BIOS image for Bochs
BIOS-bochs-legacy | ROM BIOS image without 32-bit init code
bochsdbg.exe | the main Bochs executable with debugger enabled
bochs.exe | the main Bochs executable
bochs.ico | the Bochs icon (used for links in start menu and on the desktop)
bochsrc-sample.txt | sample Bochs configuration file
bxhub.exe | utility required for the 'socket' networking module
bximage.exe | tool for manipulating disk images
CHANGES.txt | what has changed between versions
COPYING.txt | copy of the LGPL license
lgban.ico | a set of Bochs icons in different sizes
LICENSE.txt | Bochs license information
logo.ico | another set of Bochs icons
niclist.exe | tool to find out the network interface name
penguin.ico | icons for the DLX Linux link
README.txt | the read-me file from the source distribution.
sb16ctrl.exe | tool to control sb16 in Bochs
sb16ctrl.txt | examples of sb16ctrl commands
SeaBIOS-README.txt | README for SeaBIOS ROM image
SeaVGABIOS-README.txt | README for SeaVGABIOS ROM image
slirp.conf | sample config file for the advanced 'slirp' network configuration
vnet.conf | sample config file for the advanced 'vnet' network configuration
TODO.txt | the TODO file from the source distribution.
unbochs.ico | icon for the uninstaller link
uninstall.exe | uninstall program for Bochs (created by the installation wizard)
vgabios-cirrus.bin-1.13.0 | SeaVGABIOS ROM image (for Cirrus adapter)
VGABIOS-elpin-2.40 | VGA BIOS image for Bochs
VGABIOS-elpin-LICENSE.txt | license for VGA BIOS
VGABIOS-lgpl-latest | LGPL'd VGA BIOS image for Bochs
VGABIOS-lgpl-latest-debug | LGPL'd VGA BIOS image for Bochs with debug output to the logfile
VGABIOS-lgpl-latest-cirrus | LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled
VGABIOS-lgpl-latest-cirrus-debug | LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled and debug output to the logfile
VGABIOS-lgpl-latest-banshee | LGPL'd VGA BIOS image for Bochs with the Voodoo Banshee extension enabled
VGABIOS-lgpl-README.txt | readme for the LGPL'd VGA BIOS
dlxlinux\ | directory containing DLX linux sample disk image and configuration files
dlxlinux\bochsrc.bxrc | Bochs configuration file for DLX
dlxlinux/hd10meg.img | disk image file (10 meg)
dlxlinux\readme.txt | description of DLX linux
dlxlinux\run.bat | Run this BAT file to try out DLX Linux inside Bochs!
dlxlinux\testform.txt | Form for reporting success or failure
doc\index.html | a local copy of all Bochs documentation (online copy)
keymaps\*.map | keymap tables (on Windows used for the paste feature only)

#### Linux RPM

RPM stands for "RedHat Package Manager." An RPM is a compressed file containing files to be installed on your system. Many Linux distributions, not just RedHat ones, can install files from an RPM. First, download the Bochs RPM for your architecture to your computer. For example, if you have an Intel-compatible computer, be sure to get the RPM that says "for Linux x86 distributions" or "i386". Once you have the package on your local disk, you should become the root user and install it as follows

Many distributions have their own RPM installer program, often graphical, and they should work ok. It is helpful to be able to see the text output from RPM, so if you use a fancy RPM installer, be sure to find the text output and check that it looks correct.

:

##### Installing an RPM in Linux

      user$ su
      Password:
      root# ls -l bochs-2.5.x86_64.rpm
      -rw-r--r--    1 user     users     2628643 Nov 27 17:20 bochs-2.5.x86_64.rpm
      root# rpm -i bochs-2.5.x86_64.rpm
      root# exit
      user$ _

All RPM installations are done as the root user because they require permission to update system files and directories. If you do not have root access you need to compile Bochs in your home directory.

RPM installation can fail for a few reasons. It will fail if you already have a Bochs package installed. In this case, try upgrading the old package to the new package with `rpm --upgrade NAME.i386.rpm`. Another potential problem is missing RPM dependencies. If you are getting errors about missing files or RPMs, then first you should try to install the RPMs that provide the missing pieces. If that cannot be done, download the source RPM and build a new binary RPM that is appropriate for your platform. The command is `rpmbuild --rebuild NAME.src.rpm`. As a last resort, you can run rpm with the `--nodeps` option to ignore dependencies and install it anyway, but if it is missing important pieces, it may not run properly.

The Bochs RPM installs five new commands and associated manual pages: bochs, bochs-dlx and bximage. First, let's try out the DLX Linux demo by typing `bochs-dlx`.

      user$ bochs-dlx
      ---------------------------------------------------------------
    	      DLX Linux Demo, for Bochs x86 Emulator
      ---------------------------------------------------------------
      Checking for bochs binary...ok
      Checking for DLX linux directory...ok
      Checking for /bin/gzip...ok
      Checking for /usr/users/bryce/.bochsdlx directory...
      ---------------------------------------------------------------
      To run the DLX Linux demo, I need to create a directory called
      /usr/users/bryce/.bochsdlx, and copy some configuration files
      and a 10 megabyte disk image into the directory.
      ---------------------------------------------------------------
      Is that okay? [y/n]
      y
      Copying /usr/share/bochs/dlxlinux/bochsrc.txt -> /usr/users/bryce/.bochsdlx/.
      Copying /usr/share/bochs/dlxlinux/README -> /usr/users/bryce/.bochsdlx/.
      Copying /usr/share/bochs/dlxlinux/testform.txt -> /usr/users/bryce/.bochsdlx/.
      Uncompressing /usr/share/bochs/dlxlinux/hd10meg.img.gz -> /usr/users/bryce/.bochsdlx/hd10meg.img
      Entering /usr/users/bryce/.bochsdlx
      Running bochs
      ========================================================================
    			Bochs x86 Emulator 2.4.6.svn
    		Build from SVN snapshot, after release 2.4.6
                         Compiled on Oct 20 2011 at 19:40:05
      ========================================================================

Then you get a new X11 window containing the VGA display of the simulated machine. First you see the VGA BIOS screen, then Linux uncompresses and boots, and you get a login prompt. Type "root" and ENTER to log in to DLX linux.

##### Screenshot of Bochs running DLX Linux

Booting is complete when you see "dlx login:" and a cursor. At this login prompt, type "root". On UNIX systems, root is the system admin user. There is no password for root on this sample disk image, so it lets you log in without typing any password. Now you should see a UNIX prompt, and you can begin to type UNIX commands.

      Welcome to DLX V1.0 (C) 1995-96 Erich Boehm
                          (C) 1995    Hannes Boehm

      dlx login: root
      Linux 1.3.89.
      dlx:~# pwd
      /root
      dlx:~# cd /
      dlx:~# ls
      bin/       etc/       lost+found/       root/       usr/
      boot/      fd/        mnt/              sbin/       var/
      dev/       lib/       proc/             tmp/        zip/
      dlx:/# df
      Filesystem    1024-blocks   Used  Available Capacity Mounted on
      /dev/hda1        10060      2736      6005     29%   /
      dlx:/# _

When you get tired of playing with DLX Linux, just type "reboot" in the Bochs window to shut down the DLX Linux operating system, and when it starts to reboot again press the "Power" button at the top of the Bochs display to end the application.

Here is a list of the files that are installed by the RPM, and a brief description of each one.

#### Files in RPM package

File | Description
/usr/bin/bochs | the main Bochs executable
/usr/bin/bochs-dlx | run this script to try out DLX Linux inside Bochs!
/usr/bin/bxhub | utility required for the 'socket' networking module
/usr/bin/bximage | tool for manipulating disk images
/usr/lib/bochs/plugins/* | plugins (devices, guis, etc.) for Bochs (plugin version only)
/usr/share/doc/bochs/bochsrc-sample.txt | sample Bochs configuration file
/usr/share/man/man1/* | man pages for bochs, bochs-dlx and bximage
/usr/share/man/man5/* | man page for bochsrc
/usr/share/doc/bochs/CHANGES | what has changed between versions
/usr/share/doc/bochs/COPYING | copy of the LGPL license
/usr/share/doc/bochs/LICENSE | Bochs license information
/usr/share/doc/bochs/README | the read-me file from the source distribution.
/usr/share/doc/bochs/TODO | the TODO file from the source distribution.
/usr/share/doc/bochs/index.html | a local copy of all Bochs documentation ( Online copy )
/usr/share/doc/bochs/slirp.conf | sample config file for the advanced 'slirp' network configuration
/usr/share/doc/bochs/vnet.conf | sample config file for the advanced 'vnet' network configuration
/usr/share/bochs/BIOS-bochs-latest | default ROM BIOS image for Bochs
/usr/share/bochs/BIOS-bochs-legacy | ROM BIOS image without 32-bit init code
/usr/share/bochs/SeaBIOS-README | README for SeaBIOS ROM image
/usr/share/bochs/SeaVGABIOS-README | README for SeaVGABIOS ROM image
/usr/share/bochs/VGABIOS-elpin-2.40 | VGA BIOS image for Bochs
/usr/share/bochs/VGABIOS-elpin-LICENSE | license for VGA BIOS
/usr/share/bochs/VGABIOS-lgpl-latest | LGPL'd VGA BIOS image for Bochs
/usr/share/bochs/VGABIOS-lgpl-latest-debug | LGPL'd VGA BIOS image for Bochs with debug output to the logfile
/usr/share/bochs/VGABIOS-lgpl-latest-cirrus | LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled
/usr/share/bochs/VGABIOS-lgpl-latest-cirrus-debug | LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled and debug output to the logfile
/usr/share/bochs/VGABIOS-lgpl-latest-banshee | LGPL'd VGA BIOS image for Bochs with the Voodoo Banshee extension enabled
/usr/share/bochs/VGABIOS-lgpl-README | readme for the LGPL'd VGA BIOS
/usr/share/bochs/bios.bin-1.13.0 | SeaBIOS ROM image
/usr/share/bochs/dlxlinux/ | directory containing DLX linux sample disk image and configuration files
/usr/share/bochs/dlxlinux/readme.txt | description of DLX linux
/usr/share/bochs/keymaps/*.map | keymap tables for X11, SDL and SDL2
/usr/share/bochs/vgabios-cirrus.bin-1.13.0 | SeaVGABIOS ROM image (for Cirrus adapter)

#### MacOS X DMG

This was contributed by Aard Vark in January 2003

The MacOS X binary distribution is a mountable disk image (.dmg file). Once you've downloaded the binary distribution file, just double click on it to automatically unpack the archive and mount the volume on the desktop. An icon will appear exactly as if you'd inserted a CD-ROM or removable storage device, and a finder window containing the volume should automatically open. It is likely to have an odd name such as _dmg_top, but don't worry about that.

Copy the Bochs-2.0 (or whatever version) folder from the disk image onto your hard disk. Either Home or Applications would be sensible places to put it. Because the disk image is mounted read only, you can't run the included dlxlinux guest OS until you've copied it to the hard disk.

Once you've installed the binaries, it's probably a good idea to drag the _dmg_top volume to trash to unmount it, so you don't get confused and try to run Bochs from there. Then open the Bochs folder from wherever you installed it.

The MacOS X version of Bochs requires a terminal window to run. If you just double click on the Bochs icon, you'll get an error message telling you to double click on "bochs.scpt" to start Bochs in a new terminal window. You'll need to configure Bochs before you will get very far with the bochs.scpt in the top folder, so to try out Bochs open the dlxlinux folder and double click on the bochs.scpt icon inside.

This will open a new terminal window which will contain the Bochs startup messages, and a configuration menu. The default option is [5], which starts the simulation, so press enter to do so. You will then get a new window containing the VGA display of the simulated machine. The new window will probably appear behind the current terminal window, so either click on the Bochs icon in the dock or the simulation window to bring it to the front. If you're quick enough you'll then see the VGA BIOS screen, then Linux uncompresses and boots, and you get a login prompt. Type "root" and ENTER to log in to DLX Linux.

Once you've finished playing with DLX Linux, just type "reboot" in the Bochs window to shut down the DLX Linux operating system, and when it starts to reboot again press the "Power" button in the "MacBochs Hardware Controls" window (it's the circle containing a vertical bar at the far right - have a look at the Linux screenshots, since the Mac version doesn't seem to have descriptions or tool-tips).

### Compiling Bochs

#### Standard Compile

Bochs is written in C++, so you need a C++ compiler on your system. Most platforms have been tested with GNU gcc/g++, but other compilers are known to work too. By now, you should have unpacked your source TAR file or checked out Bochs from SVN. If not, you can return to Downloading Bochs for details. The top level directory of the source code will be referred to as &bochsdir;. (&bochsdir; contains the files `bochs.h` and `main.cc` and subdirectories `cpu` and `bios`.)

The standard compile process has three basic steps: `configure`, `make`, and `make install`. Each step is described in a separate section below. The standard compile process is used on all Unix machines, MacOS X, and Cygwin (win32). There are separate instructions for compiling for Win32 with Microsoft VC++.

##### Configure

There is a script called `configure` which tests your machine, C/C++ compiler and libraries to discover what settings should work on your system. If you run `configure` with no arguments after it, defaults will be used for all settings. To change the settings, you can run `configure` with options that override the defaults. You can get a list of valid configure options by typing `configure --help`. One useful configure option is --prefix=`directory`, which sets the directory in which Bochs will be installed. All the possible configure options are documented in a later section.

Among other things, the configure script tries to detect your platform and which compile options to use. If you want to control this, set these environment variables before running configure: `CC`, `CXX`, `CFLAGS`, `CXXFLAGS`. Here is an example that sets the environment variables, using bash/ksh

The syntax for bash and ksh is given. In csh and variants, use the syntax `setenv `VARIABLE` `value`` to change environment variables. Do not use an equal sign for csh!

syntax:

      export CC=egcs
      export CXX="$CC"
      export CFLAGS="-Wall -O2 -m486 -fomit-frame-pointer -pipe"
      export CXXFLAGS="$CFLAGS"

Once the configure script knows what options are selected, it creates a Makefile in every source code directory, and creates `$BOCHS/config.h` with all the option values written as preprocessor #defines. Now the sources are ready to compile.

###### Configure Shortcut Scripts

In the Bochs source directory, you will see a series of scripts called `.conf.`platform``. These scripts run the `configure` script for you, with a set of options that are appropriate for that platform. It is not necessary to use the shortcut scripts; they are simply there to show you an example that the developers have used. Some of these scripts have been used to build official binary packages.

If a shortcut script is "almost right" for you, just edit it and then run it! If you run a shortcut script, you don't need to run configure manually.

Run a shortcut script using Bourne shell, like this:

      sh .conf.win32-vcpp

These `.conf.`platform`` scripts have been tested in recent Bochs versions:

###### Shortcut scripts

Name | Build environment
.conf.linux | Linux (32/64 bit)
.conf.macosx | MacOS X
.conf.win32-cygwin | Windows with Cygwin or MinGW/MSYS
.conf.win32-vcpp | Windows with MSVC (32 bit)
.conf.win64-vcpp | Windows with MSVC (64 bit)
.conf.win64-cross-mingw32 | Cross compiling on Linux for Windows

##### Make

The `make` command compiles Bochs. Make is a program used by many software projects that reads the &Makefile; in each source directory and follows the instructions that it finds there. A &Makefile; tells which files depend on which other files, what commands to use to compile and link the code, and more. After you have finished the configure step, just type `make` to build the source code.

The reason that Make is so popular is that it is smart about when to compile and when not to compile. If you run make once, it compiles every file. But when you run it again, it checks to see if any source files have been modified; if not, there's nothing to do! For example, the &Makefile; says that `main.o` depends on `main.cc`. Knowing this, it will only compile `main.cc` if it is newer than `main.o`.

Of course, make can only do the right thing if the &Makefile; lists all the dependencies correctly, so human error can sometimes lead make astray. If make refuses to build something that you think it should, or you are getting strange compile errors, try doing `make all-clean` and then `make` again. All-clean means to clean up the compiled files in every subdirectory, while `make clean` means to clean up just the current directory

This is different from the terminology of some other projects, and it may cause confusion. Sometimes "clean" implies that all subdirectories are affected.

. However, it's important to note that `make all-clean` leaves the configuration intact. You do not have to run `configure` again.

If you're really in the mood for cleaning, `make dist-clean` erases all the configuration information too. In theory, after a dist-clean your directory should look much like when you first untarred it or checked it out. There's usually some extra stuff lying around, but the &Makefile; tries at least to erase any files that it created.

##### Make Install

Once the program has been built, the next step is typically to run `make install` to copy the executables, documentation, and other required files into a public place so that all users can use it. By default, the files are copied to some directories in /usr/local. The following tables show the directories and their contents.

##### Installed files

bin | binary executables (bochs, bximage)
lib/bochs/plugins | plugins (if present)
man/man1 | manpages for installed binaries
man/man5 | manpage for the config file (bochsrc)
share/bochs | BIOS images, VGABIOS images, keymaps
share/doc/bochs | HTML docs, license, readme, changes, bochsrc sample

##### Installing the DLX Linux demo

To download and install the DLX Linux demo distributed with Bochs binary release packages, use these two `make` commands:

      make unpack_dlx
      make install_dlx

The package will be downloaded from the Bochs website and installed at same location as the files of the Bochs base system.

#### Configure Options

This section describes the configure options for Bochs. Perhaps the most important option is `--help`, since it gives you a list of all the other options. The configure script will detect your platform and choose the default GUI for your platform. If the default choice is not what you want, use the `--with-*` options to override the default. The options in the first table tell which GUI library is the default for each platform. Starting in version 2.0, you can use multiple `--with-*` options at once to compile with multiple display libraries, and then choose between them at runtime with the display_library option in the configuration file. Or, you can let the configure script detect which libraries are on your system and use them all, by configuring with `--with-all-libs`.

The concept of platform detection and default GUIs was added in Bochs 1.4. In Bochs 1.3 and before, the X11 GUI was always the default.

#### Defaults by Platform

Platform | Default GUI | Extra compile flags
win32, Cygwin or MinGW/MSYS | --with-win32 | If using nmake method, compile using cl /nologo /MT /W3 /EHs-c- /DNDEBUG /DWIN32 /D_WINDOWS /D_CRT_SECURE_NO_WARNINGS. If using Visual C++ workspace, see the workspace file for compile settings. See Compiling on Win32 with Microsoft VC++ for instructions.
MacOS X or Darwin | --with-carbon | -fpascal-strings -fno-common -arch ppc -Wno-four-char-constants -Wno-unknown-pragmas -Dmacintosh
MacOS 9 or before | --with-macos | none
AmigaOS | --with-amigaos | none
any other platform | --with-x11 | none

#### Configure Options to Select the Display Library (optional)

Option | Comments
--with-x11 | Use X windows user interface. On many operating systems, Bochs will use X windows by default.
--with-win32 | Use the native Win32 GUI. This is the default on win32 platforms.
--with-carbon | Compile for MacOS X with the Carbon GUI. See the .conf.macosx file for the correct MacOS X compile options. WARNING: This Bochs feature is not maintained yet and may fail.
--with-amigaos | Compile for Amiga MorphOS. This code is written by Nicholai Benalal.
--with-rfb | Enable support for the RFB protocol to talk to AT&T's VNC Viewer. Refer to compile-rfb for details.
--with-vncsrv | Enable support for an extended RFB(VNC) GUI using the LibVNCServer library. Refer to compile-vncsrv for details.
--with-sdl | Enable support for the SDL 1.2.x GUI interface; see compile-sdl.
--with-sdl2 | Enable support for the SDL 2.x GUI interface; see compile-sdl2.
--with-term | Use text-only GUI with curses library. Almost certainly won't work right with the debugger or the textconfig interface.
--with-macos | Use Macintosh/CodeWarrior environment. This is for running configure on a platform which supports running configure, so that you may then transfer the configured code over to the real compile environment. WARNING: This Bochs feature is not maintained yet and may fail.
--with-wx | Enable support for wxWidgets configuration and display interface; see compile-wx.
--with-nogui | No native GUI; just use blank stubs. This is if you don't care about having video output, but are just running tests.
--with-all-libs | Automatically detect which libraries are installed on your system and enable them. This option is still experimental; it might enable libraries that are not usable and cause the compile to fail. If you have trouble, just list the `--with-*` options for the specific display libraries that you want.

The remaining options can generally be used with any GUI. For each option such as `--enable-cdrom`, you can also write `--disable-cdrom` to explicitly turn it off. The following 3 tables show the general options (.e.g debugger and plugins support), the CPU-related stuff (e.g. cpu level, SMP, x86_64 support) and the devices options (e.g. PCI, USB, Cirrus graphics).

#### Configure Options (General)

Option | Default | Comments
--enable-plugins | no | Plugins are shared libraries that can be loaded on demand. Example: the serial device is implemented as a plugin. In Unix, the serial plugin is called libbx_serial.so. When Bochs reads its configuration file, if the serial device is enabled it loads libbx_serial.so. See the Features section for supported platforms.
--enable-debugger | no | Compile in support for Bochs internal command-line debugger. This has nothing to do with x86 hardware debug support. It is a more powerful and non-intrusive native debugger. Enabling this will of course slow down the emulation. You only need this option if you know you need it. After you have run `./configure`, you may want to edit `config.h` to customize the debugger further; see internal-debugger for more information.
--enable-debugger-gui | yes if debugger is on | Enable support for the GUI frontend of the Bochs debugger. This feature is supported on Windows hosts and on hosts with GTK2/GTK3 installed.
--enable-readline | detected by configure | Compile the debugger with the GNU readline library, which gives command line editing and history.
--enable-gdb-stub | no | Enable support for the remote GDB stub. See Using Bochs and the remote GDB stub. NOTE: This feature cannot be used if the Bochs debugger is also enabled. WARNING: This Bochs feature is not maintained yet and may fail.
--enable-docbook | detected | Build the docbook documentation in doc/docbook. The configure script will enable this option automatically if you have a program called docbook2html installed.
--enable-instrumentation=`directory` | no | Compile in support for instrumentation. This allows you to collect instrumentation data from Bochs as it executes code. You have to create your own instrumentation library and define the instrumentation macros (hooks in Bochs) to either call your library functions or not, depending upon whether you want to collect each piece of data.
--enable-xpm | yes | Enables the check for the XPM library. This option is only valid if the x display library is enabled (`--with-x11`).
--enable-show-ips | yes | Enables logging of measured IPS, see the `ips` parameter of the cpu option.
--enable-logging | yes | By default, Bochs generates logfile output that can be configured with bochsrc options and at runtime. Use `--disable-logging` to turn off this feature completely.
--enable-assert-checks | yes if debugger is on | BX_ASSERT event causes a panic on assertion failure if enabled (logging feature must be enabled, too).
--enable-cpp | no | Use .cpp as C++ suffix. Renames all the .cc files to .cpp for use with compilers which want that, like older MS C++ compilers. Don't use this option unless you know you need it.
--enable-idle-hack | no | Enables Roland Mainz's experimental idle code, which is intended to keep Bochs from always using 100% of CPU time. When Bochs is waiting around for an interrupt, the idle code uses a select() loop and some X11 tricks to wait until user input arrives. This is designed to keep Bochs responsive while still yielding to other processes when Bochs is idle. It only works with X11 or term GUI.

#### Configure Options (CPU & Memory)

Option | Default | Comments
--enable-cpu-level={`3,4,5,6`} | 6 | Select which CPU level to emulate. Choices are 3,4,5,6 which mean to target 386, 486, Pentium, or Pentium Pro and later emulation.
--enable-smp | no | Compile in support for SMP simulation. This allows you to boot Linux and maybe other OSes in SMP mode, and Bochs will simulate all the different CPUs and communication between them. Do not expect this option to speed up your simulation! On the contrary, it has to spend extra time simulating the different CPUs (even if they're mostly idle) and the communication between them. Use it to try out an SMP OS if you don't have an SMP machine, or to debug SMP OS drivers. Refer to SMP for more details on SMP in Bochs.
--enable-fpu | yes | If you want to compile Bochs to make use of the FPU emulator written by Stanislav Shwartsman, use this option.
--enable-3dnow | no | 3DNow! instruction set support (incomplete)
--enable-x86-64 | no | Add support for x86-64 instruction set, written by Peter Tattam and Stanislav Shwartsman.
--enable-vmx | no | Intel Virtualization Extensions (VMX) support
--enable-svm | no | AMD SVM (Secure Virtual Machine) extensions emulation support
--enable-avx | no | AVX instructions support
--enable-x86-debugger | no | X86 debugger support. If the software you run in Bochs needs to use the x86 hardware debugging facilities such as DR0..DR7, instruction and data breakpoints etc., then you should use this option. Otherwise don't use it, as it will slow down the emulation.
--enable-monitor-mwait | no | MONITOR/MWAIT instructions support (still experimental)
--enable-alignment-check | yes if cpu level >= 4 | support for alignment check in the CPU and #AC exception
--enable-configurable-msrs | no | support for user configurations of emulated MSR registers (see example in msrs.def)
--enable-long-phy-address | no | support for guest physical address larger than 32 bit
--enable-a20-pin | yes | support for the A20 pin
--enable-large-ramfile | yes | support for guest memory larger than the host supports
--enable-repeat-speedups | no | enable support repeated I/O and memory copy speedups
--enable-fast-function-calls | no | enable support for fast function calls (gcc on x86 only)
--enable-handlers-chaining | no | enable support for handlers chaining optimization
--enable-all-optimizations | no | Turn on the enables for all speed optimizations that the developers believe are safe to use: --enable-repeat-speedups, --enable-fast-function-calls, --enable-handlers-chaining.

#### Configure Options (Devices)

Option | Default | Comments
--enable-cdrom | yes | Enable use of a real CD-ROM/DVD drive. The CD-ROM emulation and the portable ISO image file support are always present. You can use this option to compile in support for accessing the media in your workstation's CD-ROM drive. The supported platforms are Linux, Solaris, FreeBSD, OpenBSD, MacOS X and Windows. For other platforms, a small amount of code specific to your platform must be written.
--enable-sb16 | no | Enable Sound Blaster emulation. The available lowlevel sound interfaces are autodetected. See section Using Sound for supported platforms and more info. This option also enables the standard PC gameport which is a part of the SB16. If you don't want to use it, you might use `--disable-gameport`.
--enable-es1370 | no | Enable ES1370 sound emulation. Just like the SB16 option, the available lowlevel sound interfaces are autodetected and the gameport is turned on.
--enable-gameport | no | Enables the standard PC gameport. This option is only necessary if you want to have a gameport, but no SB16 or ES1370 (see above). The connection to a real joystick is currently supported on Linux and win32 only.
--enable-ne2000 | no | Enable NE2000 network card support. This requires a low-level component to be written for each OS (supported on FreeBSD, OpenBSD, Linux, and Windows 9x/NT/2K/XP). When enabled and configured, the NE2000 device model can talk to any computer on the network EXCEPT FOR the local host. Exception: Under most circumstances, Bochs can talk to the local host on Windows, and in the ethertap interface for Linux.
--enable-pnic | no | Enable PCI pseudo NIC (network card) support.
--enable-e1000 | no | Enable Intel(R) 82540EM Gigabit Ethernet adapter support.
--enable-clgd54xx | no | Enable Cirrus Logic GD54xx (CL-GD5430 ISA or CL-GD5446 PCI) video card support. For more information see cirrus-notes.
--enable-voodoo | no | Enable experimental 3dfx Voodoo Graphics emulation. The Voodoo1 is known to work, the Voodoo2 support is not yet complete, but almost usable. The Banshee / Voodoo3 support is under construction, but basically usable. For more information see voodoo-notes.
--enable-iodebug | yes if debugger is on | Dave Poirier has written an experimental interface to the debugger using I/O ports, so that software running in the guest OS can access features of the debugger. You only want this option if you are developing guest OS code for use in Bochs. In other words, most people don't. Also, it should only be used with `--enable-debugger`. See the developer documentation for details.
--enable-pci | yes | Enable limited i440FX / i430FX / i440BX PCI support. This is still incomplete, but usable.
--enable-pcidev | no | Enable PCI host device mapping support. This requires `--enable-pci` to be set as well as Linux 2.4, 2.6 or 3.x as host. WARNING: This Bochs feature is not maintained yet and may fail.
--enable-usb | no | Enable i440FX / i440BX PCI USB support (UHCI). The host controller with 2-port root hub and 9 USB device types are available.
--enable-usb-ohci | no | Enable USB OHCI support. The host controller with 2-port root hub is available (USB device types: same as UHCI).
--enable-usb-ehci | no | Enable USB EHCI support. The host controller with 6-port root hub is available (USB device types: same as UHCI).
--enable-usb-xhci | no | Enable USB xHCI support. The host controller with 4-port root hub is available (USB device types: same as UHCI).
--enable-raw-serial | no | Enable support for the serial port emulation to access to the host's serial port. This feature is partly implemented for Windows hosts only.

#### Transcript of Successful Compilation

This example shows the output of a compilation and installation on Linux.

      user$ ls -l bochs-2.5.tar.gz
      -rw-r--r-- 1 user   users 4117999 27. Nov 17:14 bochs-2.5.tar.gz
      user$ gunzip -c bochs-2.5.tar.gz | tar -xvf -
      bochs-2.5/
      bochs-2.5/.conf.sparc
      bochs-2.5/build/
      bochs-2.5/build/macosx/
      bochs-2.5/build/macosx/pbdevelopment.plist
      bochs-2.5/build/macosx/make-dmg.sh
        .
        .
        .
      bochs-2.5/memory/memory.cc
      bochs-2.5/memory/misc_mem.cc
      bochs-2.5/memory/Makefile.in
      user$ cd bochs-2.5
      user$ ./configure --enable-cpu-level=6
      checking build system type... x86_64-unknown-linux-gnu
      checking host system type... x86_64-unknown-linux-gnu
      checking target system type... x86_64-unknown-linux-gnu
      checking if you are configuring for another platform... no
      checking for standard CFLAGS on this platform...
      checking for gcc... gcc
        .
        .
        .
      config.status: creating build/win32/nsis/bochs.nsi
      config.status: creating host/linux/pcidev/Makefile
      config.status: creating config.h
      config.status: creating ltdlconf.h
      user$ make
      cd iodev && \
              make  libiodev.a
      make[1]: Entering directory `/home/volker/Archiv/test/bochs-2.5/iodev'
      g++ -c  -I.. -I./.. -I../instrument/stubs -I./../instrument/stubs -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES    devices.cc -o devices.o
      g++ -c  -I.. -I./.. -I../instrument/stubs -I./../instrument/stubs -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES    virt_timer.cc -o virt_timer.o
      g++ -c  -I.. -I./.. -I../instrument/stubs -I./../instrument/stubs -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES    slowdown_timer.cc -o slowdown_timer.o
      g++ -c  -I.. -I./.. -I../instrument/stubs -I./../instrument/stubs -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES    pic.cc -o pic.o
        .
        .
        .
      echo done
      done
      /bin/sh ./libtool --mode=link g++ -o bochs -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES      -DBX_SHARE_PATH='"/usr/local/share/bochs"'  -export-dynamic logio.o main.o config.o load32bitOShack.o pc_system.o osdep.o plugin.o crc.o   \
                      iodev/libiodev.a  cpu/libcpu.a cpu/cpudb/libcpudb.a \
                      memory/libmemory.a gui/libgui.a \
                      disasm/libdisasm.a   \
                      fpu/libfpu.a \
                      -lSM -lICE -lX11 -lXpm -lXrandr   \
                      \
                      \
                      \
                      \
                      -lm
      mkdir .libs
      g++ -o bochs -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES -DBX_SHARE_PATH=\"/usr/local/share/bochs\" logio.o main.o config.o load32bitOShack.o pc_system.o osdep.o plugin.o crc.o -Wl,--export-dynamic  iodev/libiodev.a cpu/libcpu.a cpu/cpudb/libcpudb.a memory/libmemory.a gui/libgui.a disasm/libdisasm.a fpu/libfpu.a -lSM -lICE -lX11 -lXpm -lXrandr -lm
      gcc -c -I. -I./. -Iinstrument/stubs -I./instrument/stubs -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES   ./misc/bximage.c -o misc/bximage.o
      /bin/sh ./libtool --mode=link g++ -o bximage -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES     misc/bximage.o
      g++ -o bximage -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES misc/bximage.o
      gcc -c -I. -I./. -Iinstrument/stubs -I./instrument/stubs -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES   ./misc/bxcommit.c -o misc/bxcommit.o
      /bin/sh ./libtool --mode=link g++ -o bxcommit -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES    misc/bxcommit.o
      g++ -o bxcommit -g -O2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES misc/bxcommit.o
      user$ su
      root# make install
      cd iodev && \
              make  libiodev.a
      make[1]: Entering directory `/home/volker/Archiv/test/bochs-2.5/iodev'
        .
        .
        .
      for i in CHANGES COPYING README TODO; do if test -f $i; then install -m 644 $i /usr/local/share/doc/bochs; else install -m 644 ./$i /usr/local/share/doc/bochs; fi; done
      rm -f /usr/local/share/doc/bochs/README
      cat ./build/linux/README.linux-binary ./README > /usr/local/share/doc/bochs/README
      install -m 644 ./.bochsrc /usr/local/share/doc/bochs/bochsrc-sample.txt
      root# exit
      user$ _

#### Compiling on Win32 with Microsoft VC++

The standard compile uses the configure script, but the Windows platform cannot run the configure script natively. The current solution to this problem is that the Bochs configure script must be run on a different platform that does support shell scripts, with options that cause it to configure for a Win32 platform instead of the native one. Many people have access to a UNIX machine that could run the configure script, or you can use Cygwin or MinGW/MSYS to run the configure script.

Because Bochs depends so much on the configure script, if you are doing much win32 Bochs development, you should consider downloading Cygwin or MinGW/MSYS so that you can run the configure step natively.

.

Download the Bochs sources on a machine that can run shell scripts. Edit the configure shortcut script `.conf.win32-vcpp` if you want to adjust the configure options. Then type these commands in the Bochs source directory:

      sh .conf.win32-vcpp
      make win32_snap

These commands will run the configure step, produce VC++ makefiles and workspace files, and pack it all into a .zip file in the directory above the source directory

If the source directory is `/home/joe/bochs-win32`, the resulting .zip file is in `/home/joe/bochs-win32-msvc-src.zip`.

. The .zip file is all ready to transfer to the target Windows machine to be unzipped and compiled. Or, if you run the sh/make steps in Cygwin, you are already on the target machine so you don't need the .zip file.

When you have the Win32 sources transferred to a Windows machine with VC++, find the workspace file called `bochs.sln` in the folder "vs2013" and load it in VC++. Choose `Project:Set Active Project` and be sure that "bochs" is selected. Then choose `Build:Build bochs.exe`. This will build all the required libraries (iodev, cpu, etc.) and the auxiliary programs `bximage.exe`, `bxhub.exe` and `niclist.exe`.

Using workspaces is easy and intuitive, but there is one caveat. The workspaces come directly out of a ZIP file in `build/win32/vs2013ex-workspace.zip`, and they are not controlled by the configure script. When you compile with certain configure options (e.g. `--with-sdl`) you need to link with additional libraries. For now you must add them to the VC++ workspace by hand. In version 2.0, we have improved the situation considerably by adding #if...#endif around every optional file and including nearly every Bochs source file in the workspace. This solves the problem of having to manually add source files to the workspace when you turn on configure options such as `--enable-debugger`. The problem of adding link libraries remains unresolved.

To compile with the Bochs debugger enabled, add `--enable-debugger` to the configure line in `.conf.win32-vcpp` before running it. No modifications to the workspace are necessary.

An alternative way to compile is to run `nmake.exe` in an MS-DOS window. Instead of using the workspace files, nmake uses the Bochs makefiles that are generated by configure. The nmake method is currently used to build the release binaries.

The `make install` doesn't work with nmake yet. Currently it must be run inside of Cygwin or MinGW/MSYS and requires the environment variable INSTDIR to be set.

#### Compiling on Win32 with Cygwin or MinGW/MSYS

Cygwin is a free Unix-like environment for Windows written by Steve Chamberlain and now maintained by RedHat, Inc. You can download it from www.cygwin.com. Because Cygwin supports the configure script and uses GNU gcc/g++, you can use the standard compile process. The configure script should automatically detect Cygwin and add "-mno-cygwin -DWIN32" to the compiler options. You should get a working Bochs if you just type:

      configure
      make

Optionally, you can use the configure shortcut script for Cygwin, `.conf.win32-cygwin`, instead of running configure directly. If this script is close to what you need, just edit the script and then run it. To use the configure shortcut script and compile in Cygwin, the commands are

      sh .conf.win32-cygwin
      make

To find out the options which are known to work in Cygwin, open the file `.conf.win32-cygwin` in any text editor/viewer and have a look at the end of that file.

When using gcc 4.7 or newer you need to add the switch -mno-ms-bitfields to the CFLAGS, to make sure that hdimage and network structures are packed as expected.

The command make install installs the Bochs files in the directory structure of your build environment. To install Bochs into any desired folder you need to use the install_win32 target. It requires the environment variable INSTDIR to be set.

#### Compiling on MacOS 9 with CodeWarrior

It is possible that this hasn't been tried since 1999. In theory, you run `sh .conf.macos` on a Unix box to build the makefiles and headers, copy the whole thing over to a Mac, and then use CodeWarrior to compile. Since it hasn't been tested in so long, it is quite likely that some work is needed to bring the Mac port up to date.

If you are interested and have the required MacOS development tools, please let us know by contacting the &devlist;. Someone requests a MacOS port almost once a month, but none of the developers know how to help them.

#### Compiling on MacOS X

The port to MacOS X with Carbon API by Emmanuel Mailliard is quite new, and the configure and makefile support was added by Bryce Denney. You will need the compiler and libraries from the development tools CD. Bochs should configure and compile with the Carbon GUI if you simply type:

      configure
      make

Optionally, you can use the configure shortcut script for MacOS X, `.conf.macosx`, instead of running configure directly. If this script is close to what you need, just edit the script and then run it. To use the configure shortcut script and compile, the commands are

      sh .conf.macosx
      make

MacOS X has a special format for an application bundle, which looks like a directory that contains the required resource files and binaries. The Makefile currently creates this application bundle "by hand" using mkdir and copy, which is surely the wrong way to do it. Bryce doesn't know the official way to create an application from a Makefile, so this hack will remain until a real Mac developer helps to clean it up.

On MacOS X the default GUI is the Carbon interface, but you can also try other Bochs GUIs. Use `--with-x11` for X windows, `--with-rfb` for VNC/RFB, `--with-sdl` for SDL or `--with-sdl2` for SDL2.

#### Compiling on Amiga/MorphOS

Nicholai Benalal created this port to MorphOS running on Amiga. It should compile with:

      configure
      make

If the platform is not detected properly, you might need to use `--enable-amigaos` as a configure option. Optionally, you can use the configure shortcut script, `.conf.amigaos`.

#### Compiling with the RFB interface

The RFB code was written by Don Becker x-odus@iname.com, who has a Bochs-RFB web page on his site, http://www.psyon.org/bochs-rfb/.

This interface allows you to view the Bochs display with AT&T's VNC Viewer. The protocol used between a VNC server and a VNC viewer is called RFB. Because the RFB code in Bochs is written with portable network socket and POSIX thread code, it can be compiled on many platforms and has been tested in Linux and Win32. No additional libraries are required. To try it, type:

      configure --with-rfb
      make

RFB currently uses this setup:

- port range 5900 to 5949 (using the first one available)

- no authentification

- by default 30 seconds waiting for client

- 8 bpp (BGR233 / RGB332) supported only

- if client doesn't support resize: desktop size 720x480 (for text mode and standard VGA)

- if resize supported: maximum resolution 1280x1024

With the display library option "timeout" the default value of 30 seconds can be changed. With a value of 0 it is possible to start the simulation without a client connected.

#### Compiling with the VNCSRV interface

The LibVNCServer is a cross-platform library that allows to implement VNC server functionality easily. On platforms supported by LibVNCServer Bochs can be compiled with support for it this way:

      configure --with-vncsrv
      make

Unlike the RFB GUI this new implementation is not limited to 8 bpp and it is possible to connect a Bochs session with a web browser.

#### Compiling with the SDL interface

Dave Poirier has written an SDL interface for Bochs. Simple DirectMedia Layer, or SDL, is a cross-platform multimedia library distributed from libsdl.org. SDL is available for many platforms including Win32, Linux, BSD, IRIX, MacOS, MacOS X, and AmigaOS.

To compile Bochs with SDL, you must first install the SDL library from libsdl.org. You can either get the source code and compile it yourself, or install the development libraries for your platform (already compiled). Then, go into the Bochs directory and type:

      configure --with-sdl
      make

If you are on FreeBSD and have SDL installed using the ports collection, Bochs won't be able to find the library automatically, as the SDL config script is called `sdl11-config` in that case (even for version 1.2). The easiest way to make Bochs find it, is to create a symlink to that script called `sdl-config` inside a directory which is in the path. For example:

      ln -s /usr/local/bin/sdl11-config ~/bin/sdl-config

To compile in Microsoft VS2013Ex, you have to configure on a different system (see Compiling on Win32 with Microsoft VC++). Before running the configure script, you have to add `--with-sdl` to the shortcut script. If you have already configured, you can set `BX_WITH_SDL` to 1 in `config.h`.

Then you have to set up the project for SDL this way:

    - add source file sdl.cc to the module gui
    - add path to the SDL include files to the modules bochs and gui
    - add lbraries SDL.lib and SDLmain.lib to the module bochs
    - change the runtime library for all modules to Multithreaded-DLL (/MD)

Compiling with MSVC `nmake` is not supported yet.

#### Compiling with the SDL version 2 interface

The SDL library version 2 is now also supported by Bochs. For some basic information about SDL, see compile-sdl. The configure option to enable SDL2 support is `--with-sdl2` and the configuration script is called `sdl2-config`. Note that the Bochs GUIs for SDL version 1.2.x and 2.x are mutually exclusive. The legacy SDL GUI support will be removed someday. When using the GUI library autodetection (`--with-all-libs`) the configure script probes for SDL version 2 first.

#### Compiling with the wxWidgets interface

wxWidgets is a cross-platform C++ user interface library which you can download for free at wxwidgets.org. The wxWidgets port of Bochs provides both a graphical configuration interface for editing `bochsrc` options (see config_interface option) and a display (see display_library option). It was written by Bryce Denney, Don Becker, Dave Poirier, and Volker Ruppert.

      configure --with-wx
      make

If you want Bochs to use a wxWidgets installation not in your path (but installed somewhere else), you need to set the WX_CONFIG environment variable to the proper wx-config script, before running configure (example for csh):

      setenv WX_CONFIG '/home/compile/wx/bin/wx-config'

#### Building an RPM on Linux

RPM stands for "RedHat Package Manager." An RPM is a compressed file containing files to be installed on your system. Bochs has a special shell script called `make-rpm` that helps to build an RPM of Bochs. Start with a clean source directory. Edit .conf.linux first if you want to adjust the configure options. Then, type:

      ./build/redhat/make-rpm | tee /tmp/build.txt

When this command completes, you should have a source RPM and a binary RPM of Bochs in the current directory. The `tee` part of the command (optional) saves a transcript of the build process into /tmp/build.txt, which is very useful if anything goes wrong. Instructions for installing an RPM are here.

In the past, you had to build rpms as root, but as of version 2.0 you can build them as a normal user.

#### Compile Problems

##### The configure script failed

The `configure` script can fail for various reasons. If the error message on the shell doesn't give enough information, it is recommended to review the output file `config.log` to find out what exactly happened. The following issues can be fixed by modifying the configure options used:

- deprecated option (option from previous Bochs version not needed / supported anymore)

- mutually exclusive option (e.g. `--enable-debugger` and `--enable-gdb-stub`)

- dependent option (e.g. USB support requires PCI support)

- incomplete option (e.g. `--enable-cpu-level` requires an argument)

- development package for library not installed (e.g. for `--with-wx`)

If the configure issue cannot be fixed by option changes and / or installing development packages / tools it should be reported in the &devlist; or the SF bug tracker for the Bochs project.

##### Make / compilation failure

The `make` utility itself can only fail if the specified target is not supported by the environment or simply doesn't exist. In most cases the programs called from `make` are causing the failure (e.g. compiler / linker).

In some cases it might be useful to rebuild Bochs completely by calling `make dist-clean` and running the `configure` script once again. These steps are recommended if the development sources from SVN are used and one of the build system files (e.g. `Makefile` or `config.h.in`) has been changed.

Sometimes it is possible to isolate the failing piece of code by disabling one or more configure options. For example, if the compilation fails somewhere in the cpu/avx* files, it might help to configure without `--enable-avx`. The same could be done with other Bochs facilities controlled by configure options.

##### Runtime issues with self-compiled Bochs

After a successful compilation the self-compiled Bochs can fail if at least one library is not installed properly. This can happen if the library consists of a development and a runtime package and the second one is missing. Another problem can appear on build environments like Cygwin and MinGW/MSYS. Applications built there are usually designed to be run inside of the environment. When starting them from the Windows shell, it may cause errors like "missing `cygwin1.dll`" or similar. In that case, the missing DLL must be copied from e.g. the Cygwin folder to the location of the compiled EXE file.

## Setup

### What does Bochs need?

These are the minimum requirements for running an OS inside of Bochs:

- the Bochs executable

- the BIOS image (usually called `BIOS-bochs-latest`)

- the VGA BIOS image (e.g. `VGABIOS-lgpl-latest` or `VGABIOS-elpin-2.40`)

- at least one bootable media, either as disk image (floppy, hard disk or CD-ROM) or physical disk (floppy or CD-ROM)

Both VGA BIOS versions as well as the ROM BIOS are part of the Bochs package. No separate download is necessary. See rom-images for more information.

If you want to use the Cirrus SVGA adapter instead of VGA + Bochs VBE, you should have a look at cirrus-notes.

In that case you have to pass the configuration options on the command line or to use the configuration interface to set up Bochs for the simulation. Running Bochs is easier if you use a configuration file (we call it `bochsrc`). See bochsrc for all supported options.

The easiest way to setup Bochs for the first time is to use the example configuration file called `bochsrc-sample.txt`. Locate that file (location depends on the (host) OS and on the installation facility used) and copy it to a location where Bochs looks for that file, see search-order.

The next step is to change the configuration so that it fits your needs: You most likely want to setup a hard disk (see using-bximage and bochsopt-ata-master-slave), and install some OS on it using either a set of floppy disks (see bochsopt-floppyab) or a CD-ROM (see bochsopt-ata-master-slave again) as installation media. Make sure you boot the emulation from the media you want, using the right setting as boot option.

If your keyboard output inside of Bochs is wrong, you may also need a keymap file to remap your keyboard layout to the U.S. layout. A set of keymap files for the X window system and SDL (Linux port) is distributed with Bochs. If your keyboard layout is not supported yet, you can create your own one by following the instructions given in keymap.

A collection of disk images of different operating systems can be found at . Some disk images are the size of a floppy disk (1 meg compressed) and others are gigantic (160 meg compressed). If you want to create a disk image yourself, please see diskimagehowto.

### ROM images

Just like a real PC, Bochs needs a system BIOS and VGA BIOS to initialize the machine when it powers on or after a hardware reset. Bochs needs to load them from image file into the emulated memory. The Bochs package contains a set of system BIOS and VGA BIOS images.

### System and VGA BIOS images

File | Description
BIOS-bochs-latest | default ROM BIOS image for Bochs
BIOS-bochs-legacy | ROM BIOS image without 32-bit init code (for i386 and ISA graphics card emulation)
bios.bin-1.13.0 | SeaBIOS ROM image
VGABIOS-elpin-2.40 | legacy VGA BIOS image for Bochs
VGABIOS-lgpl-latest | LGPL'd VGA BIOS image for Bochs
VGABIOS-lgpl-latest-debug | LGPL'd VGA BIOS image for Bochs with debug output to the logfile
VGABIOS-lgpl-latest-cirrus | LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled
VGABIOS-lgpl-latest-cirrus-debug | LGPL'd VGA BIOS image for Bochs with the Cirrus extension enabled and debug output to the logfile
VGABIOS-lgpl-latest-banshee | LGPL'd VGA BIOS image for Bochs with the Voodoo Banshee extension enabled
vgabios-cirrus.bin-1.13.0 | SeaVGABIOS ROM image (for Cirrus adapter)

Bochs must be set up to use system and VGA BIOS like this:

      romimage: file=BIOS-bochs-latest, address=0xfffe0000
      vgaromimage: file=VGABIOS-lgpl-latest

We recommend to use the ROM images distributed with Bochs or one of the latest SeaBIOS images. BIOS images designed for real hardware mostly do not work properly. Please see the bochsopt-romimage for more information.

Bochs supports optional ROM images to be loaded into the ISA ROM space, typically between C8000 and EFFFF (see bochsopt-optrom). The PCI versions of the Bochs network adapter emulations support loading a boot ROM into the PCI ROM space (see bochsopt-ne2k).

### The configuration file `bochsrc`

Bochs uses a configuration file called `bochsrc` to know where to look for disk images, how the Bochs emulation layer should work, etc. When you first start up Bochs, it looks around for its configuration file (see search-order), and parses it. Here are a few lines from a sample file:

      ata0-master: type=disk, path="30M.sample", cylinders=615, heads=6, spt=17
      boot: disk

The format is very strict, so be sure to put the right number of spaces and use lowercase letters. As you can see, most lines have a keyword telling what is being configured, followed by a colon, followed by a few `property`=`value` pairs, separated by commas. For very simple options, sometimes just a single value is needed. The source and binary distributions come with a sample `bochsrc`, so you can just copy the sample file and edit the settings you need to change.

The syntax used for `bochsrc` can also be used as command line arguments for Bochs. If you have any spaces in your command line arguments, they should be enclosed in single quotes, for example:

      bochs 'boot:floppy' 'floppya: 1_44=a.img, status=inserted'

For other arguments, see section Command line arguments.

You can use environment variables with the dollar sign prefix in the `bochsrc` file, for example:

      floppya: 1_44="$IMAGES/bootdisk.img", status=inserted
      boot: floppy

There are two environment variables with a built-in default value which is set at compile or installation time. $BXSHARE points to the "share" directory which is typically /usr/local/share/bochs on UNIX machines. See the $(sharedir) variable in the Makefile for the exact value. $BXSHARE is used in the config files of the Bochs disk images to locate the directory where the BIOS images and keymaps can be found. If $BXSHARE is not defined, Bochs will supply the default value. Also, $LTDL_LIBRARY_PATH points to a list of directories to search in for Bochs plugins. The paths are separated by colons (on Windows: semicolons). A compile-time default is provided if this variable is not defined by the user. On Win32 and MacOSX, the default for the share directory is determined by a platform-specific specific algorithm. On Win32, we use the registry to see what directory Bochs and its support files were installed in. On MacOSX, the share directory is the directory where the application is located.

You can use the `#include` statement in the bochsrc to read the configuration from other files. Now it is possible to put platform or installation defaults in a global config file (e.g. location of rom images). Put this on top of your config file if the global configuration is stored in /etc:

     #include /etc/bochsrc

Bochs now treats an unknown option as optional device plugin if it exists. It loads this plugin and then it tries to call the parser function for this configuration line which is located in the plugin. This mechanism is implemented for the Bochs network, sound, and USB host controller devices. Externally developed device plugins (AKA "user plugins") now can also be loaded this way.

The section below lists all the supported `bochsrc` options.

#### plugin_ctrl

Example:

      plugin_ctrl: unmapped=0, e1000=1 # unload 'unmapped' and load 'e1000'

Controls the presence of optional device plugins. These plugins are loaded directly with this option and some of them install a config option that is only available when the plugin device is loaded. The value "1" means to load the plugin and "0" will unload it (if loaded before).

These plugins will be loaded by default (if present): 'biosdev', 'extfpuirq', 'gameport', 'iodebug','parallel', 'serial', 'speaker' and 'unmapped'.

These plugins are also supported, but they are usually loaded directly with their bochsrc option: 'e1000', 'es1370', 'ne2k', 'pcidev', 'pcipnic', 'sb16', 'usb_ehci', 'usb_ohci', 'usb_uhci', 'usb_xhci' and 'voodoo'.

Externally developed device plugins (AKA "user plugins") now can also be loaded this way.

#### config_interface

The configuration interface is a series of menus or dialog boxes that allows you to edit all the settings that control Bochs' behavior. Depending on the platform there are up to 3 choices of configuration interface: a text mode version called "textconfig" and two graphical versions called "win32config" and "wx". The text mode version uses stdin/stdout or GUI console (if available / runtime config) and is always compiled in, unless Bochs is compiled for wx only. The choice "win32config" is only available on win32/win64 and it is the default on these platforms. The choice "wx" is only available when Bochs is compiled with wxWidgets support, see compile-wx. If you do not write a config_interface line, Bochs will choose a default for you.

wxWidgets provides both a configuration interface and a display library. So if you use the "wx" configuration interface, you must also use the "wx" display library, see display_library option.

Examples:

      config_interface: textconfig
      config_interface: win32config
      config_interface: wx

#### display_library

The display library is the code that displays the Bochs VGA screen. Bochs has a selection of about 10 different display library implementations for different platforms. If you run configure with multiple `--with-*` options, the display_library option lets you choose which one you want to run with. If you do not use a display_library line, Bochs will choose a default for you.

wxWidgets provides both a configuration interface and a display library. So if you use the "wx" display library, you must also use the "wx" configuration interface, see config_interface option.

Examples:

      display_library: x
      display_library: sdl2, options=fullscreen
      display_library: options=cmdmode

Some display libraries now support specific options to control their behaviour. These options are supported by more than one display library:

      "cmdmode"     - call a headerbar button handler after pressing F7 (sdl, sdl2, win32, x)
      "fullscreen"  - startup in fullscreen mode (sdl, sdl2)
      "gui_debug"   - use GTK debugger GUI (sdl, x) / Win32 debugger GUI (sdl, sdl2, win32)
      "hideIPS"     - disable IPS output in status bar (rfb, sdl, sdl2, term, vncsrv, win32, wx, x)
      "nokeyrepeat" - turn off host keyboard repeat (sdl, sdl2, win32, x)
      "no_gui_console" - use system console instead of builtin GUI console (rfb, sdl, sdl2, vncsrv, x)
      "timeout"     - time (in seconds) to wait for client (rfb, vncsrv)

See the examples below for other currently supported options.

      # "traphotkeys" - system hotkeys not handled by host OS, but sent to guest
      #                 (win32 in mouse capture and fullscreen mode: alt-tab, win,
      #                 alt-space, alt-esc, ctrl-esc)
      # "autoscale"   - scale small simulation window by factor 2, 4 or 8 depending
      #                 on desktop window size
      display_library: win32, options="traphotkeys autoscale"

Setting up options without specifying display library is also supported.

#### display_library values

Option | Description
x | use X windows interface, cross platform
win32 | use native win32 libraries
carbon | use Carbon library (for MacOS X)
macintosh | use MacOS pre-10
amigaos | use native AmigaOS libraries
sdl | use SDL 1.2.x library, cross platform, details in compile-sdl
sdl2 | use SDL 2.x library, cross platform, details in compile-sdl2
term | text only, uses curses/ncurses library, cross platform
rfb | provides an interface to AT&T's VNC viewer, cross platform, details in compile-rfb
vncsrv | use LibVNCServer for extended RFB(VNC) support, details in compile-vncsrv
wx | use wxWidgets library, cross platform, details in compile-wx
nogui | no display at all

#### cpu

Example:

      cpu: count=2, ips=10000000

This defines the parameters of the cpu inside Bochs:

`model`

Selects CPU configuration to emulate from pre-defined list of all supported configurations. When this option is used and the value is different from 'bx_generic', the parameters of the CPUID option have no effect anymore. See the cpu-models for supported values.

`count`

Set the number of processors:cores per processor:threads per core when Bochs is compiled for SMP emulation. Bochs currently supports up to 14 threads (legacy APIC) or 254 threads (xAPIC or higher) running simultaniosly. If Bochs is compiled without SMP support, it won't accept values different from 1. For more information on SMP see SMP.

`quantum`

Maximum amount of instructions allowed to execute by processor before returning control to another cpu. This option exists only in Bochs binary compiled with SMP support.

`reset_on_triple_fault`

Reset the CPU when a triple fault occurs (highly recommended) rather than PANIC. Remember that if you are trying to continue after triple fault the simulation will be completely bogus !

`cpuid_limit_winnt`

Determine whether to limit maximum CPUID function to 2. This mode is required to work around WinNT installation and boot issues.

`mwait_is_nop`

When this option is enabled MWAIT will not put the CPU into a sleep state. This option exists only if Bochs compiled with `--enable-monitor-mwait`.

`msrs`

Define path to user CPU Model Specific Registers (MSRs) specification. See example in msrs.def.

`ignore_bad_msrs`

Ignore MSR references that Bochs does not understand; print a warning message instead of generating #GP exception. This option is enabled by default but will not be available if configurable MSRs are enabled.

`ips`

Emulated Instructions Per Second. This is the number of IPS that Bochs is capable of running on your machine. You can recompile Bochs with `--enable-show-ips` option enabled, to find your workstation's capability. Measured IPS value will then be logged into your log file or in the status bar (if supported by the GUI).

IPS is used to calibrate many time-dependent events within the Bochs simulation. For example, changing IPS affects the frequency of VGA updates, the duration of time before a key starts to autorepeat, and the measurement of BogoMips and other benchmarks. The table below lists some typical IPS settings for different machines

IPS measurements depend on OS and compiler configuration in addition to host processor clock speed.

.

#### Example IPS Settings

Bochs | Speed | Machine/Compiler | Typical IPS
2.4.6 | 3.4Ghz | Intel Core i7 2600 with Win7x64/g++ 4.5.2 | 85 to 95 MIPS
2.3.7 | 3.2Ghz | Intel Core 2 Q9770 with WinXP/g++ 3.4 | 50 to 55 MIPS
2.3.7 | 2.6Ghz | Intel Core 2 Duo with WinXP/g++ 3.4 | 38 to 43 MIPS
2.2.6 | 2.6Ghz | Intel Core 2 Duo with WinXP/g++ 3.4 | 21 to 25 MIPS
2.2.6 | 2.1Ghz | Athlon XP with Linux 2.6/g++ 3.4 | 12 to 15 MIPS

#### cpuid

Example:

      cpuid: level=6, mmx=1, sep=1, sse=sse4_2, apic=xapic, aes=1, movbe=1, xsave=1

This defines features and functionality supported by Bochs emulated CPU. These settings are only valid and configurable if the cpu model is set to the default value 'bx_generic'.

`level`

Set emulated CPU level information returned by CPUID. Default value is determined by configure option --enable-cpu-level. Currently supported values are 5 (for Pentium and similar processors) and 6 (for P6 and later processors).

`family`

Set family information returned by CPUID. Default family value determined by configure option --enable-cpu-level.

`model`

Set model information returned by CPUID. Default model value is 3.

`stepping`

Set stepping information returned by CPUID. Default stepping value is 3.

`vendor_string`

Set the CPUID vendor string returned by CPUID(0x0). This should be a twelve-character ASCII string.

`brand_string`

Set the CPUID brand string returned by CPUID(0x80000002 .. 0x80000004]). This should be at most a forty-eight-character ASCII string.

`mmx`

Select MMX instruction set support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 5.

`apic`

Select APIC configuration (LEGACY/XAPIC/XAPIC_EXT/X2APIC). This option exists only if Bochs compiled with BX_CPU_LEVEL >= 5.

`sep`

Select SYSENTER/SYSEXIT instruction set support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`simd`

Select SIMD instructions support. Any of NONE/SSE/SSE2/SSE3/SSSE3/SSE4_1/SSE4_2/AVX/AVX2/AVX512 could be selected. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6. The AVX choices exists only if Bochs compiled with --enable-avx option.

`sse4a`

Select AMD SSE4A instructions support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`misaligned_sse`

Select AMD Misaligned SSE mode support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`aes`

Select AES instruction set support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`sha`

Select SHA instruction set support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`movbe`

Select MOVBE Intel(R) Atom instruction support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`adx`

Select ADCX/ADOX instructions support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`xsave`

Select XSAVE extensions support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`xsaveopt`

Select XSAVEOPT instruction support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`avx_f16c`

Select AVX float16 convert instructions support. This option exists only if Bochs compiled with `--enable-avx` option.

`avx_fma`

Select AVX fused multiply add (FMA) instructions support. This option exists only if Bochs compiled with `--enable-avx` option.

`bmi`

Select BMI1/BMI2 instructions support. This option exists only if Bochs compiled with `--enable-avx` option.

`fma4`

Select AMD four operand FMA instructions support. This option exists only if Bochs compiled with `--enable-avx` option.

`xop`

Select AMD XOP instructions support. This option exists only if Bochs compiled with `--enable-avx` option.

`tbm`

Select AMD TBM instructions support. This option exists only if Bochs compiled with `--enable-avx` option.

`x86_64`

Enable x86-64 and long mode support. This option exists only if Bochs compiled with x86-64 support.

`1g_pages`

Enable 1G page size support in long mode. This option exists only if Bochs compiled with x86-64 support.

`pcid`

Enable Process-Context Identifiers (PCID) support in long mode. This option exists only if Bochs compiled with x86-64 support.

`smep`

Enable Supervisor Mode Execution Protection (SMEP) support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`smap`

Enable Supervisor Mode Access Prevention (SMAP) support. This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

`mwait`

Select MONITOR/MWAIT instructions support. This option exists only if Bochs compiled with `--enable-monitor-mwait`.

`vmx`

Select VMX extensions emulation support. This option exists only if Bochs compiled with `--enable-vmx` option.

`svm`

Select AMD SVM (Secure Virtual Machine) extensions emulation support. This option exists only if Bochs compiled with `--enable-svm` option.

#### memory

Examples:

      memory: guest=512, host=256

Set the amount of physical memory you want to emulate.

`guest`

Set amount of guest physical memory to emulate. The default is 32MB, the maximum amount limited only by physical address space limitations.

`host`

Set amount of host memory you want to allocate for guest RAM emulation. It is possible to allocate less memory than you want to emulate in guest system. This will fake guest to see the non-existing memory. Once guest system touches new memory block it will be dynamically taken from the memory pool. You will be warned (by FATAL PANIC) in case guest already used all allocated host memory and wants more.

Due to limitations in the host OS, Bochs fails to allocate more than 1024MB on most 32-bit systems. In order to overcome this problem, configure and build Bochs with `--enable-large-ramfile` option.

#### megs

Examples:

      megs: 32
      megs: 128

This option sets the 'guest' and 'host' memory parameters to the same value. In all other cases the 'memory' option should be used instead.

#### romimage

Examples:

      romimage: file=bios/BIOS-bochs-latest, options=fastboot
      romimage: file=$BXSHARE/BIOS-bochs-legacy
      romimage: file=asus_p6np5.bin, flash_data=escd.bin
      romimage: file=mybios.bin, address=0xfff80000

The ROM BIOS controls what the PC does when it first powers on. Normally, you can use a precompiled BIOS in the source or binary distribution called `BIOS-bochs-latest`. The default ROM BIOS is usually loaded starting at address 0xfffe0000, and it is exactly 128k long. The legacy version of the Bochs BIOS is usually loaded starting at address 0xffff0000, and it is exactly 64k long. The usage of external large BIOS images (up to 512k) at memory top is now supported, but we still recommend to use the BIOS distributed with Bochs.

`file`

Name of the BIOS image file. You can use the environment variable $BXSHARE to specify the location of the BIOS.

`address`

The start address is optional, since it can be calculated from image size.

`options`

The Bochs BIOS currently supports only the option "fastboot" to skip the boot menu delay.

`flash_dats`

This parameter defines the file name for the flash BIOS config space loaded startup if existing and saved on exit if modified. The Bochs BIOS doesn't this feature yet.

If you use the BIOS-bochs-legacy romimage BIOS option, you cannot use a PCI enabled VGA ROM BIOS.

#### vgaromimage

Examples:

      vgaromimage: file=bios/VGABIOS-elpin-2.40
      vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest
      vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest-cirrus

This tells Bochs what VGA ROM BIOS to load (at 0xC0000).

A VGA BIOS from Elpin Systems, Inc. as well as a free LGPL'd VGA BIOS are provided in the source and binary distributions.

Please check with the vga option to decide what VGA BIOS to use. If you use the BIOS-bochs-legacy romimage BIOS option, you cannot use a PCI enabled VGA ROM BIOS.

#### optromimage1, optromimage2, optromimage3 or optromimage4

Example:

       optromimage1: file=optionalrom.bin, address=0xd0000

This enables Bochs to load up to 4 optional ROM images.

Be sure to use a read-only area, typically between C8000 and EFFFF. These optional ROM images should not overwrite the rombios (located at F0000-FFFFF) and the videobios (located at C0000-C7FFF).

Those ROM images will be initialized by the BIOS if they contain the right signature (0x55AA).

It can also be a convenient way to upload some arbitrary code/data in the simulation, that can be retrieved by the boot loader

#### vga

Examples:

      vga: extension=cirrus, update_freq=10, realtime=1, ddc=file:monitor.bin
      vga: extension=vbe

This defines parameters related to the VGA display

The 'extension' option can be used to specify the VGA display extension. With the value 'none' you can use standard VGA with no extension. Other supported values are 'vbe' for Bochs VBE (needs `VGABIOS-lgpl-latest` as VGA BIOS, see vgaromimage option), 'cirrus' for Cirrus SVGA support (needs `VGABIOS-lgpl-latest-cirrus` as VGA BIOS) and 'voodoo' for Voodoo Graphics support (needs `VGABIOS-lgpl-latest-banshee` as VGA BIOS / see voodoo-notes for more information).

The VGA update frequency specifies the number of display updates per second. The VGA update timer by default uses the realtime engine with a value of 10 (valid: 1 to 75). This parameter can be changed at runtime. The special value 0 enables support for using the frame rate of the emulated graphics device.

The 'realtime' option specifies the operation mode of the VGA update timer. If set to 1, the VGA timer is based on realtime, otherwise it is based on the ips setting. If the host is slow (low ips, update_freq) and the guest uses HLT appropriately, setting this to 0 and "clock: sync=none" may improve the responsiveness of the guest GUI when the guest is otherwise idle. The default value is 1.

The parameter 'ddc' defines the behaviour of the DDC emulation that returns the monitor EDID data. By default, the 'builtin' values for 'Bochs Screen' are used. Other choices are 'disabled' (no DDC emulation) and 'file' (read monitor EDID from file / path name separated with a colon).

#### voodoo

Example:

      voodoo: enabled=1, model=voodoo1

This defines the Voodoo Graphics emulation (experimental). Currently supported models are 'voodoo1', 'voodoo2', 'banshee' and 'voodoo3'. The Voodoo2 support is not yet complete, but almost usable. The Banshee / Voodoo3 support is under construction, but basically usable. The 2D/3D cards require the vga extension option to be set to 'voodoo'. If the i440BX PCI chipset is selected, they can be assigned to AGP (slot #5). The GUI screen update timing for all models is controlled by the related 'vga' options. See voodoo-notes for more information.

#### keyboard

Examples:

      keyboard: type=mf, serial_delay=150, paste_delay=100000
      keyboard: keymap=gui/keymaps/x11-pc-de.map
      keyboard: user_shortcut=ctrl-alt-del

This defines parameters related to the emulated keyboard.

`type`

Type of keyboard return by a "identify keyboard" command to the keyboard controller. It must be one of "xt", "at" or "mf". Defaults to "mf". It should be ok for almost everybody. A known exception is French macs, that do have a "at"-like keyboard.

`serial_delay`

Approximate time in microseconds that it takes one character to be transferred from the keyboard to controller over the serial path.

`paste_delay`

Approximate time in microseconds between attempts to paste characters to the keyboard controller. This leaves time for the guest os to deal with the flow of characters. The ideal setting depends on how your operating system processes characters. The default of 100000 usec (.1 seconds) was chosen because it works consistently in Windows.

If your OS is losing characters during a paste, increase the paste delay until it stops losing characters.

`keymap`

This enables a remap of a physical localized keyboard to a virtualized us keyboard, as the PC architecture expects.

Keyboard mapping is available for the display libraries x, sdl (Linux port) and wx (GTK port). For SDL you have to use keymaps designed for SDL, the wxWidgets GUI uses the keymaps for X11.

`user_shortcut`

This defines the keyboard shortcut to be sent when you press the "user" button in the headerbar. The shortcut string is a combination of maximum 3 key names (listed below) separated with a '-' character.

Valid key names:

"alt", "bksl", "bksp", "ctrl", "del", "down", "end", "enter", "esc", "f1", ... "f12", "home", "ins", "left", "menu", "minus", "pgdwn", "pgup", "plus", "power", "print", "right", "scrlck", "shift", "space", "tab", "up" and "win".

#### mouse

Examples:

      mouse: enabled=1
      mouse: type=imps2, enabled=1
      mouse: type=serial, enabled=1
      mouse: enabled=0, toggle=ctrl+f10

This defines parameters for the emulated mouse type, the initial status of the mouse capture and the runtime method to toggle it.

`type`

With the mouse type option you can select the type of mouse to emulate. The default value is 'ps2'. The other choices are 'imps2' (wheel mouse on PS/2), 'serial', 'serial_wheel', 'serial_msys' (one com port requires setting 'mode=mouse', see com option) 'inport' and 'bus' (if present). To connect a mouse to a USB port, see the usb_uhci, 'usb_ohci', 'usb_ehci' or 'usb_xhci' options (requires PCI and USB support).

`enabled`

The Bochs GUI creates mouse "events" unless the 'enabled' option is set to 0. The hardware emulation itself is not disabled by this. Unless you have a particular reason for enabling the mouse by default, it is recommended that you leave it off. You can also toggle the mouse usage at runtime (see headerbar and the 'toggle' option below).

`toggle`

The default method to toggle the mouse capture at runtime is to press the CTRL key and the middle mouse button ('ctrl+mbutton'). This option allows to change the method to 'ctrl+f10' (like DOSBox) or 'ctrl+alt' (like QEMU) or 'f12'.

#### pci

This defines the parameters to set up the Bochs PCI emulation:

Examples:

      pci: enabled=1, chipset=i440fx # default if compiled with PCI support
      pci: enabled=1, chipset=i440fx, slot1=pcivga, slot2=ne2k, advopts=noacpi
      pci: enabled=1, chipset=i440bx, slot5=voodoo, slot1=e1000

`enabled`

If Bochs is compiled with PCI support, it is enabled by default.

`chipset`

Currently the chipsets i430FX, i440FX and i440BX (limited) are supported and the default is i440FX.

`slot`X``

It is possible to specify the devices connected to PCI slots. Up to 5 slots are available. For combined PCI/ISA devices assigning to slot is mandatory if the PCI model should be emulated (cirrus, ne2k and pcivga). Setting up slot for PCI-only devices is also supported, but they are auto-assigned if not specified (e1000, es1370, pcidev, pcipnic, usb_ehci, usb_ohci, usb_xhci, voodoo). All device models except the network devices ne2k and e1000 can be used only once in the slot configuration. In case of the i440BX chipset, the slot #5 is the AGP slot. Currently only the 'voodoo' device can be assigned to AGP.

`advopts`

With the advanced PCI options, it is possible to control the behaviour of the PCI chipset. These options can be specified as comma-separated values. By default, the "Bochs i440FX" chipset enables the ACPI and HPET devices, but original i440FX doesn't support them. The options 'noacpi' and 'nohpet' make it possible to disable them. The option 'noagp' disables the incomplete AGP subsystem of the i440BX chipset.

#### clock

This defines the parameters of the clock inside Bochs:

`sync`

This defines the method how to synchronize the Bochs internal time with realtime. With the value 'none' the Bochs time relies on the IPS value and no host time synchronization is used. The 'slowdown' method sacrifices performance to preserve reproducibility while allowing host time correlation. The 'realtime' method sacrifices reproducibility to preserve performance and host-time correlation. It is possible to enable both synchronization methods.

`rtc_sync`

If this option is enabled together with the realtime synchronization, the RTC runs at realtime speed. This feature is disabled by default.

`time0`

Specifies the start (boot) time of the virtual machine. Use a time value as returned by the time(2) system call or a string as returned by the ctime(3) system call. If no time0 value is set or if time0 equal to 1 (special case) or if time0 equal 'local', the simulation will be started at the current local host time. If time0 equal to 2 (special case) or if time0 equal 'utc', the simulation will be started at the current utc time.

    Syntax:
      clock: sync=[none|slowdown|realtime|both], time0=[timeValue|local|utc]

    Examples:
      clock: sync=none,     time0=local       # Now (localtime)
      clock: sync=slowdown, time0=315529200   # Tue Jan  1 00:00:00 1980
      clock: sync=none,     time0="Mon Jan  1 00:00:00 1990" # 631148400
      clock: sync=realtime, time0=938581955   # Wed Sep 29 07:12:35 1999
      clock: sync=realtime, time0="Sat Jan  1 00:00:00 2000" # 946681200
      clock: sync=none,     time0=1           # Now (localtime)
      clock: sync=none,     time0=utc         # Now (utc/gmt)

    Default value are sync=none, rtc_sync=0, time0=local

#### cmosimage

Example:

      cmosimage: file=cmos.img, rtc_init=time0

This defines a binary image file with size 128 bytes that can be loaded into the CMOS RAM at startup. The rtc_init parameter controls whether initialize the RTC with values stored in the image. By default, the time0 argument given to the clock option is used. With 'rtc_init=image' the image is the source for the initial time.

#### private_colormap

Example:

      private_colormap: enabled=1

Requests that the GUI creates and uses its own non-shared colormap. This colormap will be used when in the Bochs window. If not enabled, a shared colormap scheme may be used. Once again, `enabled=1` turns on this feature and 0 turns it off.

#### floppya/floppyb

Examples:

    2.88M 3.5" media:
      floppya: 2_88=a:, status=inserted
    1.44M 3.5" media (write protected):
      floppya: 1_44=floppya.img, status=inserted, write_protected=1
    1.2M  5.25" media:
      floppyb: 1_2=/dev/fd0, status=inserted
    720K  3.5" media:
      floppya: 720k=/usr/local/bochs/images/win95.img, status=inserted
    auto-detect floppy media type:
      floppya: image=floppy.img, status=inserted
    use directory as VFAT media:
      floppya: 1_44=vvfat:path, status=inserted
    1.44M 3.5" floppy drive, no media:
      floppya: type=1_44

Floppya is the first drive, and floppyb is the second drive. If you're booting from a floppy, floppya should point to a bootable disk. To read from a disk image, write the name of the image file. In many operating systems Bochs can read directly from a raw floppy drive. For raw disk access, use the device name (Unix systems) or the drive letter and a colon (Windows systems).

Following floppy media types are supported: 2_88, 1_44, 1_2, 720k, 360k, 320k, 180k, 160k, as well as "image" to let Bochs auto-detect the type of floppy media (does only work with images, not with raw floppy drives). In that case the size must match one of the supported types.

You can set the initial status of the media to `ejected` or `inserted`. Usually, you will want to use `inserted`.

The parameter 'type' can be used to enable the floppy drive without media and status specified. Usually, the drive type is set up based on the media type.

The optional parameter 'write_protected' can be used to control the media write protect switch. By default, it is turned off.

#### ata0, ata1, ata2, ata3

Examples:

    ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
    ata1: enabled=1, ioaddr1=0x170, ioaddr2=0x370, irq=15
    ata2: enabled=1, ioaddr1=0x1e8, ioaddr2=0x3e0, irq=11
    ata3: enabled=1, ioaddr1=0x168, ioaddr2=0x360, irq=9

These options enable up to 4 ata channels. For each channel the two base io addresses and the irq must be specified. ata0 and ata1 are enabled by default, with the values shown above.

#### ata0-master, ata0-slave, ata1-*, ata2-*, ata3-*

Examples:

    ata0-master: type=disk, path=10M.img, mode=flat, cylinders=306, heads=4, spt=17, translation=none
    ata1-master: type=disk, path=2GB.cow, mode=vmware3, cylinders=5242, heads=16, spt=50, translation=echs
    ata1-slave:  type=disk, path=3GB.img, mode=sparse, cylinders=6541, heads=16, spt=63, translation=auto
    ata2-master: type=disk, path=7GB.img, mode=undoable, cylinders=14563, heads=16, spt=63, translation=lba
    ata2-slave:  type=cdrom, path=iso.sample, status=inserted

This defines the type and characteristics of all attached ata devices:

#### ata devices configuration options

Option | Comments | Possible values
type | type of attached device | [disk | cdrom]
path | path of the image
mode | image type, only valid for disks | [flat | concat | dll | sparse | vmware3 | vmware4 | undoable | growing | volatile | vpc | vbox | vvfat ]
cylinders | only valid for disks
heads | only valid for disks
spt | only valid for disks
status | only valid for CD-ROMs | [inserted | ejected]
biosdetect | type of biosdetection | [auto | cmos | none]
translation | type of translation done by the BIOS (legacy int13), only for disks | [none | lba | large | rechs | auto]
model | string returned by identify device ATA command
journal | optional filename of the redolog for undoable, volatile and vvfat disks

You have to tell the type of the attached device. For Bochs 2.0 or later, it can be `disk` or `cdrom`.

You have to point the "path" at a hard disk image file, CD-ROM iso file, or physical CD-ROM device. To create a hard disk image, try running `bximage` (see diskimagehowto). It will help you choose the size and then suggest a line that works with it.

In Unix it is possible to use a raw device as a Bochs hard disk, but we don't recommend it for safety reasons. In Windows, there is no easy way.

Disk geometry autodetection works with images created by bximage if CHS is set to 0/0/0 (cylinders are calculated using heads=16 and spt=63). For other hard disk images and modes the cylinders, heads, and spt are mandatory. In all cases the disk size reported from the image must be exactly C*H*S*512. Flat hard disk images from other projects might store additional information at the end of the file that makes this check fail. Only in this case it is safe to select "continue" when Bochs panics.

The disk translation scheme (implemented in legacy int13 BIOS functions, and used by older operating systems like MS-DOS), can be defined as:

- none : no translation, for disks up to 528MB (1032192 sectors)

- large : a standard bitshift algorithm, for disks up to 4.2GB (8257536 sectors)

- rechs : a revised bitshift algorithm, using a 15 heads fake physical geometry, for disks up to 7.9GB (15482880 sectors). (don't use this unless you understand what you're doing)

- lba : a standard lba-assisted algorithm, for disks up to 8.4GB (16450560 sectors)

- auto : autoselection of best translation scheme. (it should be changed if system does not boot)

Please see bios-disk-translation for a discussion on translation scheme.

The mode option defines how the disk image is handled. Disks can be defined as:

- flat : one file flat layout

- concat : multiple files layout

- dll : developer's specific, through a DLL

- sparse : stackable, commitable, rollbackable

- vmware3 : vmware version 3 disk support

- vmware4 : vmware version 4 disk support (aka VMDK)

- undoable : read-only base file with commitable redolog

- growing : growing file

- volatile : read-only base file with volatile redolog

- vpc: fixed / dynamic size VirtualPC image

- vbox: fixed / dynamic size Oracle(tm) VM VirtualBox image (VDI version 1.1)

- vvfat: local directory appears as VFAT disk (with volatile redolog / optional commit)

Please see harddisk-modes for a discussion on disk modes.

Default values are:

       mode=flat, biosdetect=auto, translation=auto, model="Generic 1234"

The `biosdetect` option has currently no effect on the BIOS.

Make sure the proper ata option is enabled when using a device on that ata channel.

#### boot

Examples:

      boot: floppy
      boot: cdrom, disk
      boot: network, disk
      boot: cdrom, floppy, disk

This defines the boot sequence. You can specify up to 3 boot drives, which can be 'floppy', 'disk', 'cdrom' or 'network' (boot ROM). Legacy 'a' and 'c' are also supported.

#### floppy_bootsig_check

Example:

      floppy_bootsig_check: disabled=1

This disables the 0xaa55 signature check on boot floppies The check is enabled by default.

#### log

Examples:

      log: bochsout.txt
      log: -
      log: /dev/tty               (Unix only)
      log: /dev/null              (Unix only)
      log: nul                    (win32 only)

Give the path of the log file you'd like Bochs debug and misc. verbiage to be to be written to. If you don't use this option or set the filename to '-' the output is written to the console. If you really don't want it, make it "/dev/null" (Unix) or "nul" (win32). :^(

#### logprefix

Examples:

       logprefix: %t-%e-@%i-%d
       logprefix: %i%e%d

This handles the format of the string prepended to each log line. You may use those special tokens:

      %t : 11 decimal digits timer tick
      %i : 8 hexadecimal digits of current cpu eip (ignored in SMP configuration)
      %e : 1 character event type ('i'nfo, 'd'ebug, 'p'anic, 'e'rror)
      %d : 5 characters string of the device, between brackets

Default is %t%e%d

#### debug/info/error/panic

Examples:

      debug: action=ignore, pci=report
      info: action=report
      error: action=report
      panic: action=ask

During simulation, Bochs encounters certain events that the user might want to know about. These events are divided into four levels of importance: debug, info, error, and panic. Debug messages are usually only useful when writing Bochs code or when trying to locate a problem. There may be thousands of debug messages per second, so be careful before turning them on. Info messages tell about interesting events that don't happen that frequently. Bochs produces an "error" message when it finds a condition that really shouldn't happen, but doesn't endanger the simulation. An example of an error might be if the emulated software produces an illegal disk command. Panic messages mean that Bochs cannot simulate correctly and should probably shut down. A panic can be a configuration problem (like a misspelled bochsrc line) or an emulation problem (like an unsupported video mode).

The debug, info, error, and panic lines in the bochsrc control what Bochs will do when it encounters each type of event. The allowed actions are: fatal (terminate Bochs), ask (ask the user what to do), warn (show dialog with message and continue), report (print information to the console or log file), or ignore (do nothing). The recommended settings are listed in the sample above.

It is also possible to specify the 'action' to do for each Bochs facility separately (e.g. crash on panics from everything except the CD-ROM, and only report those). See the log function module table for valid module names.

The safest action for panics is "fatal" or "ask". If you are getting lots of panics and get tired of telling it to continue each time, you can try action=report instead. If you allow Bochs to continue after a panic, don't be surprised if you get strange behavior or crashes after a panic occurs. Please report panic messages to the &devlist; unless it is just a configuration problem like "could not find hard drive image."

#### debugger_log

Examples:

      debugger_log: debugger.out
      debugger_log: /dev/null              (Unix only)
      debugger_log: -

Give the path of the log file you'd like Bochs to log debugger output. If you really don't want it, make it '/dev/null', or '-'.

#### com[1-4]

Examples:

      com1: enabled=1, mode=null
      com1: enabled=1, mode=mouse
      com1: enabled=1, mode=term, dev=/dev/ttyp9
      com2: enabled=1, mode=file, dev=serial.out
      com3: enabled=1, mode=raw, dev=com1
      com3: enabled=1, mode=socket-client, dev=localhost:8888
      com3: enabled=1, mode=socket-server, dev=localhost:8888
      com4: enabled=1, mode=pipe-client, dev=\\.\pipe\mypipe
      com4: enabled=1, mode=pipe-server, dev=\\.\pipe\mypipe

This defines a serial port (UART type 16550A).

When using the mode 'term', you can specify a device to use as com1. This can be a real serial line, or a pty. To use a pty (under X/Unix), create two windows (xterms, usually). One of them will run Bochs, and the other will act as com1. Find out the tty of the com1 window using the `tty' command, and use that as the `dev' parameter. Then do `sleep 1000000' in the com1 window to keep the shell from messing with things, and run Bochs in the other window. Serial I/O to com1 (port 0x3f8) will all go to the other window.

When using socket* and pipe* (win32 only) modes Bochs becomes either socket/named pipe client or server. In client mode it connects to an already running server (if connection fails Bochs treats com port as not connected). In server mode it opens socket/named pipe and waits until a client application connects to it before starting simulation. This mode is useful for remote debugging (e.g. with gdb's "target remote host:port" command or windbg's command line option -k com:pipe,port=\\.\pipe\pipename). Socket modes use simple TCP communication, pipe modes use duplex byte mode pipes.

Other serial modes are 'null' (no input/output), 'file' (output to a file specified as the 'dev' parameter and changeable at runtime), 'raw' (use the real serial port - partly implemented on win32), 'mouse' (standard serial mouse - requires mouse option setting 'type=serial', 'type=serial_wheel' or 'type=serial_msys').

#### parport[1-2]

Examples:

      parport1: enabled=1, file="parport.out"
      parport2: enabled=1, file="/dev/lp0"
      parport1: enabled=0

This defines a parallel (printer) port. When turned on and an output file is defined, the emulated printer port sends characters printed by the guest OS into the output file. On some platforms, a device filename can be used to send the data to the real parallel port (e.g. "/dev/lp0" on Linux, "lpt1" on win32 platforms). The output file can be changed at runtime.

#### sound

Example for one driver (uses platform-default):

      sound: driver=default, waveout=/dev/dsp

Example for different drivers:

      sound: waveoutdrv=sdl, waveindrv=alsa, midioutdrv=dummy

This defines the lowlevel sound driver(s) for the wave (PCM) input / output and the MIDI output feature and (if necessary) the devices to be used. It can have several of the following properties. All properties are in the format sound: property=value.

- `waveoutdrv`: This defines the driver to be used for the waveout feature. Possible values are 'file' (all wave data sent to file), 'dummy' (no output) and the platform-dependant drivers 'alsa', 'oss', 'osx', 'sdl' and 'win'.

- `waveout`: This defines the device to be used for wave output (if necessary) or the output file for the 'file' driver.

- `waveindrv`: This defines the driver to be used for the wavein feature. Possible values are 'dummy' (recording silence) and platform-dependent drivers 'alsa', 'oss', 'sdl' and 'win'.

- `wavein`: This defines the device to be used for wave input (if necessary).

- `midioutdrv`: This defines the driver to be used for the MIDI output feature. Possible values are 'file' (all MIDI data sent to file), 'dummy' (no output) and platform-dependent drivers 'alsa', 'oss', 'osx' and 'win'.

- `midiout`: This defines the device to be used for MIDI output (if necessary).

- `driver`: This defines the driver to be used for all sound features with one property. Possible values are 'default' (platform default) and all other choices described above. Overriding one or more settings with the specific driver parameter is possible.

See using-sound for more information.

#### speaker

Example:

      speaker: enabled=1, mode=sound

This defines the PC speaker output mode. In the 'sound' mode the beep is generated by the square wave generator which is a part of the lowlevel sound support. In this mode the 'volume' parameter can be used to set the output volume (0 - 15). The 'system' mode is only available on Linux and Windows. On Linux /dev/console is used for output and on Windows the Beep() function. The 'gui' mode forwards the beep to the related GUI methods (currently only used by the Carbon GUI).

#### sb16

Example:

      sb16: midimode=2, midifile=output.mid, wavemode=3, wavefile=output.wav
            loglevel=2, log=sb16.log, dmatimer=900000

The example is wrapped onto several lines for formatting reasons, but it should all be on one line in the actual `bochsrc` file.

This defines the Sound Blaster 16 emulation, see the developer documentation for more information. It can have several of the following properties. All properties are in the usual "property=value" format.

- `enabled`: This optional property controls the presence of the SB16 emulation. The emulation is turned on unless this property is used and set to 0.

- `midimode`: This parameter specifies what to do with the MIDI output.

          0 = no output
          1 = output to device specified with the sound option (system dependent)
          2 = MIDI or raw data output to file (depends on file name extension)
          3 = dual output (mode 1 and 2 at the same time)

- `midifile`: This is the file where the midi output is stored (midimode 2 or 3).

- `wavemode`: This parameter specifies what to do with the PCM output.

          0 = no output
          1 = output to device specified with the sound option (system dependent)
          2 = VOC, WAV or raw data output to file (depends on file name extension)
          3 = dual output (mode 1 and 2 at the same time)

- `wavefile`: This is the file where the wave output is stored (wavemode 2 or 3).

- `log`: The file to write the sb16 emulator messages to.

- `loglevel`:

         0 = No log.
         1 = Resource changes, midi program and bank changes.
         2 = Severe errors.
         3 = All errors.
         4 = All errors plus all port accesses.
         5 = All errors and port accesses plus a lot of extra information.

  It is possible to change the loglevel at runtime.

- `dmatimer`: Microseconds per second for a DMA cycle. Make it smaller to fix non-continuous sound. 1000000 is usually a good value. This needs a reasonably correct setting for the `ips` parameter of the cpu option und also denpends on the clock sync setting. It is possible to adjust the dmatimer value at runtime.

#### es1370

Examples:

      es1370: enabled=1, wavemode=1                       # use 'sound' parameters
      es1370: enabled=1, wavemode=2, wavefile=output.voc  # send output to file

This defines the ES1370 sound emulation (recording and playback - except DAC1+DAC2 output at the same time). The parameter 'enabled' controls the presence of the device. The wave and MIDI output can be sent to device, file or both using the parameters 'wavemode', 'wavefile', 'midimode' and 'midifile'. See the description of these parameters at the SB16 directive.

#### ne2k

The ne2k line configures an emulated NE2000-compatible Ethernet adapter, which allows the guest machine to communicate on the network. To disable the NE2000 just comment out the ne2k line.

Examples:

    ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=xl0
    ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=en0 #macosx
    ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=linux, ethdev=eth0
    ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=win32, ethdev=MYCARD
    ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=vde, ethdev="/tmp/vde.ctl"
    ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=vnet, ethdev="c:/temp"
    ne2k: ioaddr=0x300, irq=9, mac=fe:fd:00:00:00:01, ethmod=tap, ethdev=tap0
    ne2k: ioaddr=0x300, irq=9, mac=fe:fd:00:00:00:01, ethmod=tuntap, ethdev=/dev/net/tun0, script=./tunconfig
    ne2k: mac=b0:c4:20:00:00:01, ethmod=socket, ethdev=40000 # use localhost
    ne2k: card=0, mac=b0:c4:20:00:00:01, ethmod=socket, ethdev=mymachine:40000
    ne2k: mac=b0:c4:20:00:00:01, ethmod=slirp, script=slirp.conf, bootrom=ne2k_pci.rom

    CARD: This is the zero-based card number to configure with this ne2k config
    line. Up to 4 devices are supported now (0...3). If not specified, the
    following parameters apply to card #0.

    TYPE: This is the card type to emulate ("isa" or "pci"). If not specified,
    card #0 defaults to "pci" if assigned to a pci slot. For the additional cards
    the type parameter should be set up.

    IOADDR, IRQ: You probably won't need to change ioaddr and irq, unless there
    are IRQ conflicts. These parameters are ignored if the NE2000 is assigned to
    a PCI slot.

    MAC: The MAC address MUST NOT match the address of any machine on the net.
    Also, the first byte must be an even number (bit 0 set means a multicast
    address), and you cannot use ff:ff:ff:ff:ff:ff because that's the broadcast
    address.  For the ethertap module, you must use fe:fd:00:00:00:01.  There may
    be other restrictions too.  To be safe, just use the b0:c4... address.

    ETHMOD: The ethmod value defines which low level OS specific module to be
    used to access physical ethernet interface. You can also specify a network
    simulator or a module with no input/output ("null"). See the table below for
    currently supported values.

    ETHDEV: The ethdev value is the name of the network interface on your host
    platform.  On UNIX machines, you can get the name by running ifconfig.  On
    Windows machines, you must run niclist to get the name of the ethdev.
    Niclist source code is in misc/niclist.c and it is included in Windows
    binary releases.

    SCRIPT: The script value is optional, and is the name of a script that
    is executed after Bochs initialize the network interface. You can use
    this script to configure this network interface, or enable masquerading.
    This is mainly useful for the tun/tap devices that only exist during
    Bochs execution. The network interface name is supplied to the script
    as first parameter. The 'slirp' module uses this parameter to specify a config
    file for setting up an alternative IP configuration or additional features.
    The 'vnet' module also uses this parameter to specify a config file similar
    to slirp, but with only a few settings.

    BOOTROM: The bootrom value is optional, and is the name of the ROM image
    to load. Note that this feature is only implemented for the PCI version of
    the NE2000. For the ISA version using one of the optromimage options
    (see bochsopt-optrom) must be used instead of this one.

The following table shows the available ethernet modules with description, whether the "ethdev" and "script" parameters are used or not and the Bochs version where this module was added.

#### Ethernet modules

Module | Description | ethdev | script | Bochs version
fbsd | FreeBSD / OpenBSD packetmover. | Yes | No | 1.0
linux | Linux packetmover - 'root' privileges required, no connection to the host machine. | Yes | No | 1.3
null | Null packetmover. All packets are discarded, but logged to a few files. | No | No | 1.0
tap | TAP packetmover. | Yes | Yes | 1.4
tuntap | TUN/TAP packetmover - see Configuring and using a tuntap network interface. | Yes | Yes | 2.0
vde | Virtual Distributed Ethernet packetmover. | Yes | Yes | 2.2
vnet | ARP, ping (ICMP-echo), DHCP, DNS , FTP and TFTP simulation. The virtual host uses 192.168.10.1. DHCP assigns 192.168.10.15 to the guest. The FTP and TFTP servers use the 'ethdev' value for the root directory. TFTP doesn't overwrite files, DNS for server and client only. | Yes, for FTP and TFTP root | Yes, for log file name | 2.2
slirp | Built-in Slirp support with DHCP / TFTP servers. Adds user mode networking to Bochs - see Using the 'slirp' networking module. The 'script' parameter can be used to set up an alternative IP configuration or additional features. The TFTP server uses the 'ethdev' value for the root directory and doesn't overwrite files. | Yes, for TFTP root | Yes, for Slirp config | 2.6.5
socket | Connect up to 6 Bochs instances on the same or other machine with external program 'bxhub' (simulating an ethernet hub). It provides the same services as the 'vnet' module and assigns IP addresses like 'slirp' (10.0.2.x) (see Using the 'socket' networking module). | Yes, for base UDP port and (optional) the host to connect | No | 2.6.9
win32 | Win32 packetmover - WinPCap driver required. | Yes | No | 1.3

#### pcipnic

Example:

      pcipnic: enabled=1, mac=b0:c4:20:00:00:00, ethmod=vnet

To support the Bochs/Etherboot pseudo-NIC, Bochs must be compiled with the `--enable-pnic` configure option. It accepts the same syntax (for mac, ethmod, ethdev, script, bootrom) and supports the same networking modules as the NE2000 adapter.

#### e1000

Example:

      e1000: enabled=1, mac=52:54:00:12:34:56, ethmod=slirp, script=slirp.conf

To support the Intel(R) 82540EM Gigabit Ethernet adapter, Bochs must be compiled with the `--enable-e1000` configure option. It accepts the same syntax (for mac, ethmod, ethdev, script, bootrom) and supports the same networking modules as the NE2000 adapter.

#### usb_uhci

Examples:

      usb_uhci: port1=mouse, port2=disk, options2="path:usbstick.img"
      usb_uhci: port1=hub, options1="ports:6, pcap:outfile.pcap"
      usb_uhci: port2=disk, options2="path:undoable:usbdisk.img, journal:u.redolog"
      usb_uhci: port2=disk, options2=""path:usbdisk2.img, sect_size:1024"
      usb_uhci: port2=disk, options2="path:vvfat:vvfat, debug, speed:full"
      usb_uhci: port2=cdrom, options2="path:image.iso"
      usb_uhci: port1=printer, options1="file:printdata.bin"
      usb_uhci: port2=floppy, options2="path:vvfat:diskette, model:teac"

This option controls the presence of the USB root hub which is a part of the i440FX PCI chipset.

With the port`X` option you can connect devices to the hub (currently supported: 'mouse', 'tablet', 'keypad', 'keyboard', 'disk', 'cdrom', 'floppy, ''hub' and 'printer'). See bochsopt-usb-config for more information on each device setting.

If you connect the mouse or tablet to one of the ports, Bochs forwards the mouse movement data to the USB device instead of the selected mouse type. When connecting the keypad to one of the ports, Bochs forwards the input of the numeric keypad to the USB device instead of the PS/2 keyboard. If the keyboard is selected, all key events are sent to the USB device.

To connect a disk image as a USB hardisk you can use the 'disk' device. Use the 'path' option in the options`X` parameter to specify the path to the image separated with a colon. To use other disk image modes similar to ATA disks the syntax 'path:mode:filename' must be used (see below).

To emulate a USB CD-ROM you can use the 'cdrom' device and the path to an ISO image or raw device name can be set with the 'path' option in the options`X` parameter also separated with a colon. An option to insert/eject media is available in the runtime configuration.

To emulate a USB floppy, you can use the 'floppy' device and the path to a floppy image can be set with the 'path' option in the options`X` parameter separated with a colon. To use the VVFAT image mode similar to the legacy floppy the syntax 'path:vvfat:directory' must be used (see below). An option to insert/eject media is available in the runtime configuration. A well-known, somewhat older, but still widely used Operating System must have the Vendor ID as an TEAC external drive. If the VendorID is not the TEAC id, this operating system doesn't know what to do with the drive. Therefore, use the options`X`="model:teac" option in the bochsrc.txt file to set this model. If you do not, a default model will be used.

The device name 'hub' connects an external hub with a maximum of 8 ports (default: 4) to the root hub. To specify the number of ports you have to use the 'ports' option in the options`X` parameter with the value separated with a colon. Connecting devices to the external hub ports is only available in the runtime configuration.

The device 'printer' emulates the HP Deskjet 920C printer. The PCL data is sent to a file specified in the 'file' option with the options`X` parameter. The current code appends the PCL code to the file if the file already existed. The output file can be changed at runtime.

The options`X` parameter can also be used to assign specific options to the device connected to the corresponding USB port. The option 'speed' can be used to set the speed reported by device ('low', 'full', 'high' or 'super'). The available speed choices depend on both HC and device. The option 'debug' turns on debug output for the device at connection time. The option 'pcap' turns on packet logging in PCAP format. For the USB 'disk' device the options`X` parameter can be used to specify an alternative redolog file (journal) of some image modes. For 'vvfat' mode USB disks the options`X` parameter can be used to specify the disk size (range 128M ... 128G). If the size is not specified, it defaults to 504M. For the USB 'floppy' device the options`X` parameter can be used to specify an alternative device ID to be reported. Currently only the model "teac" is supported (can fix hw detection in some guest OS). The USB floppy also accepts the parameter "write_protected" with valid values 0 and 1 to select the access mode (default is 0).

For USB disk image emulation using the 'disk' or 'cdrom' type, an options`X` parameter of 'proto:bbb' or 'proto:uasp' may be used. The former tells Bochs to use the 'Bulk/Bulk/Bulk' protocol, aka the 'Bulk only' protocol. This is the standard protocol that most USB disks will use, and is used by default. The latter option tells Bochs to use the newer 'USB Attached SCSI' protocol, used on newer, more modern USB disks. If the 'proto:' parameter is not given, Bochs will default to the 'bbb' protocol. See the 'ehci' and 'xhci' examples below.

PCI support must be enabled to use USB UHCI.

The BBB protocol must have a speed option of 'full', 'high', or 'super'. The UASP protocol can only be used on high- and super-speed devices, therefore must only be used with the 'usb_ehci' and 'usb_xhci' configuration options. Full-speed devices will default to the BBB protocol.

Specifying the UASP option does not guarantee the Guest will use this interface. The Bochs emulation still gives both options. It is up to the Guest to choose which protocol to use. A modern, widely used OS will default to BBB for various EHCI controllers, and controllers that are known to have issues with this type of protocol.

The USB emulation now checks many items for accuracy. For example, it will monitor the toggle bit in a Transfer Descriptor. If it is not correct, the TD will not be executed. If your code use to work in a Bochs emulation, but now it does not, check your toggle bit implementation. (This particular check can be disabled using the HANDLE_TOGGLE_CONTROL define in 'usb_common.h') Other checks for accuracy are checks for the 'value' and 'index' fields of a SETUP packet. For example, a particular request may specify that the 'value' field must be zero. Bochs now checks for this. Other checks include the Command Length field in a SCSI command request, valid values in an xHCI 'slot' and 'endpoint' context, as well as other checks.

#### usb_ohci

Example:

      usb_ohci: enabled=1, port1=printer:printdata.bin

This option controls the presence of the USB OHCI host controller with a 2-port hub. The port`X` parameter accepts the same device types with the same syntax as the UHCI controller (see the usb_uhci option). The options`X` parameter is also available on OHCI.

#### usb_ehci

Example:

      usb_ehci: enabled=1, port1=tablet, options1="speed:high"
      usb_ehci: enabled=1, port1=disk, options1="speed:high, path:hdd.img, proto:bbb"
      usb_ehci: enabled=1, port1=disk, options1="speed:high, path:hdd.img, proto:uasp"
      usb_ehci: enabled=1, port1=cdrom, options1="speed:high, path:bootcd.iso, proto:bbb"
      usb_ehci: enabled=1, port1=cdrom, options1="speed:high, path:bootcd.iso, proto:uasp"

This option controls the presence of the USB EHCI host controller with a 6-port hub. The port`X` parameter accepts the same device types with the same syntax as the UHCI controller (see the usb_uhci option). The options`X` parameter is also available on EHCI.

#### usb_xhci

Example:

      usb_xhci: enabled=1, model="uPD720202", n_ports=4
      usb_xhci: enabled=1, port1="disk:usbdisk.img"      # defaults to the BBB protocol
      usb_xhci: port1=disk, options1="speed:super, path:usbdisk.img, proto:uasp"
      usb_xhci: port1=disk, options1="speed:super, path:usbdisk.img, proto:bbb"
      usb_xhci: port1=cdrom, options1="speed:super, path:bootcd.iso, proto:uasp"
      usb_xhci: port3=disk, options3="speed:high, path:usbdisk.img, proto:uasp"
      usb_xhci: port3=disk, options3="speed:high, path:usbdisk.img, proto:bbb"
      usb_xhci: port3=floppy, options3="speed:full, path:floppy.img, model:teac"
      usb_xhci: port3=tablet, options3="speed:low"

This option controls the presence of the USB xHCI host controller with a default 4-port hub. The port`X` parameter accepts similar device types with a similar syntax as the UHCI controller (see the usb_uhci option). The options`X` parameter is also available on xHCI.

The xHCI supports up to two models, the NEC uPD720202 and the NEC uPD720201. The former defaults to a 4-port hub (two physical sockets), while the latter defaults to an 8-port hub (four physical sockets). This was added for future expansion. The 'n_ports=`n`' parameter can be given to override the count of ports used. This count must be at least two and not more than USB_XHCI_PORTS_MAX (currently 10), and must be an even numbered count.

No matter the count of ports, the first half (ports 1, 2, 3, and 4 on an 8-port hub) will be the USB3 ports (register sets), while the second half (ports 5, 6, 7, and 8) will be the USB2 ports (register sets). When the 'options`X`="speed:" option is used, it must contain 'super' for the first half ports (1, 2, 3, and 4) and the second half (5, 6, 7, and 8) must use a speed of 'low', 'full', or 'high'.

On an xHCI, the number of ports used is the number of port register sets, one set for the USB3 protocol and a paired set for the USB2 protocol. An 'n_ports=' specification of 4 defines two physical sockets.

#### pcidev

Example:

      pcidev: vendor=0xbabe, device=0x2bad

Enables the mapping of a host PCI hardware device within the virtual PCI subsystem of the Bochs x86 emulator. The arguments `vendor` and `device` should contain the PCI vendor ID respectively the PCI device ID of the host PCI device you want to map within Bochs.

The PCI device mapping is still in a very early stage of development and thus it is very experimental. This feature requires Linux as a host operating system.

Besides the `pcidev` config line you will need to load a pcidev kernel module within your Linux host OS. This kernel module is located in the `bochs/host/linux/pcidev/` directory.

#### gdbstub

Example:

      gdbstub: enabled=1, port=1234, text_base=0, data_base=0, bss_base=0

Default:

      gdbstub: enabled=0

This enables the GDB stub. See debugging-with-gdb.

#### magic_break

Example for breaking on "XCHGW %DI, %DI" or "XCHGW %SP, %SP" execution

      magic_break: enabled=1 di sp

If nothing is specified, the default will be used: XCHGW %BX, %BX Note: Windows XP ntldr can cause problems with XCHGW %BX, %BX

      magic_break: enabled=1

This enables the "magic breakpoint" feature when using the debugger. The useless cpu instruction XCHGW REGW, REGW causes Bochs to enter the debugger mode. This might be useful for software development.

      cx dx bx sp bp si di

#### debug_symbols

Example:

      debug_symbols: file=mysymbols.sym
      debug_symbols: file=mysymbols.sym, offset=0x1000

This loads symbols from the specified file for use in Bochs' internal debugger. Symbols are loaded into global context. This is equivalent to issuing ldsym debugger command at start up.

#### port_e9_hack

Example:

      port_e9_hack: enabled=1

      port_e9_hack: enabled=1, all_rings=1

The 0xE9 port doesn't exists in normal ISA architecture. However, we define a convention here, to display on the console of the system running Bochs anything that is written to it. The idea is to provide debug output very early when writing BIOS or OS code for example, without having to bother with setting up a serial port or etc. Reading from port 0xE9 will will return 0xe9 to let you know if the feature is available. Leave this 0 unless you have a reason to use it. By enabling the 'all_rings' option, you can utilize the port e9 hack from ring3.

#### IODEBUG

Example:

      iodebug: all_rings=1

I/O Interface to Bochs Debugger plugin allows the code running inside Bochs to monitor memory ranges, trace individual instructions, and observe register values during execution. By enabling the 'all_rings' option, you can utilize the iodebug ports from ring3. For more information, refer to "Advanced debugger usage" documentation.

### How to write your own keymap table

Christophe Bothamy wrote the keymapping code for Bochs, and provided this documentation for how to create new keymaps. Keymapping was first implemented for X windows only, so there are many references to X-specific values in this section. In Bochs 2.0 keymapping is also available for SDL (Linux port) and wxWidgets (wxGTK port).

      The standard US Keyboard looks like this:

              -------------------------------------------
      Top row Esc F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12
              -------------------------------------------
      2nd row ` 1 2 3 4 5 6 7 8 9 0 - = \ Back
              -------------------------------------------
      3rd row Tab Q W E R T Y U I O P [ ] Enter
              -------------------------------------------
      4rd row Caps A S D F G H J K L ; '
              -------------------------------------------
      5rd row lShift l\ Z X C V B N M , . / rShift
              -------------------------------------------
      6rd row lCtrl lAlt Space rAlt rCtrl
              -------------------------------------------

Each key of the US keyboard maps to a Bochs constant named BX_KEY_`symbol`. You can find the current list of BX_KEY_`symbol` in the BX_KEY table, below. Please note that there is only one BX_KEY_`symbol` for each physical key.

Now, for each key of the US keyboard, look at which symbols you can type on your real keyboard. Each symbol maps to a X-windows XK_`symbol` constant. In `X11/keysymdef.h`, you will find the list of all possible XK_`symbol` on your system. Alternatively, you can use a small utility called "xev" that prints out the symbol names of a pressed key. Note that the symbol name given by xev does not contain the XK_ prefix. Don't forget to add a line for every symbol you can type on each key. For the key BX_KEY_A, you can type both lowercase 'a' and uppercase 'A', so you would need two different entries.

You can then create your own map file. Keymap files are found in the "gui/keymaps" directory in the source code, or in the "keymaps" directory in binary releases. Look at the existing keymap file as an example, and create a file containing one line for each symbol. The first column tells what key or combination of keys can be used to produce a given symbol. The second column is the ASCII equivalent for that symbol, or a special keyword (none, space, return, tab, backslash, or apostrophe). The third column is the X windows keysym for that symbol.

For example :

    BX_KEY_0                                      '0'        XK_0
    BX_KEY_1                                      '1'        XK_1
    BX_KEY_2                                      '2'        XK_2
    BX_KEY_0+BX_KEY_SHIFT_L                       ')'        XK_parenright
    BX_KEY_1+BX_KEY_SHIFT_L                       '!'        XK_exclam
    BX_KEY_2+BX_KEY_SHIFT_L                       '@'        XK_at
    BX_KEY_A                                      'a'        XK_a
    BX_KEY_B                                      'b'        XK_b
    BX_KEY_A+BX_KEY_SHIFT_L                       'A'        XK_A
    BX_KEY_B+BX_KEY_SHIFT_L                       'B'        XK_B
    BX_KEY_TAB                                    tab        XK_Tab
    BX_KEY_ENTER                                  return     XK_Return
    BX_KEY_F1                                     none       XK_F1
    BX_KEY_F2                                     none       XK_F2
    BX_KEY_F3                                     none       XK_F3

Now that there are several keymap files in the Bochs distribution, it is easiest to copy an existing keymap and follow the examples you see. When it works, be sure to send it to the mailing list or post it on Source Forge so that we can include it in the next release. You may need to look up some of your country specific X11 symbols in `X11/keysymdef.h`.

### BX_KEY constants

BX_KEY constant | Keyboard Symbol
BX_KEY_CTRL_L | left Ctrl
BX_KEY_SHIFT_L | left Shift
BX_KEY_F1 | F1
BX_KEY_F2 | F2
BX_KEY_F3 | F3
BX_KEY_F4 | F4
BX_KEY_F5 | F5
BX_KEY_F6 | F6
BX_KEY_F7 | F7
BX_KEY_F8 | F8
BX_KEY_F9 | F9
BX_KEY_F10 | F10
BX_KEY_F11 | F11
BX_KEY_F12 | F12
BX_KEY_CTRL_R | right Ctrl
BX_KEY_SHIFT_R | right Shift
BX_KEY_CAPS_LOCK | CapsLock
BX_KEY_NUM_LOCK | NumLock
BX_KEY_ALT_L | left Alt
BX_KEY_ALT_R | right Alt
BX_KEY_A | A
BX_KEY_B | B
BX_KEY_C | C
BX_KEY_D | D
BX_KEY_E | E
BX_KEY_F | F
BX_KEY_G | G
BX_KEY_H | H
BX_KEY_I | I
BX_KEY_J | J
BX_KEY_K | K
BX_KEY_L | L
BX_KEY_M | M
BX_KEY_N | N
BX_KEY_O | O
BX_KEY_P | P
BX_KEY_Q | Q
BX_KEY_R | R
BX_KEY_S | S
BX_KEY_T | T
BX_KEY_U | U
BX_KEY_V | V
BX_KEY_W | W
BX_KEY_X | X
BX_KEY_Y | Y
BX_KEY_Z | Z
BX_KEY_0 | 0
BX_KEY_1 | 1
BX_KEY_2 | 2
BX_KEY_3 | 3
BX_KEY_4 | 4
BX_KEY_5 | 5
BX_KEY_6 | 6
BX_KEY_7 | 7
BX_KEY_8 | 8
BX_KEY_9 | 9
BX_KEY_ESC | Esc
BX_KEY_SPACE | SpaceBar
BX_KEY_SINGLE_QUOTE | '
BX_KEY_COMMA | ,
BX_KEY_PERIOD | .
BX_KEY_SLASH | /
BX_KEY_SEMICOLON | ;
BX_KEY_EQUALS | =
BX_KEY_LEFT_BRACKET | [
BX_KEY_BACKSLASH | \
BX_KEY_RIGHT_BRACKET | ]
BX_KEY_MINUS | -
BX_KEY_GRAVE | `
BX_KEY_BACKSPACE | BackSpace
BX_KEY_ENTER | Enter
BX_KEY_TAB | Tab
BX_KEY_LEFT_BACKSLASH | left \
BX_KEY_PRINT | PrintScreen
BX_KEY_SCRL_LOCK | ScrollLock
BX_KEY_PAUSE | Pause
BX_KEY_INSERT | Ins
BX_KEY_DELETE | Del
BX_KEY_HOME | Home
BX_KEY_END | End
BX_KEY_PAGE_UP | PageUo
BX_KEY_PAGE_DOWN | PageDown
BX_KEY_KP_ADD | Numeric Keypad +
BX_KEY_KP_SUBTRACT | Numeric Keypad -
BX_KEY_KP_END | Numeric Keypad 1
BX_KEY_KP_DOWN | Numeric Keypad 2
BX_KEY_KP_PAGE_DOWN | Numeric Keypad 3
BX_KEY_KP_LEFT | Numeric Keypad 4
BX_KEY_KP_5 | Numeric Keypad 5
BX_KEY_KP_RIGHT | Numeric Keypad 6
BX_KEY_KP_HOME | Numeric Keypad 7
BX_KEY_KP_UP | Numeric Keypad 8
BX_KEY_KP_PAGE_UP | Numeric Keypad 9
BX_KEY_KP_INSERT | Numeric Keypad 0
BX_KEY_KP_DELETE | Numeric Keypad .
BX_KEY_KP_ENTER | Numeric Keypad Enter
BX_KEY_KP_MULTIPLY | Numeric Keypad *
BX_KEY_KP_DIVIDE | Numeric Keypad /
BX_KEY_UP | UpArrow
BX_KEY_DOWN | DownArrow
BX_KEY_LEFT | LeftArrow
BX_KEY_RIGHT | RightArrow
BX_KEY_WIN_L | Left Windows
BX_KEY_WIN_R | Right Windows
BX_KEY_MENU | Menu
BX_KEY_ALT_SYSREQ | Alt-Sysreq
BX_KEY_CTRL_BREAK | Ctrl-Break
BX_KEY_INT_BACK | Internet - back
BX_KEY_INT_FORWARD | Internet - forward
BX_KEY_INT_STOP | Internet - stop
BX_KEY_INT_MAIL | Internet - mail
BX_KEY_INT_SEARCH | Internet - search
BX_KEY_INT_FAV | Internet - favorites
BX_KEY_INT_HOME | Internet - home
BX_KEY_POWER_MYCOMP | Powerkeys - my computer
BX_KEY_POWER_CALC | Powerkeys - calculator
BX_KEY_POWER_SLEEP | Powerkeys - sleep
BX_KEY_POWER_POWER | Powerkeys - power
BX_KEY_POWER_WAKE | Powerkeys - wake

## Using Bochs

After starting Bochs either from the command prompt or the OS shell, the following steps are done before the simulation is running.

1. parse command line (except bochsrc options)

2. load selected config file (bochsrc) or search for the default one

3. parse remaining command line options (bochsrc syntax)

4. initialize configuration interface

5. enter start menu / dialog (unless quick start mode is enabled)

6. initialize all parts of the simulator

7. enter debugger prompt / dialog (if present)

8. enter the simulation loop

During simulation, Bochs usually generates more or less log output. By default, it is sent to the console, otherwise to the specified log file. The amount of output can be controlled with the log options in bochsrc, the start menu and the runtime configuration.

Under certain conditions Bochs can cause a panic and usually asks the user what to do. If such a panic happens during startup, it is mostly a configuration or permission problem and we recommend to quit Bochs and to review the bochsrc options used.

To quit the simulation, the "power" button in the Bochs headerbar should be used, unless the guest OS has the capability to turn off the computer (APM or ACPI).

If a Bochs runtime issue cannot be fixed by configuration changes and it has not yet been reported in the &devlist; or the SF trackers for Bochs, it should be reported in the mailing list or the SF bug tracker for the Bochs project.

### Command line arguments

The following table shows the arguments that can be used on the command line. For other arguments, see section bochsrc.

### command line arguments

Argument | Description
-q | quick start (skip configuration interface)
-f `filename` | specify configuration file
-log `filename` | specify Bochs log file
-dbglog `filename` | specify Bochs internal debugger log file
-n | don't try to load a configuration file
-benchmark `N` | run Bochs in benchmark mode for N millions of emulated ticks
-dumpstats `N` | dump Bochs stats every N millions of emulated ticks
-r `path` | specify path for restoring state
-unlock | unlock Bochs images leftover from previous session
-noconsole | disable console window (Windows only)
--help | display help message and exit
--help features | display available features / devices and exit
--help cpu | display supported CPU models and exit (CPU level > 4 only)

These arguments are handled directly after starting Bochs. The next step is to load a default or specified configuration file (unless disabled with -n). Then the rest of the command line (`bochsrc` options) is parsed. This is done after reading the configuration file so that the command line arguments can override the settings from the file.

### Search order for the configuration file

If no configuration file is specified on the command line and config file loading is not disabled, Bochs searches for a default configuration file. This is the search order:

1. `.bochsrc` in the current directory

2. `bochsrc` in the current directory

3. `bochsrc.txt` in the current directory

4. (win32 only) `bochsrc.bxrc` in the current directory

5. (Unix only) `.bochsrc` in the user's home directory

6. (Unix only) `bochsrc` in the `/etc` directory

### The configuration interface 'textconfig'

The configuration interface 'textconfig' is the text mode version of the Bochs configuration system. It is a series of menus (using stdin/stdout) that allows you to edit all the settings that control Bochs' behavior. If you do not write a config_interface line, Bochs will choose it as the default for you (unless Bochs is compiled for Win32 or wxWidgets only). If the GUI console is available at runtime, textconfig switches the display to text mode 80 x 25 and restores the simulation screen afterwards.

It consists of these three parts:

- the start menu

- the headerbar buttons

- the runtime configuration

On Win32 (without wxWidgets) the default configuration interface 'win32config' is very similar, but it presents GUI dialogs instead of text menus.

#### The start menu

If you start Bochs without the quickstart argument (-q), the Bochs configuration main menu appears:

    ------------------------------
    Bochs Configuration: Main Menu
    ------------------------------

    This is the Bochs Configuration Interface, where you can describe the
    machine that you want to simulate.  Bochs has already searched for a
    configuration file (typically called bochsrc.txt) and loaded it if it
    could be found.  When you are satisfied with the configuration, go
    ahead and start the simulation.

    You can also start Bochs with the -q option to skip these menus.

    1. Restore factory default configuration
    2. Read options from...
    3. Edit options
    4. Save options to...
    5. Restore the Bochs state from...
    6. Begin simulation
    7. Quit now

    Please choose one: [5]

Here you can load, edit and save the configuration and finally start the simulation. It is possible to start Bochs without a config file and to edit all the settings using the item "Edit options". Don't forget to save the configuration if you want to use this setup for another Bochs session.

#### The Bochs headerbar

The headerbar appears on top of the Bochs simulation window. Here you can control the behavoiur of Bochs at runtime if you click on one of these buttons:

- floppy buttons

  Here you can toggle the status of the floppy media (inserted/ejected). Bochs for win32 presents you a small dialog box for changing the floppy image. You can setup floppy drives using floppya/floppyb option.

- CD-ROM button

  Here you can toggle the media status of the first CD-ROM drive (inserted/ejected). CD-ROM drives can be set up using ata(0-3)-master/-slave option. On some platforms this button brings a up a small dialog box for changing the CD-ROM image.

- mouse button

  Here you can enable the creation of mouse events by the host. Once mouse events are captured, you cannot reach the button anymore, in order to disable capturing again. By default, you can enable and disable the mouse capture pressing the CTRL key and the third (middle) mouse button. See the mouse option parameter 'toggle' for other methods to toggle the mouse capture.

  Changing the mouse capture at runtime is not supported by all display libraries, but it is already present on RFB, SDL, SDL2, VNCSRV, Win32, wxWidgets and X11.

  Support for 2 button mouse to toggle the capture mode not yet complete - using another toggle method is recommended in that case.

- user button

  Press this button if you want to send the keyboard shortcut defined with the `user_shortcut` parameter of the keyboard option to the guest. Depending on the used display_library option, it may even be possible to edit the shortcut before sending it.

- copy button

  The text mode screen text can be exported to the clipboard after pressing this button. The button has no effect in graphics mode.

- paste button

  Text in the clipboard can also be pasted, through Bochs, to the guest OS, as simulated keystrokes. Keyboard mapping must be enabled to make this feature work.

- snapshot button

  Press this button if you want to save a snapshot of the Bochs screen. All text and graphics modes are now supported. If GUI dialogs are supported (e.g. on win32) Bochs presents you a "Save as..." dialog box to specify the filename. In text modes the formats BMP and TXT are supported depending on file extension. Platforms without GUI dialogs are using the fixed filenames "snapshot.txt" or "snapshot.bmp".

- config button

  This button stops the Bochs simulation and starts the runtime configuration. (see below).

- reset button

  Press this button to trigger a hardware reset.

- suspend button

  Press this button to save current simulation state to a disk. The simulation could be restored back using bochs -r command. For more details read the Save and restore simulation section.

- power button

  This button stops the simulation and quits Bochs.

Some of these features may not be implemented or work different on your host platform.

#### Command mode

When using 'sdl', 'sdl2', 'win32' or 'x' as the `display_library`, the option 'cmdmode' enables the "command mode" support. If enabled, pressing the F7 key will enter 'command mode' (shown in the info item of the statusbar); the next key that is pressed will exit command-mode. When in command-mode, if the pressed key is in the list below, the corresponding action will be performed. With the exception of F7, any key pressed while in command-mode will not be received by the OS running in Bochs.

#### Supported keys

Key | Action
a | Press the Floppy A button
b | Press the Floppy B button
c | Press the Copy button
SHIFT + c | Press the Config button
f | Toggle windowed / fullscreen mode (sdl, sdl2 and win32 only)
p | Press the Paste button
SHIFT + p | Press the Power button
r | Press the Reset button
s | Press the Snapshot button
SHIFT + s | Press the Suspend button
u | Press the User button
F7 | Send F7 keypress to emulation

In fullscreen mode (sdl, sdl2, win32) some handlers do not bring up a dialog box. The floppy buttons just toggle the status, the snapshot feature uses the hardcoded file name and the user button sends the configured shortcut.

#### The runtime configuration

If you want to change certain settings at runtime, you have to press the "config" button in the headerbar. The simulation stops and the runtime menu appears on the console window / xterm or the Bochs GUI console (if available).

    ---------------------
    Bochs Runtime Options
    ---------------------
    1. Floppy disk 0: /dev/fd0, size=1.44M, inserted
    2. Floppy disk 1: floppyb.img, size=1.44M, inserted
    3. 1st CD-ROM: (master on ata1) /dev/cdrom, ejected
    4. 2nd CD-ROM: (slave on ata1) /dev/cdrecorder, ejected
    5. 3rd CD-ROM: (not present)
    6. 4th CD-ROM: (not present)
    7. (not implemented)
    8. Log options for all devices
    9. Log options for individual devices
    10. Instruction tracing: off (doesn't exist yet)
    11. USB runtime options
    12. Misc runtime options
    13. Continue simulation
    14. Quit now

    Please choose one:  [13]

In the runtime configuration you can change the floppy/CD-ROM image or device, change the log options or adjust some other settings. If you have trouble with a specific device, you can change the log options for this device only to get more information (e.g. report debug messages).

### Pre-defined CPU models

If Bochs is compiled with cpu level 5 or higher the CPUID opcode is supported and it can return some information about the cpu model and its features. When using a pre-defined CPU model in Bochs the features reported by CPUID are set up according to the model's specification. The following table shows all available CPU models with a short description. The amount of choices depends on the CPU features enabled at compile time (3rd column).

### Bochs CPU models

Value | Description | Required Features
bx_generic | Default Bochs CPU configured with CPUID option | cpu level 5
pentium | Intel Pentium (P54C) | cpu level 5
pentium_mmx | Intel Pentium MMX | cpu level 5
amd_k6_2_chomper | AMD-K6(tm) 3D processor (Chomper) | cpu level 5
p2_klamath | Intel Pentium II (Klamath) | cpu level 6
p3_katmai | Intel Pentium III (Katmai) | cpu level 6
p4_willamette | Intel(R) Pentium(R) 4 (Willamette) | cpu level 6
core_duo_t2400_yonah | Intel(R) Core(TM) Duo CPU T2400 (Yonah) | cpu level 6
atom_n270 | Intel(R) Atom(TM) CPU N270 | cpu level 6
p4_prescott_celeron_336 | Intel(R) Celeron(R) 336 (Prescott) | cpu level 6, x86-64
athlon64_clawhammer | AMD Athlon(tm) 64 Processor 2800+ (Clawhammer) | cpu level 6, x86-64
athlon64_venice | AMD Athlon(tm) 64 Processor 3000+ (Venice) | cpu level 6, x86-64
turion64_tyler | AMD Turion(tm) 64 X2 Mobile TL-60 (Tyler) | cpu level 6, x86-64
phenom_8650_toliman | AMD Phenom X3 8650 (Toliman) | cpu level 6, x86-64
core2_penryn_t9600 | Intel Mobile Core 2 Duo T9600 (Penryn) | cpu level 6, x86-64
corei5_lynnfield_750 | Intel(R) Core(TM) i5 750 (Lynnfield) | cpu level 6, x86-64
corei5_arrandale_m520 | Intel(R) Core(TM) i5 M 520 (Arrandale) | cpu level 6, x86-64
corei7_sandy_bridge_2600k | Intel(R) Core(TM) i7-2600K (Sandy Bridge) | cpu level 6, x86-64, avx
zambezi | AMD FX(tm)-4100 Quad-Core Processor (Zambezi) | cpu level 6, x86-64, avx
trinity_apu | AMD A8-5600K APU (Trinity) | cpu level 6, x86-64, avx
ryzen | AMD Ryzen 7 1700 | cpu level 6, x86-64, avx
corei7_ivy_bridge_3770k | Intel(R) Core(TM) i7-3770K CPU (Ivy Bridge) | cpu level 6, x86-64, avx
corei7_haswell_4770 | Intel(R) Core(TM) i7-4770 CPU (Haswell) | cpu level 6, x86-64, avx
broadwell_ult | Intel(R) Processor 5Y70 CPU (Broadwell) | cpu level 6, x86-64, avx
corei7_skylake_x | Intel(R) Core(TM) i7-7800X CPU (Skylake) | cpu level 6, x86-64, avx
corei3_cnl | Intel(R) Core(TM) i3-8121U CPU (Cannonlake) | cpu level 6, x86-64, avx
corei7_icelake_u | QuadCore Intel Core i7-1065G7 (IceLake) | cpu level 6, x86-64, avx
tigerlake | 11th Gen Intel(R) Core(TM) i5-1135G7 (TigerLake) | cpu level 6, x86-64, avx

### Save and restore simulation

Bochs has now full save/restore support. The state of cpu(s), memory, devices and hard drive images

The disk image mode "vvfat" does not support save/restore. All other disk image modes copy the whole image or the file containing changes (journal). This may take some time, so be patient when using this feature.

can be saved. When running Bochs there will be a button in the header bar called "Suspend". Depending on config interface and GUI there will be a prompt where you can enter a path to an existing directory or a GUI folder selection dialog box. It is possible to save the state at any time, but we recommend to do it when the simulation is idle. After pressing OK/Enter, Bochs will save a set of files into the selected folder. It is possible to continue after saving the state, but when using the restore function in a new Bochs session, all changes after this checkpoint will be lost.

To restore the saved simulation state, you can select the restore function in the text mode start menu or specify the restore path at the command line:

    bochs -r /path/to/save-restore-data

Then Bochs will start up using the saved configuration and log options, restores the state of the hardware and begins the simulation. In the restore mode Bochs will ignore bochsrc options from the command line and does not load a normal config file.

### Using sound

#### Sound basics

Bochs supports two types of soundcards (SB16 ISA and ES1370 PCI) and the legacy PC speaker. The lowlevel sound interface provides a set of functions for wave (PCM) input / output and MIDI output using the host sound system. A driver must not implement all of these functions. The following table shows the supported drivers and their features.

#### Sound lowlevel modules

Name | Description | Wave input | MIDI output
alsa | use the default ALSA PCM device and the default ALSA sequencer on Linux | Yes | Yes
oss | use the Open Sound System on Linux and FreeBSD | Yes | Yes
osx | for output on Mac OS 9 and Mac OSX | No | Yes
sdl | for wave output on platforms supported by SDL (1.2.x or 2.x) | No | No
win | for output to the midi and wave mapper of Windows | Yes | Yes

These special values are also valid for the sound driver:

- `default` - select platform-default sound driver.

- `file` - wave and MIDI output to file(s)

- `dummy` - no output at all

When compiling Bochs, the lowlevel sound support is activated if one of the soundcards is enabled (`--enable-sb16` or `--enable-es1370`). The configure script detects the available drivers and sets up a platform-default one.

At runtime the lowlevel sound module will be loaded automatically if one of the sound devices are enabled in the `bochsrc` file. The drivers and devices for wave input / output and MIDI output must be set up with the sound option.

#### The PC speaker

The PC speaker is connected to the PIT 8254 timer #2 and generates a square wave beep with a frequency depending on the timer value. In Bochs the speaker is a separate plugin that is controlled by the two events "beep on" and "beep off". The "beep on" event is also called when the frequency changes while turned on.

The destination for the speaker output can be selected with the `mode` parameter of the speaker option. Three choices are available:

- `sound` : the beep is generated by the square wave generator which is a part of the lowlevel sound support.

- `system` : only available on Linux and Windows. On Linux /dev/console is used for output and on Windows the Beep() function.

- `gui` : forwards the beep to the related GUI methods (currently only used by the Carbon GUI).

#### SB16 runtime configuration

Most of the SB16 configuration parameters are available in the runtime configuration menu or dialog. In addition to this, there is a small program called `SB16CTRL` to change emulation settings from inside the simulation.

##### Runtime options

Unlike other devices, the SB16 emulation has its own logfile and a loglevel parameter to control what should be printed there. Both the `log` file and `loglevel` parameters can be changed at runtime. See the sb16 bochsrc option for details.

The output parameters `midimode`, `midifile`, `wavemode` and `wavefile` are also available at runtime.

The `dmatimer` parameter controls the DMA timing for wave (PCM) input and output. When you get non-continuous sound, this value can be ajusted to fix this. This needs a reasonably correct setting for the cpu: ips option.

##### SB16CTRL

The source for the SB16CTRL program that is used to modify the runtime behavior of the SB16 emulation is included in `misc/sb16/`. It is a C program that can be run from inside the emulation.

It currently supports the following commands:

##### Supported options for `sb16ctrl`

Option | Description
`-i `number`` | Show the selected emulator info string, e.g. `sb16ctrl -i 3` to show how many patch translations are active.
`-t `six numbers`` | Load a translation into the translation table. The numbers are: "OldBankMSB,OldBankLSB,OldProgram,NewBankMSB,NewBankLSB,NewProgram". All values can be 0..127 or 255. 255 for "Old" values means match any and for "New" values means don't change, e.g. `sb16ctrl -t 255,255,0,255,255,32` to change patch 0 (Piano) to patch 32 (Acoustic Bass).
`-r` | Reset the patch translation table e.g. `sb16ctrl -r`.
`-m `some numbers`` | Upload the given numbers to the midi output device. Note that it should be a complete midi message, and also that it is subject to patch translation, e.g. `sb16ctrl -m 0x80,64,0` to send a note-off message to channel 0.
`-f `filename`` | Read in a file and execute the commands in it. These have the same format as the above commands, except that they don't have the dash "-" in front of them. Comment lines are supported and start with a hash sign "#".
`-h` | Show a brief summary of the commands.

All numbers can be valid parameters to the `strtol()` function, so hex and octal notation is fine. They have to be delimited by either commas "," or slashes "/", spaces are not allowed.

The command line can have any number of commands. However, if none are given, "-f -" is assumed, which means commands are taken from stdin.

### USB configuration

The USB configuration allows you to add, delete, or modify an existing USB device.

The 'device' field may contain one of the following items:

#### Mouse

By default, this emulates a 3-button mouse. After a reset, it is set up to send the Report Protocol report and consists of a 4-byte report:

    byte 0:  00000BBB  Bits 7:3 are zero
                       Bit 2 is button 3
                       Bit 1 is button 2
                       Bit 0 is button 1
    byte 1:  XXXXXXXX  8-bit X displacement (-127 -> 127)
    byte 2:  YYYYYYYY  8-bit Y displacement (-127 -> 127)
    byte 3:  WWWWWWWW  8-bit Wheel displacement (-127 -> 127)

Using the 'model:xxxx" parameter, you can set the mouse to report a different type packet. See below.

This device may be used on all Host Controller types using a speed of 'low', 'full', or 'high'. (see model 'm388phy')

    usb_uhci: enabled=1, port1=mouse, options1="speed:low"              # default report packet shown above
    usb_ohci: enabled=1, port1=mouse, options1="speed:full, model:m228" # 3-byte report packet, 2 button, 8-bits
    usb_ehci: enabled=1, port1=mouse, options1="speed:high, model:m338" # 3-byte report packet, 3 button, 8-bits
    usb_xhci: enabled=3, port3=mouse, options1="speed:full, model:m3312" # 3-byte report packet, 3 button, 12-bits

The model: parameter may have one of the following names: 'm228', 'm338', 'm3312', 'm3316', 'm338phy', or 'm33xDebug'.

##### model: m228

Returns the 4-byte packet shown below.

    byte 0:  00000001  Report ID (1)
    byte 1:  000000BB  Bits 7:2 are zero
                       Bit 1 is button 2
                       Bit 0 is button 1
    byte 2:  XXXXXXXX  8-bit X displacement (-128 -> 127)
    byte 3:  YYYYYYYY  8-bit Y displacement (-128 -> 127)

This model uses a Report ID, and prepends this byte ID to the Report Packet. (See byte 0 above)

##### model: m338

Returns the 4-byte packet shown at bochsopt-usb-mouse above. This is the default model and will be used if the `model:` parameter is not used.

##### model: m338phy

Returns the default 4-byte packet, same as `m338`, but includes a HID Physical Descriptor and associated Designator entries.

To make the Bochs source code simpler, this model must be used with low- and full-speed devices only.

Note that some Guests, including (older) widely used commercial Guests, see an HID Report with Physical indicators (Designator Min/Max) as invalid and won't continue to use the mouse.

##### model: m3312

Returns the 5-byte packet shown below.

    byte 0:  00000BBB  Bits 7:3 are zero
                       Bit 2 is button 3
                       Bit 1 is button 2
                       Bit 0 is button 1
    byte 1:  XXXXXXXX  12-bit X displacement (-2048 -> 2047)
    byte 2:  YYYYXXXX
    byte 3:  YYYYYYYY  12-bit Y displacement (-2048 -> 2047)
    byte 4:  WWWWWWWW  8-bit Wheel displacement (-128 -> 127)

##### model: m3316

Returns the 6-byte packet shown below.

    byte 0:  00000BBB  Bits 7:3 are zero
                       Bit 2 is button 3
                       Bit 1 is button 2
                       Bit 0 is button 1
    byte 1:  XXXXXXXX  16-bit X displacement (-32768 -> 32767)
    byte 2:  XXXXXXXX
    byte 4:  YYYYYYYY  16-bit Y displacement (-32768 -> 32767)
    byte 5:  YYYYYYYY
    byte 6:  WWWWWWWW  8-bit Wheel displacement (-128 -> 127)

##### model: m33xDebug (Debug model)

This report is deliberately irregular by design, so that a Guest can test its HID Report Descriptor Parser.

- - the button fields are not consecutive and are at arbitrary positions in the report.

- - the coords fields are not byte aligned or consecutively spaced.

- - the coords fields are of an irregular size, each a different size.

- - there are padding fields between entries that `do not` align the next field on a byte boundary.

- - this also uses the push/pop mechanism to test the function of your parser.

Again, this is deliberate. A correctly written parser will extract the neccessary fields no matter the irregularity.

Returns the 5-byte packet shown below.

    byte 0:  YYYYYYY0  10-bit Y displacement (-512 -> 511)
    byte 1:  WWWW0YYY  8-bit Wheel displacement (-128 -> 127)
    byte 2:  0B00WWWW  bit 6 is Button #2 (right button)
    byte 3:  XXXXX0B0  9-bit X displacement, bit 1 is Button #1 (left button)
    byte 4:  0B00XXXX  bit 6 is Button #3 (middle button)

Please note that this model is not for normal use. It is `intentionally` irregular, and its purpose is to test an HID Parser.

##### mouse: misc

Please note that most physical USB mice will be 'low-speed' only.

#### Keyboard

This emulates a standard keyboard. Key press and release codes are translated from the Host's keyboard to the Guest as USB Interrupt packets.

After a reset, it is set up to send the Report Protocol report and consists of a 8-byte report:

    byte 0:  MMMMMMMM  Modifier Keys
                        Bit 7 = Right GUI
                        Bit 6 = Right Alt
                        Bit 5 = Right Shift
                        Bit 4 = Right Ctrl
                        Bit 3 = Left GUI
                        Bit 2 = Left Alt
                        Bit 1 = Left Shift
                        Bit 0 = Left Ctrl
    byte 1:  00000000  Reserved
    byte 2:  xxxxxxxx  Key Code 1
    byte 3:  xxxxxxxx  Key Code 2
    byte 4:  xxxxxxxx  Key Code 3
    byte 5:  xxxxxxxx  Key Code 4
    byte 6:  xxxxxxxx  Key Code 5
    byte 7:  xxxxxxxx  Key Code 6

The keyboard expects the following 'Output' packet when modifying the Num Lock, Caps Lock, and Scroll Lock states:

    byte 0:  00000LLL  Lock States
                        Bit 2 = Scroll Lock
                        Bit 1 = Caps Lock
                        Bit 0 = Num Lock

This device may be used on all Host Controller types using a speed of 'low', 'full', or 'high'.

    usb_uhci: enabled=1, port1=keyboard, options1="speed:low"
    usb_ohci: enabled=1, port1=keyboard, options1="speed:full"
    usb_ehci: enabled=1, port1=keyboard, options1="speed:high"
    usb_xhci: enabled=3, port3=keyboard, options1="speed:full"

Please note that most physical USB keyboards will be 'low-speed' only.

#### Keypad

This emulates a numeric keypad. Key press and release codes are translated from the Host's keyboard to the Guest as USB Interrupt packets.

Only the keys that are on a standard 104-key keyboard's keypad are returned. These keys are the USB HID Usage ID's `0x53` to `0x63` and are handled by the USB keypad and are sent to the Guest via USB Interrupt packets. (see the 'Keyboard' item above for the format of this packet).

All remaining key press and release events are handled by the underlining keyboard emulation, usually the AT/PS2 keyboard emulation. Therefore, the guest will still receive other keypress events. Only the key range noted before will be sent via the USB emulation.

This device may be used on all Host Controller types using a speed of 'low', 'full', or 'high'.

    usb_uhci: enabled=1, port1=keypad, options1="speed:low"
    usb_ohci: enabled=1, port1=keypad, options1="speed:full"
    usb_ehci: enabled=1, port1=keypad, options1="speed:high"
    usb_xhci: enabled=3, port3=keypad, options1="speed:full"

Please note that most physical USB keypads will be 'low-speed' only.

#### Tablet

This emulates a 3-button mouse. After a reset, it is set up to send the Report Protocol report and consists of a 6-byte report:

    byte 0:  00000BBB  Bits 7:3 are zero
                       Bit 2 is button 3
                       Bit 1 is button 2
                       Bit 0 is button 1
    byte 1:  XXXXXXXX  8-bit X Displacement (low byte)
    byte 2:  XXXXXXXX  8-bit X Displacement (high byte)
    byte 3:  YYYYYYYY  8-bit Y Displacement (low byte)
    byte 4:  YYYYYYYY  8-bit Y Displacement (high byte)
    byte 5:  ZZZZZZZZ  8-bit Z Displacement

Please note that the X and Y Displacement values are absolute, not relative values.

This device may be used on all Host Controller types using a speed of 'low', 'full', or 'high'.

    usb_uhci: enabled=1, port1=tablet, options1="speed:low"
    usb_ohci: enabled=1, port1=tablet, options1="speed:full"
    usb_ehci: enabled=1, port1=tablet, options1="speed:high"
    usb_xhci: enabled=3, port3=tablet, options1="speed:full"

Please note that most physical USB tablets will be 'low-speed' only.

#### Disk/CD-ROM

This emulates a media device in the form of a hard-drive or CD-ROM. By default, the emulation uses the "Bulk-only" transport, also known as "Bulk/Bulk/Bulk". For high- and super-speed devices, you can specify the "UASP" protocol, also known as "USB Attached SCSI Protocol".

This device may be used on all Host Controller types using a speed of 'full', 'high', or 'super'.

    usb_uhci: enabled=1, port1=disk, options1="speed:full, path:hdd.img"  # defaults to the BBB protocol
    usb_ohci: enabled=1, port1=disk, options1="speed:full, path:hdd.img"
    usb_ehci: enabled=1, port1=disk, options1="speed:high, path:hdd.img"
    usb_ehci: enabled=1, port1=disk, options1="speed:high, path:hdd.img, proto:bbb"
    usb_ehci: enabled=1, port1=disk, options1="speed:high, path:hdd.img, proto:uasp"
    usb_xhci: enabled=3, port1=disk, options3="speed:full, path:hdd.img"
    usb_xhci: enabled=3, port1=disk, options3="speed:high, path:hdd.img, proto:bbb"
    usb_xhci: enabled=3, port1=disk, options3="speed:high, path:hdd.img, proto:uasp"
    usb_xhci: enabled=1, port1=disk, options1="speed:super, path:hdd.img, proto:bbb"
    usb_xhci: enabled=1, port1=disk, options1="speed:super, path:hdd.img, proto:uasp"

An image format, similar to the ATA option, can be used. Replace 'mode' below with the desired format.

    usb_xhci: enabled=3, port1=disk, options3="speed:high, path:mode:hdd.img, proto:bbb"
    usb_xhci: enabled=3, port1=disk, options3="speed:high, path:mode:hdd.img, proto:uasp"

To emuate a CD-ROM, replace 'disk' in the examples above with 'cdrom', and adjust the 'path' accordingly.

Specifying 'proto:uasp' does not guarantee that the Guest will use that protocol. See a previous section for more information.

Please note that this device is not allowed as a low-speed only device. Low-speed should be specified.

#### Floppy

This emulates a media device in the form of an external Floppy drive. By default, the emulation uses the "Control/Bulk/Interrupt" transport, aka "CBI". Bochs can be re-compiled to use the "Control/Bulk" transport, aka "CB".

This device may be used on all Host Controller types using a speed of 'full'.

    usb_uhci: enabled=1, port1=floppy, options1="speed:full, path:floppy.img"
    usb_ohci: enabled=1, port1=floppy, options1="speed:full, path:floppy.img, model:teac"
    usb_ehci: enabled=1, port1=floppy, options1="speed:full, path:floppy.img, model:teac"
    usb_xhci: enabled=1, port3=floppy, options3="speed:full, path:floppy.img"

An image format, similar to the ATA option, can be used. Replace 'mode' below with the desired format.

    usb_uhci: enabled=1, port1=floppy, options1="speed:full, path:mode:floppy.img"

The 'model:teac' option can be used to emulate that specific model, else a default model will be used. If a guest does not see the attached floppy, try specifying the 'teac' model.

Please note that this device is a full-speed only device. No other speed should be specified.

#### Printer

This emulates a simple USB printer. All data sent to the printer will be appended to a specified file on the Host.

This device may be used on all Host Controller types using a speed of 'full'.

    usb_uhci: enabled=1, port1=printer, options1="speed:full, file:printdata.bin"
    usb_ohci: enabled=1, port1=printer, options1="speed:full, file:printdata.bin"
    usb_ehci: enabled=1, port1=printer, options1="speed:full, file:printdata.bin"
    usb_xhci: enabled=1, port3=printer, options3="speed:full, file:printdata.bin"

Please note that this device is a full-speed only device. No other speed should be specified.

#### Hub

This emulates a full-speed 4-port external hub. The number of ports can be changed, with a range of 2 to 8.

This device may be used on all Host Controller types using a speed of 'full'.

    usb_uhci: enabled=1, port1=hub, options1="speed:full"
    usb_ohci: enabled=1, port1=hub, options1="speed:full, ports:4"
    usb_ehci: enabled=1, port1=hub, options1="speed:full, ports:6"
    usb_xhci: enabled=1, port1=hub, options1="speed:full, ports:8"

At startup, no device is attached to this hub. However, after start up, using the runtime interface, a device can be attached to any or all of the ports.

Any device attached to this hub (via the runtime interface), must be the same as or less than the hub's current speed (which is currently only full-speed). Any device plugged into a hub, no matter its max speed, can only function at or below the speed of the hub it is attached to.

Please note that this device is a full-speed only device. No other speed should be specified.

#### Packet Capture

All devices may use the 'pcap' option to send all data to a Packet Capture formatted file.

    usb_uhci: enabled=1, port1=hub, options1="speed:full, pcap:outfile.pcap"

This file is formatted to be used with Linux' usbmon and utilities such as Wire Shark.

Please note that this option will not capture any data that would normally flow through an external hub, so if you use the 'pcap' option for a hub, as with the example above, only the hub's data is captured, not the device(s) attached to it.

#### Signaling an Over-Current event

During emulation, using the runtime configuration, you can signal an over-current event on any device using the 'over-current' checkbox (GUI) or text configuration option. This will signal an over-current event on the Host Controller for that port.

Over-current is considered undefined on the UHCI, though Intel 430TX and later controllers may have implemented over-current via two previously unused bits.

#### Notes

- All devices allow the 'debug' option to be used. This turns on the BX_DEBUG() logging for that device.

      usb_uhci: enabled=1, port1=hub, options1="speed:full, debug"

- You can wrap options in double-quotes in your bochsrc file. However, the runtime config interface has problems when double-quotes are used. Therefore, don't use them in the runtime configuration interface.

## Common problems and what to do about them (Troubleshooting)

### Bochs panics! What can I do?

Bochs does a very good job in emulating an x86 compatible computer, however, it does not (yet) include a full (100%) emulation of every possible instruction, (BIOS) function call or (hardware) device. Thus, in case something unusual happens, either a not-so-common call to some (BIOS) function or device by some software running inside of it, Bochs has two possibilities to react: If the command doesn't look important (mainly happens only to non-implemented functions in the BIOS), a notice is logged to the log file and the emulation continues. If, however, the command looks important, Bochs panics, because the software being emulated might depend on the successful execution of the given instruction or behavior of the device.

A panic does not always mean that the software won't run inside of Bochs, as the software might just be probing the computer for the presence of some instruction/device, and in case it is not found, it simply won't be used at all, by the software.

You can tell Bochs what to do in case of a panic, by re-configuring the panic option. If you change the action to "ask", Bochs reports what has happened and asks you what to do. The appearance of the "ask" feature depends on the display library used and the platform. Some display libraries don't support it at all.

Some of the device names reported in the panic message are abbreviations, since the length of the 'prefix' is limited to 6 characters. The log function module table may help you finding out the name of the device that caused the panic. It also gives you a short description of the module.

### Mouse behavior, enabling and disabling

Refer to headerbar for information on how to enable or disable the mouse inside of Bochs at run-time.

The mouse cursor movement speed mostly doesn't match the real movement. This is caused by the variable emulation speed (from the user's point of view) and the relative mouse position data that standard PS/2, serial or USB mice are generating. The alternative is the USB tablet emulation that generates absolute mouse position data. We recommend to use it with the display libraries 'rfb' and 'vncsrv'.

### Text-mode is broken in some ancient DOS program

If you are using a program written for DOS which seems to use the text-mode but doesn't display the text properly, you can try the other VGA BIOS, either `VGABIOS-lgpl-latest` or `VGABIOS-elpin-2.40`, see the vgaromimage option.

&NEEDHELP; Maybe it is a bug in the LGPL VGA BIOS, but for now, it seems to work.

## Feedback and Support

### The Bochs project on SourceForge

The Bochs project page on SourceForge provides these features:

- Project summary page with screenshots and download statistics

- Download area for Bochs release packages and disk images

- Mailing list archives

- Source code browser

- Tickets section (bug reports, patches, feature requests etc.)

- Discussion boards (e.g. "Help" and "Open Discussion")

- Project news page (used for release announcements)

#### SourceForge tickets section (bug and patch trackers)

There are some requirements when submitting bug reports, patches, and feature requests for Bochs to make it easier to reproduce bugs and test patches.

##### Reporting errors from Bochs compilation

When reporting errors while building Bochs to the &devlist; or the SF bug tracker for the Bochs project, this information is required to fix the issue:

- host platorm / build environment

- Bochs release version or SVN revision

- configure options used

- full error message

- config.log output if configure failure

- source file name and line number if compile error

Before reporting us the issue, make sure that a similar one hasn't been already reported or someone created a patch to fix it. If you are familiar with C++ and you can write some code to fix your problem, you can post it in the &devlist; or submit the patch in SF patch tracker for Bochs.

##### Reporting Bochs runtime issues

If Bochs does not work properly (e.g. panic, segfault, malfunction of emulated device) we need some information to find out what's going on:

- Bochs version used (version number if binary release / SVN revision if self-compiled)

- host platorm / build environment (if self-compiled)

- bochsrc options used

- error message (if panic or program termination)

- log file output (related section only if too big)

##### Submitting a patch for Bochs

Patches for Bochs should be provided in the "unified diff" format. In addition to the patch file and a detailed description this information is required:

- patch applies to Bochs release version / SVN revision

- test case (if required)

When you are are interested in writing a patch to fix bugs or add new features, you should have a look at the developer documentation. For some parts of the Bochs code we have already written some basic information.

### Mailing Lists

The Bochs community uses three mailing lists to communicate, called bochs-developers, bochs-cvs and bochs-announce.

#### bochs-developers mailing list

Bochs-developers is the forum for all Bochs discussions and questions. On average, subscribers get between five and ten messages per day. There are about 350 subscribers. If this sounds like too much email, maybe the bochs-announce list is more appropriate for you. Anyone may join the list, unless they abuse it of course.

To subscribe, go to the Bochs-Developers Info Page and type your email address and a password into the web form and click `Subscribe`. In a few minutes you will get a confirmation email. Follow the directions in the email to complete the subscription process. To unsubscribe, go to the same page and type your email address in the blank at the bottom and click on `Edit Options`. Then type your password and click `Unsubscribe`.

Once you have subscribed, you can write to bochs-developers@lists.sourceforge.net to send a message to everyone on the list. While it's possible to post without being a subscriber, it's not recommended. If you aren't a subscriber, you might miss the response to your question.

Archive of bochs-developers messages

#### bochs-announce mailing list

Bochs-announce is a moderated, low-traffic list which carries only periodic announcements of Bochs releases and important events. If you have a very important and truly relevant Bochs announcement, you can try posting it to bochs-announce, but the moderator will have to approve it before it will go out. On average, bochs-announce subscribers get one or two messages per month. There are about 75 subscribers. Anyone may join the list.

To subscribe, go to the Bochs-Announce Info Page and type your email address and a password into the web form and click `Subscribe`. In a few minutes you will get a confirmation email. Follow the directions in the email to complete the subscription process. To unsubscribe, go to the same page and type your email address in the blank at the bottom and click on `Edit Options`. Then type your password and click `Unsubscribe`.

There is no need to subscribe to both lists, because all bochs-announce messages are forwarded to the developers list. If you subscribe to both, you will get 2 copies of every announcement.

Archive of bochs-announce messages

#### bochs-cvs mailing list

This is the svn commit mailinglist (a unified diff email will be sent whenever someone does a checkin in the bochs SVN repository).

Archive of bochs-cvs messages

#### Mailing List Etiquette

Here are a few guidelines for use of the Bochs mailing lists:

- Please check the documentation before asking questions, but on this list you are very UNLIKELY to get flamed and insulted for being a Bochs beginner. Sending commercial promotions to the list probably will get you some angry responses though.

- If you are having difficulty finding what you are looking for, try doing a search on Google. If you are searching for Bochs options, for example, you can use this syntax in the Google search box:

      configuration options site:bochs.sourceforge.net

  For best results, be sure not to put a space between "site:" and "bochs.sourceforge.net". Be sure to look at more than the first item on the search results.

- If you still cannot find what you are looking for, be sure you are prepared when you post your question, and post in the right forum. Be sure you include important details, such as the operating system and version of your host, and what it is you are trying to do. If you are getting errors or something is not working, summarize what you checked and what you changed. This will help isolate the problem.

- Bochs is for everyone. If you are an experienced Bochs user or developer and are helping someone else, be considerate of the other person's feelings. We share a common interest, and we need to encourage each other and be supportive.

- Also, keep in mind that messages are limited to 40K, so if you want to share a large screen shot or disk image, put it on a web or FTP site and tell people how to find it. Patches are usually small enough that they aren't a problem, especially if compressed.

- Distribution of copyrighted material, or even offers to distribute copyrighted material WILL NOT be tolerated. The Bochs Project does not distribute any software (disk images) in violation of the license agreement, and users who do so will be warned first and then blocked from the list if it happens again. As an open source project, we rely on donated services from Source Forge and other groups, and we can't afford to put them or ourselves at risk of legal action.

- It is possible to subscribe and unsubscribe by email. If you do this, you must write to bochs-announce-request or bochs-developers-request. Don't forget the "-request" part or your subscribe message will go to 300+ people.

## The Bochs internal debugger

### Using the command line debugger

You can now conditionally compile in a GDB like command line debugger, that allows you to set breakpoints, step through instructions, and other useful functions. If there isn't a command for something you believe is generally useful for the debugger, let me know and I'll implement it if possible.

This section describes how to enable and use the Bochs command line debugger. For its builtin graphical front-end please see the debugger gui section how to enable it.

To use the debugger, you must configure Bochs with the `--enable-debugger` flag. For example:

      ./configure --enable-debugger

You must use flex version 2.5.4 or greater. I have heard that version 2.5.2 will not work.

When you first start up Bochs, you will see the command line prompt

      bochs:1>

From here, you may use the following commands:

#### Execution Control

      c                           continue executing
      cont
      continue

      s     [count]               execute count instructions, default is 1
      step  [count]

      s     [cpu] [count]         for SMP simulation, execute count instructions on cpu, default is 1
      step  [cpu] [count]

      s     all [count]           for SMP simulation, execute count instructions on all cpus
      step  all [count]

      Ctrl-C                      stop execution, and return to command line prompt
      Ctrl-D                      if at empty line on command line, exit

      q                           quit debugger and execution
      quit
      exit

#### BreakPoints

      NOTE: The format of 'seg', 'off', and 'addr' in these descriptions,
            are as follows.  I don't have any way to set the current radix.

            hexidecimal:    0xcdef0123
            decimal:        123456789
            octal:          01234567

      vbreak seg:off              Set a virtual address instruction breakpoint
      vb     seg:off

      vbreak seg:off if "expr"    Set a conditional virtual address instruction breakpoint
      vb     seg:off if "expr"

      lbreak addr                 Set a linear address instruction breakpoint
      lb     addr

      lbreak addr if "expr"       Set a conditional linear address instruction breakpoint
      lb     addr if "expr"

      pbreak [*] addr             Set a physical address instruction breakpoint
      pb     [*] addr             (the '*' is optional for GDB compatibility)
      break  [*] addr
      b      [*] addr

      pbreak [*] addr if "expr"   Set a conditional physical address instruction breakpoint
      pb     [*] addr if "expr"   (the '*' is optional for GDB compatibility)
      break  [*] addr if "expr"
      b      [*] addr if "expr"

      info break                  Display state of all current breakpoints
      bpe    n                    Enable a breakpoint
      bpd    n                    Disable a breakpoint
      delete n                    Delete a breakpoint
      del    n
      d      n

#### Memory WatchPoints

      watch read  addr            Insert a read watch point at physical address addr
      watch r     addr            Insert a read watch point at physical address addr

      watch write addr            Insert a write watch point at physical address addr
      watch w     addr            Insert a write watch point at physical address addr

      watch                       Display state of current memory watchpoints

      watch stop                  Stop simulation when a watchpoint is encountered (default)
      watch continue              Do not stop simulation when a watchpoint is encountered

      unwatch addr                Remove watchpoint to specific physical address
      unwatch                     Remove all watch points

#### Manipulating Memory

      x  /nuf addr      Examine memory at linear address addr
      xp /nuf addr      Examine memory at physical address addr
         n              Count of how many units to display
         u              Unit size; one of
                          b Individual bytes
                          h Halfwords (2 bytes)
                          w Words (4 bytes)
                          g Giant words (8 bytes)
                          NOTE: these are *not* typical Intel nomenclature sizes,
                                but they are consistent with GDB convention.
         f              Printing format.  one of
                          x Print in hexadecimal
                          d Print in decimal
                          u Print in unsigned decimal
                          o Print in octal
                          t Print in binary

        n, f, and u are optional parameters.  u and f default to the last values
        you used, or to w(words) and x(hex) if none have been supplied.
        n currently defaults to 1.  If none of these optional parameters are
        used, no slash should be typed.  addr is also optional.  If you don't
        specify it, it will be the value the next address (as if you had
        specified n+1 in the last x command).

      setpmem addr datasize val    Set physical memory location of size
                                   datasize to value val.

      writemem filename addr len   dump a number of bytes of virtual memory starting from
                                   the specified linear address into a file

      loadmem filename addr        initialize virtual memory starting from the specified linear
                                   address from a file

      deref addr deep              pointer dereference. For example: get value of [[[rax]]] or ***rax: deref rax 3

      crc  addr1  addr2            Show CRC32 for physical memory range addr1..addr2

#### Info commands

      r|reg|regs|registers         List of CPU integer registers and their contents
      fp|fpu                       List of all FPU registers and their contents
      mmx                          List of all MMX registers and their contents
      sse|xmm                      List of all SSE registers and their contents
      ymm|zmm                      List of all AVX registers and their contents
      amx|tile n                   Show AMX state and TILE register contents
      sreg                         Show segment registers and their contents
      dreg                         Show debug registers and their contents
      creg                         Show control registers and their contents

      info cpu                     List of all CPU registers and their contents
      info eflags                  Show decoded EFLAGS register
      info break                   Information about current breakpoint status
      info tab                     Show paging address translation
      info idt                     Show contents of the IDT
      info gdt                     Show contents of the GDT
      info ldt                     Show contents of the LDT
      info device                  Show state of the specified device

#### Manipulating CPU Registers

      set reg = expr    Change a CPU register to value of expression.
                        Currently only general purpose registers and instruction pointer
                        are supported. You may not change eflags, segment registers,
                        floating point or SIMD registers.

        Examples: set eax = 2+2/2
                  set esi = 2*eax+ebx

      registers         List of CPU registers and their contents
      regs
      reg
      r

      calc|? expr       Evaluate an expression and display the result.
                        'expr' can reference any general-purpose, opmask and segment
                        registers, use any arithmetic and logic operations, and also
                        special ':' operator which computes the linear address of a
                        segment:offset (in real and v86 mode) or of a selector:offset
                        (in protected mode) pair. Use $ operator for dereference,
                        for example, get value of [[[rax]]] or ***rax: rax$3.

#### Disassembly commands

      disassemble start end       Disassemble instructions in given linear address
                                  range, inclusive of start, exclusive of end.
                                  Use "set $disassemble_size =" to tell
                                  debugger desired segment size.  Use a value for
                                  end of less than start (or zero) if you only
                                  want the first instruction disassembled.

      disassemble switch-mode     Switch between Intel and AT&T disassembly styles
                                  for debugger disassembler.

      disassemble size = n        Tell debugger what segment size to use when
                                  the "disassemble" command is used.  Use values
                                  of 0, 16 or 32 for n.  Value of 0 means
                                  "use segment size specified by current CS
                                  segment". Default is 0.

      set $auto_disassemble = n   Cause debugger to disassemble current instruction
                                  every time execution stops if n=1.  Default is 0.
                                  Segment size of current CPU context is used for
                                  disassembly, so the "disassemble size" variable is
                                  ignored.

      set disassemble on          The same as 'set $auto_disassemble = 1'
      set disassemble off         The same as 'set $auto_disassemble = 0'

#### Instruction tracing

      trace on                    Disassemble every executed instruction. Note
                                  that instructions which caused exceptions are
                                  not really executed, and therefore not traced.

      trace off                   Disable instruction tracing.

      trace-mem on/off            Enable/Disable memory access tracing.

#### Instrumentation

To use instrumentation features in Bochs, you must compile in support for it. You should build a custom instrumentation library in a separate directory in the "instrument/" directory. To tell configure which instrumentation library you want to use, use the `--enable-instrumentation` option. The default library consists of a set of stubs, and the following are equivalent:

      ./configure [...] --enable-instrumentation
      ./configure [...] --enable-instrumentation="instrument/stubs"

You could make a separate directory with your custom library, for example, "instrument/myinstrument", copy the contents of the "instrument/stubs" directory to it, then customize it. Use:

      ./configure [...] --enable-instrumentation="instrument/myinstrument"

#### Instrumentation commands

      instrument [command]          calls BX_INSTR_DEBUG_CMD instrumentation callback with [command]
      instrument "[command string]" calls BX_INSTR_DEBUG_CMD instrumentation callback with [command string]

#### Other Commands

    ptime

Print the current time (number of ticks since start of simulation).

    sb delta

Insert a time break point "delta" instructions into the future ("delta" is a 64-bit integer followed by "L", for example 1000L).

    sba time

Insert a time break point at "time" ("time" is a 64-bit integer followed by "L", for example 1000L).

    print-stack [num words]

Print the `num words` top 16-bit words on the stack. `Num words` defaults to 16. Only works reliably in protected mode when the base address of the stack segment is zero.

    print-string addr

prints a null-ended string from a linear address.

    bt [num_entries]

prints backtrace.

    source file

cause debugger to execute a script file

    addlyt file

cause debugger to execute a script file every time execution stops.

Example of use:

Create a script file (script.txt) with the following content

        regs
        print-stack 7
        u /10
        (*EMPTY NEW LINE)

Execute addlyt

    addlyt "script.txt"

Then, when you execute a step/DebugBreak... you will see: registers, stack and disasm.

    remlyt

stops debugger to execute the script file added previously with addlyt command.

    lyt

cause debugger to execute script file added previously with addlyt command. Use it as a refresh/context.

    modebp

Toggles CPU mode switch breakpoint.

    ldsym [global] filename [offset]

Load symbols from file `filename`. If the global keyword is added, then the the symbols will be visible in all contexts for which symbols have not been loaded. `Offset` (default is 0) is added to every symbol entry. The symbols are loaded in the current (executing) context.

The symbol file consists of zero or more lines of the format

    "%x %s"

.

    setmagicbps "cx dx bx sp bp si di"

Set new magic breakpoints. You can specify multiple at once. Using the setmagicbps command without any arguments will disable all of them Example for breaking on "XCHGW %DI, %DI" or "XCHGW %SP, %SP" execution

      setmagicbps "di sp"

    clrmagicbps "cx dx bx sp bp si di"

Clear magic breakpoints. You can specify multiple at once. Using the clrmagicbps command without any arguments will disable all of them Example for clearing "XCHGW %DI, %DI" and "XCHGW %SP, %SP"

      clrmagicbps "di sp"

    show [string]

      Toggles show symbolic info (calls to begin with).
      show - shows current show mode
      show mode     - show, when processor switch mode
      show int      - show, when interrupt is happens
      show call     - show, when call is happens
      show ret      - show, when iret is happens
      show off      - toggles off symbolic info
      show dbg-all  - turn on all show flags
      show dbg-none - turn off all show flags

#### Related links

&FIXME; For information on advanced debugger usage see the developer documentation (under construction).

### The Bochs debugger GUI

The graphical front-end for the Bochs command line debugger is available for Windows and GTK2/GTK3 hosts.

To use the GUI debugger, you must configure Bochs with the default debugger switch and the `--enable-debugger-gui` flag. For example:

      ./configure --enable-debugger --enable-debugger-gui

At runtime you need to add the value `gui_debug` to the display_library options parameter in order to use the GUI instead of the command line debugger. This example shows how to use it with the 'x' GUI:

    display_library: x, options="gui_debug"

The wxWidgets port of Bochs always uses this debugger GUI. Passing the option to the display library is not necessary, since the command line interface is not available then.

#### Overview

The GUI debugger consists of a GUI window with a menu bar, a button bar and some child windows for different purposes. Not all windows are visible at the same time.

- Register window

- Disassembly window

- MemDump window

- Output window: display internal debugger output / log output

- Input window: command prompt for entering debugger commands

- Param tree window: show the Bochs parameter tree (CPU / hardware state)

- Stack window

- Breakpoint / watchpoint window

- Command button row

- CPU button row: only available for SMP emulation

#### The register window

Typically, all the various registers are grouped by color. If you don't like the colors, they can be turned off, or modified at compile time. There are options to show or hide most register "groups", so that you can focus more strictly on the registers you are interested in (probably just the GP registers).

Yes, the XMM display shows hex in the "decimal" column -- there is more room there. Deal with it.

Doubleclicking a register attempts to change its value. Bochs may not allow you to change most registers. In future versions, more registers may be modifiable.

#### The disassembly window

Disassembly output that is autoloaded, or generated from the menu, ends up here. If the frontend cannot detect the "current instruction" in the list, when it reaches the next instruction -- then it will autoload a new list. Having a big list will reduce the number of autoloads, and allows you to see more. The list can contain up to 2048 lines. However, if you load more than 1000 lines, you are more likely to see performance problems.

There are two kinds of emulated memory in Bochs: Linear and Physical. Emulated Linear memory is mapped onto Physical memory by x86 virtual memory methods (paging and segmentation). If paging and segmenataion are "off", or "identity mapped", then both "types" of memory mean the same thing. But they still work a little differently. With the Internal Debugger, you can set breakpoints to either kind of memory, separately. Normally, you would use the "b" command to set breakpoints in physical mem, and "lb" to set breakpoints in linear mem. This frontend ONLY displays linear breakpoints. It does not bother trying to figure out the linear->physical reverse mapping to show physical breakpoints. (There are also "virtual" breakpoints that are also not shown.) All the types of breakpoints still WORK, it is just that you will not see them marked on the screen.

It will be obvious to you that the current instruction is marked in green, unless it is on a breakpoint, when it turns blue. Breakpoints are red, of course.

You must click a line in the window, before you can use frontend commands to set or clear a linear breakpoint on it. You can doubleclick (which saves steps) to set or clear a linear breakpoint.

#### The MemDump window

As of this version, the MemDump window isn't much more than a display of the contents of memory. In later versions, hopefully it will be expanded into a fairly fully-featured hexeditor. You can dump either physical mem, or linear mem. There are breakpoint-like things (that work with physical memory only, currently), called "watchpoints". A physical memory address can cause a break in the simulation if it is read, or written.

The frontend again does NOT try to calculate out the linear -> physical mapping in any attempt to display the physical watchpoints while viewing linear mem.

You must click a hex byte (on a physical mem dump that shows bytes), in order to set or clear a read and/or write watchpoint on that byte. Read watchpoints are green (on black), write watchpoints are red, watchpoints that are both write and read are blue. There is a hardcoded limit in Bochs of 16 of each type of watchpoint.

The MemDump window loads/shows 4K of memory at a time.

- PageUp/Down scrolls the display up or down through mem, 2K at a time

- Doubleclicking a line of memory allows you to change the byte values (Works on both linear and physical mem dumps)

- Doubleclicking with the Shift key down sets write watchpoints

- Doubleclicking with Alt sets read watchpoints

- You need to click once on the memory window before you can use its "Find" function. The Find function is pretty limited in scope, currently. It can only find bytes (or strings of bytes) within each 16byte "line"

#### The output window

The Output window shows anything that the Bochs Internal Debugger tries to send to you. The window is scrollable, but only keeps a limited history of output (10K). The ID is always spamming you with "Next at t=" and disassembly lines, that would tend to fill up the Output window with garbage -- so there are options to ignore either of these types of output.

#### The input window

The Input window is for sending user commands directly into the Bochs Internal Debugger -- bypassing the frontend. Results will appear in the Output Window. The Input window has a history feature for commands, using the Up and Down arrows -- it remembers 64 commands, 80 bytes each. No matter where you click on the frontend, you can always type directly into the Input box without clicking on it.

When the Input window is invisible, you should still be able to type into it -- after taking into account the bug listed at the bottom of this file.

Hitting Enter on a blank line will cause a Singlestep.

#### The param tree

The Bochs param_tree shows the internal state of most of Bochs. It will be expanded in the future to show even more. You can see the detailed state of all cpu registers -- including the "hidden" parts (look in the "bochs" branch). Or see the current state of most of the emulated hardware.

#### The stack window

The MemDump windows do not automatically refresh -- except for the Stack window. If you leave the stack window active, it will update as the stack changes. If you want to update the other MemDump windows with fresh data, hit Refresh.

#### The breakpoint/watchpoint window

Doubleclicking will delete a breakpoint or watchpoint.

#### The command button row

Just a (hopefully) convenient way of using the mouse, instead of the keyboard. If you don't like them, or they take up too much space, you can turn them off.

#### The CPU button row

This only shows up when you are running a multi-cpu simulation. Click on the CPU that you want to view. All CPUs are always stepped together, and they all stop the first time one hits some sort of breakpoint.

#### Docking / Resizing

If you grab one of the two vertical "bars" between the lists, you can horizontally resize the lists. The cursor will change, but there will be no animation.

If you grab the middle of one of the lists, and drag it on top of one of the other lists, you can reorder the positions of the lists on the screen. The cursor will change, but there will be no animation. You can set an alternate "docking order" at compile time, also, if you have a permanent preference. (See the top of the wenhdbg_h.h file, for compile-time customization.)

#### Additional Notes

If you have a really big GDT or Paging display in the MemDump window, and you select a different display, it may take several seconds to delete the big display before it can switch.

Uppercase text tends to seem a little annoying, but it really is a lot easier to read, especially on a proportional font. If you change to a fixed font, then you may want to switch the display to lowercase.

Most of the GUI debugger settings are now saved to an INI file on exit and restored at the next run.

## Tips and Techniques

### Specify log options by device

This table shows the name used for setting up the log actions per device, the prefix that appears in the log file or when a panic occurs and a short description of the module. This example shows how to turn on debug messages for a specific device in bochsrc.

    debug: action=ignore, pci=report

The names can be used in upper case or lower case, since the check is not case sensitive. Note that the module names cannot be checked while reading the config file, since most of the modules do not exist at this point. Invalid names or names of modules not present in the current configuration will cause a panic when the simulation is starting.

### Log function module names and prefixes

Name | Prefix | Description
ACPI | ACPI | PIIX4 ACPI controller
apic0 | APIC0 | APIC of first CPU
BIOS | BIOS | System BIOS
busmouse | BUSM | Busmouse
BXVGA | BXVGA | VGA adapter with VBE support
CD1 | CD1 | Lowlevel CD-ROM support for the first device (if configured, there can be CD2, CD3, CD4, ...)
cirrus | CIRRUS | Cirrus SVGA
CMOS | CMOS | CMOS RAM + RTC
cpu0 | CPU0 | First CPU (SMP emulation can have cpu1, cpu2, cpu3,...)
devices | DEV | Devices subsystem
DMA | DMA | DMA controller
E1000 | E1000 | Intel(R) Gigabit Ethernet
es1370 | ES1370 | ES1370 soundcard
extfpuirq | EXFIRQ | External FPU IRQ
floppy | FLOPPY | Floppy controller
gameport | GAME | Standard PC gameport
GDBST | GDBST | GDB stub support
GUI | GUI | Generic GUI code
harddrv | HD | IDE HD/CD emulation
hdimage | IMG | Disk image support
ioapic | IOAPIC | I/O APIC
iodebug | IODBG | I/O interface to debugger
keyboard | KBD | PS/2 keyboard and mouse
keymap | KEYMAP | Keyboard mapping
logio | IO | Bochs logging subsystem
memory | MEM0 | Memory management
MACGUI | MGUI | MacOS9 / MacOSX GUI
NE2K | NE2K | NE2000 ethernet adapter
NOGUI | NOGUI | GUI without input/output interface ("nogui")
parallel | PAR | Parallel port support
PCI | PCI | i440FX PCI bridge
pci2isa | P2ISA | PCI-to-ISA bridge
pcidev | PCIDEV | Host PCI device mapping
pcipnic | PNIC | PCI pseudo NIC
pci_ide | PIDE | PCI IDE controller
pc_system | SYS | CPU-to-devices interface and timing control
PIC | PIC | Programmable interrupt controller
PIT | PIT | I/O interface for 82C54 timer
pit82c54 | PIT81 | 82C54 timer core
PLUGIN | PLUGIN | Plugin interface
RFB | RFB | RFB GUI
SB16 | SB16 | SB16 soundcard
SCSICD | SCSICD | SCSI CD-ROM emulation for USB
SCSIHD | SCSIHD | SCSI hard drive emulation for USB
SDL | SDL | SDL 1.2.x GUI
SDL2 | SDL2 | SDL 2.x GUI
serial | SER | Serial port emulation
serial_raw | SERR | Lowlevel serial port support
siminterface | SIM | Simulator interface
slowdown_timer | STIMER | Slowdown timer
speaker | PCSPK | Lowlevel support for the PC speaker
TERM | TERM | Term GUI
unmappped | UNMAP | Unmapped I/O handler
usb_floppy | USBFDD | USB (UFI/CBI) floppy emulation
usb_ehci | EHCI | USB EHCI controller
usb_hid | USBHID | USB HID device emulation
usb_hub | USBHUB | External USB hub emulation
usb_msd | USBMSD | USB MSD (disk/CD-ROM) emulation
usb_ohci | OHCI | USB OHCI controller
usb_printer | USBPR | USB printer emulation
usb_uhci | UHCI | USB UHCI controller
usb_xhci | XHCI | USB xHCI controller
VGA | VGA | Standard VGA
vgabios | VBIOS | VGA BIOS
virt_timer | VTIMER | Virtual timer
WINGUI | WINGUI | WIN32 GUI
WX | WX | wxWidgets GUI
XGUI | XGUI | X11 GUI

### How to make a simple disk image

This was contributed by Greg Alexander in October 2001 and updated by Volker Ruppert in October 2013.

What you need:

- An executable version of Bochs. See Downloading Bochs and Compiling Bochs.

- The bximage program, included with Bochs.

- A FreeDOS boot disk, or a boot disk from another OS capable of producing DOS partitions (e.g. a Linux install disk).

- (Optional) mtools, a program for manipulating DOS disks/images.

#### Create a flat image

Option 1: Using the Unix `dd` utility:

You will need to know the geometry of the disk you want to create. You have to compute the disk sector count:

    Sectors = Cylinders * Heads * SectorsPerTrack

Use the dd command to create your file:

    dd if=/dev/zero of=teaching.img bs=512 count=sectors

(replace "sectors" with the number you computed at the previous step).

When you update your configuration file, please fill in the same cylinders, heads, and sector per track values.

Option 2: Run `bximage` to create a disk image file. You will be greeted with the following prompt:

    ========================================================================
                                    bximage
      Disk Image Creation / Conversion / Resize and Commit Tool for Bochs
             $ID: bximage.cc 11906 2013-10-23 08:35:21Z vruppert $
    ========================================================================

    1. Create new floppy or hard disk image
    2. Convert hard disk image to other format (mode)
    3. Resize hard disk image
    4. Commit 'undoable' redolog to base image

    0. Quit

    Please choose one [0]

Since we want to create a new image, we have to type '1' and then Enter.

    Do you want to create a floppy disk image or a hard disk image?
    Please type hd or fd. [hd]

Since we are creating a hard disk image, accept the default of hd by pressing Enter or typing 'hd' and pressing Enter. Next, bximage will ask for the type of hd to create:

    What kind of image should I create?
    Please type flat, sparse, growing or vpc. [flat]

We want to create a simple flat image, so accept the default by pressing Enter. Then, bximage will ask for the size of the disk image you want to create, in Megabytes:

    Enter the hard disk size in megabytes, between 1 and 8257535
    [10]

Enter the size of the hard disk you want to create, and press Enter. Then bximage will ask you for a filename to use for the file it is creating.

    What should be the name of the image?
    [c.img]

At this point, type in the filename you want to use for the image. The default of "c.img" is appropriate if this will be your only hard disk image. After you have typed in the name of the filename you want to use, press Enter. Bximage will tell you it is writing the disk and then it will show you a line that should be added to your `bochsrc` when you want to use this disk image. I named my 10 Megabyte image "teaching.img" and the output of bximage looked like this:

    [c.img] teaching.img

    Creating hard disk image 'c.img' with CHS=20/16/63

The following line should appear in your `bochsrc`:

      ata0-master: type=disk, path="teaching.img", mode=flat, cylinders=20, heads=16, spt=63

At this point, a file called "teaching.img" was created in my current directory and is ready to be used as an image file for a Bochs session.

You may want to name your image `teaching_20-16-63.img` so that you always know the values to use for CHS.

#### Partition and format your image file

Option 1: Using FreeDOS (Advantage: Creates a MBR on the partition.)

First, you need to edit the `bochsrc` file that Bochs uses for configuration information (see search-order). Open `bochsrc` with a text editor. Remove all lines in the file which start with "ata0-master:". Add the "ata0-master:" line that was displayed when you ran bximage to `bochsrc` at the same place where you removed the old "ata0-master:" lines from.

Also, you need to download or create a FreeDOS (or DOS, or Windows, or Linux) disk image. Modify the "floppya:" line in your `bochsrc` to point at the downloaded FreeDOS floppy image and change its status to "status=inserted".

Save and close your `bochsrc`. Now run Bochs (see using-bochs).

Use the standard FreeDOS commands `fdisk` and `format` to format your hard drive image. You must make the image bootable to be able to boot without a floppy disk. However, creating a bootable disk image is best done with a boot disk from the OS you intend to install on the image.

Option 2: Using mtools (Disadvantage: Cannot create bootable images without a MBR image.)

Use a text editor to add the following line to the file `~/.mtoolsrc`:

    drive c: file="path/filename.img" partition=1

Save and close `.mtoolsrc`. Next, execute the following commands to create a partition table for the drive image:

    mpartition -I -s spt -t cyl -h heads c:
    mpartition -cpv -s spt -t cyl -h heads c:

For example, for my 10 meg drive, I used:

    mpartition -I -s 63 -t 20 -h 16 c:
    mpartition -cpv -s 63 -t 20 -h 16 c:

Next, format the partition you just created using the mformat command:

    mformat c:

And you now have a formatted disk image containing a single DOS partition.

The mpartition command doesn't handle images larger than 1024 cylinders properly. The partition size reported by fdisk is okay, but mformat reports only 504 MB (tested with mtools 3.9.9).

### Use mtools to manipulate disk images

Mtools is a set of programs that can read, write, and format DOS disk images. There are links to the Mtools main page and a Win32 port of Mtools on the Bochs Links page, under Resources.

The mtools web site has a detailed manual. If anyone wants to write instructions specific to Bochs, we can add it right here.

### Bochs GNU/Linux DiskTools

Bochs-Tools are a collection of scripts and programs to be used together with Bochs developed by Bernhard Bablok. Main goal was to provide a more Unix-like interface to the emulator and to enable access to Bochs disk-images from outside of Bochs. The latest version is available at www.bablokb.de/bochs-tools.

### Win32 only: Tools to manipulate disk images

#### Winimage

Someone on the &devlist; mentioned that they use a program called WinImage, from www.winimage.com to read and write disk images (floppy and hard disk). Winimage is a commercial product with a 30-day trial.

If anyone wants to write a tutorial, send mail to &devlist; and volunteer.

#### DiskExplorer

This section was contributed by Luca Cassioli and Stanislav Shwartsman

I eventually found what all of you were looking for for a long time: a freeware, graphical, win32 compatible HardDisk image editor! It can handle a large variety of formats, but the one you need is VMWARE 2.0 PLAIN DISK: you can import/export to/from Bochs images COMPLETE DIRECTORIES!

You can find it at http://hp.vector.co.jp/authors/VA013937/editdisk/index_e.html

#### Ben Lunt's 'Ultimate' for Bochs and Win32/64

Ben Lunt wrote a utility for Windows to manipulate flat disk images and their included file systems.

You can find it at https://www.fysnet.net/ultimate/index.htm

This is a Windows Dialog based utility, with source, and includes the following items:

- Partitioning: MBR, PMBR, eMBR, EFI GPT

- File Systems: FAT, FYSFS, LeanFS, Ext2/3/4, SimpleFS, ExFAT

- Inserting, extracting, and deleting files from said file systems. (some file system support is currently read-only)

- Checking the integrity of said file systems and other items.

### X Windows: Color allocation problems

One common problem in X windows is that the screen colors can be abnormal if other X programs have already allocated all the colors. If the colors don't look right, try quitting colorful applications such as Netscape, clearing any complex images in the background, etc. so that Bochs has a chance to allocate the colors it needs.

If Bochs continues to have problems, or you want Bochs to have perfect colors without having to quit any other application, you can try turning on the private_colormap option in the configuration file. Using a private colormap causes the Bochs window to have its own set of 256 colors to work with. When the cursor is over the Bochs display, Bochs will look correct and other parts of the screen may change to very strange colors. When the cursor goes to any other window, the other windows will look correct and Bochs will have strange colors. A better solution, if your hardware can support it, is to run your X server with 24-bit or 32-bit color.

### Screen saver turns on too quickly

One thing you may notice is that the screen saver turns on (screen goes blank) very quickly after you have stopped typing. The reason is that Bochs simulates everything as fast as it can. If the CPU is very busy (running instructions nonstop), simulated time goes by slowly. If the CPU is idle (just waiting for you to type, for example), simulated time speeds up dramatically. In any case, if the screen saver blanks out the screen, just press a key (try shift or control) to restore the screen.

There are two strategies to fix this problem. One is to increase the `ips` parameter of the cpu option in your configuration file. This will cause the simulation time to pass more slowly. The other strategy is to enable the experimental realtime PIT, which tries to keep Bochs in sync with real time. See the `bochsrc` option clock.

### Mounting a disk image using the loop device

This section describes how to access a floppy or hard disk image within Linux using the loop device. Why would you want to do this? Let's say you have made a small Linux disk image for Bochs, and you want to install some more software on it. You have already downloaded the software onto your real system, so now you want to transfer it to the Bochs disk image. A fast way to transfer the files is to mount the disk image using the loop device.

#### ...on Linux

This section was contributed by Volker Ruppert.

    Today I have made some tests with the loop device, because I want to exchange
    files with the Bochs disk images.  This is what I found out:

    1.  Using Floppy images is easy, because there is no partition table:

        losetup /dev/loop0 /usr/local/bochs/dlxlinux/floppya.img

        Now you can use the image like a real floppy:

        - format           : mkfs.minix /dev/loop0
        - filesystem check : fsck.minix /dev/loop0
        - mount            : mount /dev/loop0 -o loop /mnt/floppy

        Before you want to restart Bochs you must do this:

        losetup -d /dev/loop0

        Don't forget to umount before.

    2.  If you want access to a hard disk image, you have to calculate the size of
        the first cylinder. This value is the offset argument for losetup.

        offset = bytes per sector * sectors per cylinder

        The command for dlxlinux image looks like this:

        losetup /dev/loop0 /usr/local/bochs/dlxlinux/hd10meg.img -o 8704

        For images created by bximage you must use the value 32256.

    3.  The hard disk image access doesn't work if the image contains more than
        one partition.

    4.  I have made this test with Linux and I don't know how
        this could be done with other operating systems.

#### ...on FreeBSD

This section was contributed by Alexander Schuch.

The following example mounts a Windows 95 hard disk image called `Windows 95 B (2031-16-63)` into the FreeBSD file system. It is specific to FreeBSD 5.x; for hints on how to do the same task on FreeBSD 4.x, or for more information in general, check the proper section of the FreeBSD handbook: Network, Memory, and File-Backed File Systems. You can use the same procedure for mounting floppy disk images.

    # mdconfig -a -t vnode -f "Windows 95 B (2031-16-63)"
    md0

mdconfig returns the device, your file now is accessable from.

    # mount -t msdosfs /dev/md0s1 /mnt

If you already have other md devices configured, you need to substitute md0s1 with, for example, md6s1.

Once you are done working with the image, unmount the md device and detach it.

    # umount /mnt
    # mdconfig -d -u 0

And again, if there are other md devices configured, use the proper device number. In case you forgot the number, just ask `mdconfig`, like:

    # mdconfig -l
    md7
    # mdconfig -d -u 7

### Simulating a Symmetric Multiprocessor (SMP) Machine

Bochs can now simulate an SMP machine when you use `--enable-smp` in the configure command. SMP support was added by Bryce Denney, who was very interested in watching a multiprocessor operating system work at a low level. It should also be helpful to operating system developers who are writing SMP drivers, or just for users who want to test drive an SMP machine to see what it looks like.

Starting with Bochs 2.2.6 you can set up the number of processors in the `bochsrc`. See bochsopt-cpu how to set up the number of processors.

It is important to understand that configuring Bochs for 4 processors will NOT make your single-threaded applications run faster in general! On the contrary, it has to spend time simulating idle processors as well as the ones doing your task. The point is to simulate an SMP system, not to speed up a uniprocessor application.

What was required to make SMP work in Bochs?

- local APIC on each processor with timer

- one I/O APIC model

- implement RDTSC (read time stamp counter)

- a data structure called the Intel Multiprocessor Configuration must be present in BIOS memory space. An SMP-aware operating system probes BIOS memory to find the structure, which contains information about how many processors, their IDs, interrupt sources, etc. Starting with Bochs 2.2.5 these structures are dynamically created by Bochs.

- ACPI support is required to boot SMP system in most of modern operating systems. For example, WinXP 64 bit require ACPI support even for single processor configuration.

What needs to be done to improve SMP support?

- debugger support is still limited. For example, you can set breakpoints, but you can't specify which processor you want to set the breakpoint for.

- test on any possible SMP operating systems. Currently success reported for Knoppix 4.0.2, WinNT 4.0 and WinXP SMP.

- several parts of the APIC model which weren't needed before are not implemented yet.

- A number of people have suggested using threads to simulate each CPU in a different thread. Then on a real SMP machine, the threads can execute in parallel. This is a great idea, but it's not done at present.

### Setting Up Networking in DLX Linux

All Bochs binaries come with a working version of DLX Linux. This section describes how to configure networking in Bochs and enable it within DLX Linux. First you must add a `ne2k` line in your bochsrc file. Then, when you boot the DLX Linux image, you need to type some Linux commands to set up an IP address, a network route, and a name server.

When you have an `ne2k` line in your bochsrc file, Bochs will emulate a network card called an NE2000. Below are some examples of valid `ne2k` lines for various operating systems. Choose the one that's closest to what you need, add it to your bochsrc file, and edit the values if necessary.

      # sample for Mac OS X
      ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=en0
      # sample for FreeBSD
      ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=xl0
      # sample for Linux
      ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=linux, ethdev=eth0
      # sample for Windows
      ne2k: ioaddr=0x300, irq=9, mac=00:c4:3B:00:C3:00, ethmod=win32, ethdev=NE2000

You see the pattern. Usually, you won't need to change the I/O address, IRQ number, or MAC address. The `ethmod` value depends on your host operating system, and it must be either `null`, `fbsd` (for FreeBSD or OpenBSD), `linux`, or `win32`. The `ethdev` setting is the name of the network interface on your system, and is also OS-dependent. On UNIX systems you can get the name of the network interface by running `ifconfig`. (Don't choose the loopback interface.) On Windows systems, the correct ethdev setting is not always obvious, so we provide a utility called `niclist` to list the names of network interfaces to use. When you run `niclist`, it will suggest an `ne2k` line which is a very good first try.

Next, if you are on a UNIX machine you will need to become the root user. Since Bochs is sending and receiving raw network packets, you need to be root to use the network device. To allow normal users to do this would be a security problem.

Now run Bochs to boot DLX Linux. Press 'enter' a few times to accept the default configuration choices. This tells Bochs read the configuration file and then begin. DLX Linux should boot in the Bochs window, and you should see that Linux detects the NE2000 card. Eventually it gets to a login prompt.

      ne.c:v1.10 9/23/94 Donald Becker (becker@cesdis.gsfc.nasa.gov)
      NE*000 ethercard probe at 0x300: b0 c4 20 00 00 00
      eth0: NE2000 found at 0x300, using IRQ 9.

At the login prompt, type "root" to log in as root. Then type the ifconfig and route commands to set up networking. The exact IP numbers in the example won't work for you; you must choose an IP configuration that is legal on your network.

      dlx login: root
      Linux 1.3.89.
      dlx:~# ifconfig eth0 192.168.0.99         # set bochs IP address
      dlx:~# route add -net 192.168.0.0         # first 3 numbers match IP
      dlx:~# route add default gw 192.168.0.1   # your gateway to the net
      dlx:~# _

The Bochs IP address must be an unused IP address on your network. If you duplicate someone else's IP address, your network will become very confused.

Finally, the network is ready and you can test it out with ping, telnet, or ftp to various machines by their numerical IP address. Keep in mind that for all UNIX host platforms, Bochs networking cannot talk to the host machine. That means the host machine can't be the gateway either. You need another physical machine on the network that Bochs can talk to. On Win32 this restriction does not apply.

When you have a working network configuration, you can make DLX Linux recreate the same settings the next time you boot. Just add the ifconfig and route commands to the end of /etc/rc.d/rc.inet1. I won't try to describe how to use the `vi` editor in this limited amount of space...

To configure a name server, set up `/etc/resolv.conf` with the IP address of your name server as shown.

       dlx:~# echo 'nameserver 192.168.0.1' > /etc/resolv.conf

### Configuring and using a tuntap network interface

If you use linux (optionally FreeBSD and Solaris, not tested), you may want to access the network through a tuntap interface. The main advantage of this interface, is that the guest has access to the host. The guest can even have access to the whole network if the host routes or masquerades the guest requests. No extra IP address is needed, all can be done using private IP addresses.

You'll find here instructions to set up Linux/Bochs to provide network access to the guest OS through a tuntap interface and private IP network. We're going to see howto :

- enable the tuntap interface in the Linux Kernel

- configure Bochs to use the tuntap interface

- set up the private network between the host and the guest

- set up the host to masquerade the guest network accesses

#### Tuntap description

From the tuntap.txt file in the Linux kernel tree :

      TUN/TAP provides packet reception and transmission for user space programs.
      It can be viewed as a simple Point-to-Point or Ethernet device, which
      instead of receiving packets from a physical media, receives them from
      user space program and instead of sending packets via physical media
      writes them to the user space program.

      When a program opens /dev/net/tun, driver creates and registers corresponding
      net device tunX or tapX. After a program closed above devices, driver will
      automatically delete tunXX or tapXX device and all routes corresponding to it.

#### Set up the linux Kernel

much of the information of the following section is taken from this email from Samuel Rydh of the Mac-On-Linux list

First make sure the tuntap module is included in the kernel :

- if you use a recent distribution, chances are that the needed modules are already build

  Make sure that "Kernel module loader" - module auto-loading support is enabled in your kernel.

  Add following line to the /etc/modules.conf:

       alias char-major-10-200 tun

  Run:

       depmod -a

  The driver will be automatically loaded when application access /dev/net/tun.

- Otherwise, recompile the kernel, including the configuration option

       CONFIG_TUN (Network device support -> Universal TUN/TAP device driver support)

Make sure there is a /dev/net/tun device. (Can be created with '`mkdir /dev/net ; mknod /dev/net/tun c 10 200'`).

In the same way, to use masquerading, you need a kernel with the following options :

     CONFIG_IP_NF_CONNTRACK (Connection tracking)
     CONFIG_IP_NF_IPTABLES (IP tables support)
     CONFIG_IP_NF_NAT (Full NAT)

Some of the other options in this group is probably also needed, (but the default setting should be OK).

#### Configure Bochs to use the tuntap interface

Make sure Bochs has one of the network adapters enabled. If you have to recompile Bochs, use `--enable-ne2000` or `--enable-e1000` when running `./configure` (see compiling)

edit your `.bochsrc` configuration file and add something like :

      ne2k: ioaddr=0x300, irq=9, mac=fe:fd:00:00:00:01,
                              ethmod=tuntap, ethdev=/dev/net/tun0, script=/path/to/tunconfig

Since the tuntap interface cannot be configured until a process opens it, Bochs may run a script file for you. In this case `/path/to/tunconfig` should be changed to match the actual place where you'll create this script.

#### Set up the private network between the host and the guest

We'll set up a private network between the host and the guest with the following parameters:

                    Host IP : 192.168.1.1
                    Guest IP : 192.168.1.2

If your parameters are different, adapt the rest of the section to suit your needs.

Create the `/path/to/tunconfig` script :

            #!/bin/bash
            /sbin/ifconfig ${1##/*/} 192.168.1.1

The script gets the interface name as the first parameter. Linux will forward incoming packets between interfaces.

Make it executable :

    chmod 755 /path/to/tunconfig

Run Bochs, install the guest OS, and set the following network parameters in the guest OS:

            IP: 192.168.1.2
            netmask: 255.255.255.0
            gateway: 192.168.1.1
            nameserver: whatever is used in linux

Bochs must be started by root (at least for now - the script won't have root privileges otherwise).

You may also have to edit /etc/hosts.allow in the host OS and add :

            ALL: 192.168.1.2

Don't forget to set up the route on the guest.

At this point, you should be able to ping/telnet/ftp/ssh the guest from the host and vice-versa.

#### Set up the host to masquerade the guest network accesses

We are going to set up standard masquerading configuration. Edit the `/path/to/tunconfig` script ans add :

            /sbin/iptables -D POSTROUTING -t nat -s 192.168.1.0/24 -d ! 192.168.1.0/24 -j MASQUERADE >& /dev/null
            /sbin/iptables -t nat -s 192.168.1.0/24 -d ! 192.168.1.0/24 -A POSTROUTING -j MASQUERADE
            echo 1 > /proc/sys/net/ipv4/ip_forward

The configuration assumes the default policy is ACCEPT (can be examined by doing '`/sbin/iptables -L`')

The iptables package must be installed.

And voila... The host should forward the packets of the guest to the rest of your network. You could even have access to the internet...

You may need to load other modules if you want to use other fancy protocols (ftp,etc...)

### Using the 'slirp' networking module

Slirp is a software program that emulates a PPP, SLIP, or CSLIP connection to the Internet via a shell account. The original version has been written by Danny Gasparovski in 1995. It has been integrated in QEMU to provide user mode networking. Now a port of the QEMU Slirp implementation is available in Bochs.

Features and limitations:

- Access to the internet and host network services without root/Administrator privileges or additional libraries.

- Builtin DHCP and TFTP servers

- Optional SMB support on Linux

- ICMP traffic (ping) from guest to the host's network or the internet not supported

- guest access from the host or external network disabled by default

This example shows how to use the 'slirp' module with the NE2000 adapter. The line is very similar for the E1000 or PCI Pseudo NIC.

    ne2k: mac=52:54:00:12:34:56, ethmod=slirp, ethdev=/home/volker/tests/bochs, script=""

The "ethdev" value specifies the TFTP root directory. All other options for Slirp must be set in a config file specified with "script" parameter. If no config file is set up, Bochs uses this "classic" Slirp configuration shown in the "Default" column below.

#### Advanced Slirp setup with config file

An example for a Slirp config file can be found in the Bochs sources and in binary packages (`misc/slirp.conf`).

#### Slirp config file options

Option | Description | Default value
restricted | if set to 1, only built-in services are available | 0
net | base IP address of the virtual network | 10.0.2.0
mask | netmask of the virtual network | 255.255.255.0
host | IP address of the DHCP and TFTP server | 10.0.2.2
hostname | DHCP client hostname | undefined
dhcpstart | start address of DHCP pool | 10.0.2.15
dns | IP address of the virtual DNS server | 10.0.2.3
bootfile | boot filename returned by DHCP | undefined
dnssearch | comma-separated list of DNS suffixes to search (DHCP extension) | undefined
smb_export | absolute path to the shared folder (non-Windows SMB support) | undefined
smb_srv | alternative IP address of the SMB server | 10.0.2.4
hostfwd | map guest port to host port for host-to-guest access (see below for details) | undefined
pktlog | specify log file to enable packet logging in text format | disabled

#### Access to guest services from the host

With the config file option "hostfwd" you can map guest ports to ports on the host system. This is the format of the directive:

      hostfwd = protocol:hostaddr:hostport-guestaddr:guestport

The host and guest IP addresses are optional. This example shows how to access the guest SSH server using the host port 12345.

      hostfwd = tcp::12345-:22

Up to 5 port redirection rules are supported per slirp instance.

### Using the 'socket' networking module

The original patch for the 'socket' networking module has been written by Mariusz Matuszek in 2003. It supported interconnecting two Bochs sessions running on the same machine via UDP using an external program called 'bxhub'.

The 'socket' networking module is now integrated in the Bochs code with these extensions:

- Integrated 'vnet' server features (ARP, ICMP-echo, DHCP, DNS, FTP and TFTP)

- Limited DNS server for 'vnet' and connected clients

- Command line options for 'bxhub' added for base UDP port and 'vnet' server features

- Support for connects from up to 6 Bochs sessions

- Support for connecting 'bxhub' on other machine

The 'socket' networking module uses two UDP ports per Bochs session. By default, the first session receives packets from port 40000 and sends packets to port 40001. The second session uses then the ports 40002 and 40003. For further sessions the port numbers are incremented accordingly. The port number for receiving packets is specified with the 'ethdev' parameter of the bochsrc line for the network adapter. The format is host:port for connecting the 'bxhub' utility. If it runs on the same machine ('localhost') the host name can be omitted.

These examples show how to use the 'socket' module with the NE2000 adapter. The line is very similar for the E1000 or PCI Pseudo NIC.

    ne2k: mac=52:54:00:12:34:56, ethmod=socket, ethdev=mymachine:40000, script=""
    ne2k: mac=52:54:00:12:34:56, ethmod=socket, ethdev=40000, script=""

#### Using the 'bxhub' utility

If `bxhub` is started without command line options, these default values are used:

- UDP base port 40000

- 2 client connections

- Server MAC address b0:c4:20:00:00:0f

- FTP / TFTP support disabled

To change the default settings, these parameters are supported:

    Usage: bxhub [options]

    Supported options:
      -ports=...    number of virtual ethernet ports (2 - 6)
      -base=...     base UDP port (bxhub uses 2 ports per Bochs session)
      -mac=...      host MAC address (default is b0:c4:20:00:00:0f)
      -tftp=...     enable FTP and TFTP support using specified directory as root
      -bootfile=... network bootfile reported by DHCP - located on TFTP server
      -loglev=...   set log level (0 - 3, default 1)
      -logfile=...  send log output to file
      --help        display this help and exit

#### The vnet FTP service

The 'vnet' server now provides passive FTP support also using the TFTP directory as root. The FTP server name is vnet-ftp. For read only access, the username must be set to anonymous with any password. This mode supports browsing the directory subtree and downloading files. For read/write access, the user must be set to bochs with password bochs. This enables support for uploading, renaming and deleting files, creating, and removing directories.

### Using Bochs and the remote GDB stub

This section covers how you can use Bochs with a remote GDB stub to debug your kernel.

#### Configuring Bochs

The GDB stub is not active in standard Bochs binary package. So you must recompile Bochs. Download the Bochs source package, unpack it and run the configure script with the `--enable-gdb-stub` argument.

      $ ./configure --enable-gdb-stub

After that, just run make and you should have a Bochs binary that contain a GDB stub in your directory.

#### Running Bochs

Enable the gdbstub option in `bochsrc`, then just start Bochs as normal. Bochs will stop and wait for GDB to connect to the stub.

#### Running GDB

Bochs GDB stub waits for a connection on TCP port 1234. Just start GDB like this:

      $ gdb YOUR-KERNEL
      .
      .
      .
      (gdb) target remote localhost:1234
      Remote debugging using localhost:1234
      0x0000fff0 in ?? ()
      (gdb)

You are now connected to the remote GDB stub in Bochs. You are now able to set breakpoints. Use the continue (c) command to continue the simulation. Hitting ^C works. Example:

      Program received signal 0, Signal 0.
      syscall_testsuite_result (aux=0x1f11fe4) at ../rtmk/syscalls.c:33
      33     {
      (gdb)

### Using the serial port

This section describes what is possible to do with Bochs serial port emulation. These examples use dlxlinux disk image (downloaded from http://bochs.sourceforge.net/guestos/dlxlinux3.tar.gz ) running as guest, on a debian x86 linux 2.4.19 host.

For the examples to work in dlxlinux, after you login as root, you will need to kill the running gpm, as it grabs the serial port.

    Welcome to DLX V1.0 (C) 1995-96 Erich Boehm
                        (C) 1995    Hannes Boehm

    dlx login: root
    Linux 1.3.89.
    dlx:~# ps | grep gpm
       30  S0 S     0:00 /usr/bin/gpm -t bare
       40   1 S     0:00 grep gpm
    dlx:~# kill -9 30
    dlx:~#

#### Logging serial port output to a file

The first example shows how to log information sent to the serial port on the guest system into a file on the host system.

Update the com1: section of your configuration file:

    com1: enabled=1, mode=file, dev=serial.txt

After you've launch dlxlinux, everything sent to the serial port will be logged to serial.txt :

    dlx:~# echo "logging to the serial port" > /dev/cua0

    host$ cat serial.txt
    logging to the serial port
    host$

#### Interactivity : connecting to a virtual terminal

The second example shows how to connect to the guest OS, using a virtual terminal on the host OS.

First, you need to find an unused virtual terminal. Typically, X uses vt7; vt8 and up are unused. On my system, I can switch from X to vt9 by pressing ctrl-alt-f9 : this virtual terminal is not used, the screen is all black. Pressing alt-f7 switches back to X.

Once you found an unused vt, update the com1: section of your configuration file:

    com1: enabled=1, mode=term, dev=/dev/tty9

The number must be set according to the terminal you want to use (here 9).

Now, launch dlxlinux. After you log in as root and kill gpm, enter the following command:

    dlx:~# /sbin/agetty 38400 cua0

If you switch to vt9, you can see dlx welcome banner, and the login prompt:

    Welcome to DLX V1.0 (C) 1995-96 Erich Boehm
                        (C) 1995    Hannes Boehm

    dlx login:

Note that dlxlinux is configured so you can not login as root from a serial port. If you want to login, you have to create a new user first.

Also, if you plan to use this feature, the best would be to deactivate gpm in /etc/rc.d/rc.local, and add a agetty line in /etc/inittab, for example:

    T0:1234:respawn:/bin/agetty 38400 cua0

#### Interactivity : connecting to a pseudo terminal

The third example is very similar to the second one, except that we connect to the guest OS with kermit as client, and we the connection is done through a pseudo terminal.

This example uses /dev/ptyp0 and /dev/ttyp0 as pseudo terminal pair. We will tie Bochs to the controlling terminal, whereas kermit will use the slave terminal.

Update the com1: section of your configuration file:

    com1: enabled=1, mode=term, dev=/dev/ptyp0

and launch dlxlinux. After you log in as root, enter the command:

    dlx:~# /sbin/agetty 38400 cua0

Then in the host OS, launch kermit :

    host$ kermit -l /dev/ttyp0
    C-Kermit 7.0.196, 1 Jan 2000, for Linux
     Copyright (C) 1985, 2000,
      Trustees of Columbia University in the City of New York.
    Type ? or HELP for help.
    (/tmp/) C-Kermit>connect
    Connecting to /dev/ttyp0, speed 0.
    The escape character is Ctrl-\ (ASCII 28, FS)
    Type the escape character followed by C to get back,
    or followed by ? to see other options.
    ----------------------------------------------------

    Welcome to DLX V1.0 (C) 1995-96 Erich Boehm
                        (C) 1995    Hannes Boehm

    dlx login:

The same comments as for example 2 apply here.

### BIOS Tips

#### Booting from CD-ROMs

A bootable CD-ROM has a special layout that is detected by the BIOS boot loader code, and executed if it conforms the specifications. This layout is called "El Torito Bootable CD-ROM Format Specification" and has been published by Phoenix and IBM. A copy of this spec is on Bochs tech specs page.

El Torito specifies 3 ways to have a bootable CD:

- floppy emulation boot: A standard floppy image is burnt on the CD. In this case the BIOS has to redirect all first floppy accesses to this image and the real floppy drive becomes the second one.

- a "no emulation" boot: In this case the BIOS is instructed to load an arbitrary number of sectors straight into memory, and execute it.

- hard disk emulation: A hard disk image is burnt on the CD. The BIOS has to redirect all hard disk accesses to that image. The real hard disks are still available, with BIOS numbers 81h and up.

In Bochs 2.0, hard disk emulation is not implemented in the BIOS. There are also subtilities about multiple boot-images CD-ROMs, that are not handled by Bochs.

However, our BIOS may be more strict than real PC BIOSes, I don't know. But I would definitely be interested to know of any CD that can boot on real hardware, but does not in Bochs.

When failing to boot from CD-ROM, the BIOS outputs the reason of the failure as an error code, in the log file, and on the screen.

Here is a summary of what can happen when booting from the CD.

#### CD Boot error codes

Error code | Reason
0x01 | no atapi device found
0x02 | no atapi CD-ROM found
0x03 | cannot read cd - BRVD
0x04 | cd is not eltorito (BRVD)
0x05 | cd is not eltorito (ISO TAG)
0x06 | cd is not eltorito (ELTORITO TAG)
0x07 | cannot read cd - boot catalog
0x08 | boot catalog : bad header
0x09 | boot catalog : bad platform
0x0A | boot catalog : bad signature
0x0B | boot catalog : bootable flag not set
0x0C | cannot read cd - boot image

    0x01 no atapi device found
    0x02 no atapi CD-ROM found

For the first two errors, an ata-*: type=cdrom is probably missing from the configuration file. This is what you get if no CD-ROM has been defined in Bochs conf file.

    0x03 cannot read cd - BRVD

For this error, the CD-ROM support has not been compiled in Bochs, or Bochs could not open the file or device. This is what you get if Bochs is not able to read the cd.

    0x04 cd is not eltorito (BRVD)
    0x05 cd is not eltorito (ISO TAG)
    0x06 cd is not eltorito (ELTORITO TAG)

For these errors, the data has been read from the cd, but the cd does not conform to the El Torito specification. This is what you get if the cd is not bootable.

    0x08 boot catalog : bad header
    0x09 boot catalog : bad platform
    0x0A boot catalog : bad signature
    0x0B boot catalog : bootable flag not set

now the cd is eltorito, but the boot catalog is corrupted, or the cd was made to boot on a ppc system. This should not happen for a x86 bootable cd.

    0x07 cannot read cd - boot catalog
    0x0C cannot read cd - boot image

here, specific part of the cd could not be read. This should definitely not happen.

#### Disk translation

Since the beginning of the PC era, disks have grown in size by a factor of 10000. Due to differences between the ATA specification and BIOSes implementations, when disks reached critical sizes, it became necessary to translate the CHS geometry (cylinders, heads, sectors per track) between the BIOS (int 13h) and the ATA interface. Please refer to the ATA-FAQ and Hale Landis' document for a complete discussion of the problem.

Unfortunately, there has never been any standard on the translation algorithms.

Bochs implements 4 well-known algorithms, selectable in the configuration file in the "`ataX-xxxx: ..., translation='algorithm'`" section.

#### Disk translation algorithms

Algorithm | Maximum disk size | Maximum logical and physical geometry (CHS) | Description
none | 528MB (1032192 sectors) | LCHS:1024/16/63 PCHS:1024/16/63 | no translation is done. The CHS received at the int13h interface is sent as is to the ATA interface.
large | 4.2GB (8257536 sectors) | LCHS:1024/128/63 PCHS:8192/16/63 | a standard bitshift algorithm (named Extended-CHS) is used to translate the CHS between the int13h interface and the ATA interface. The translation is achieved by multiplying/dividing the cylinder/head count by a power of 2 (2, 4 or 8). (a factor of 16 could not be used because the head count would become 256, and MS-DOS thought this was 0) Note that the number of sectors per track is not changed, so a lower spt value will lead to a lower maximum disk size.
echs |  |  | synonym for large
rechs | 7.9GB (15482880 sectors) | LCHS:1024/240/63 PCHS:15360/16/63 | a revised bitshift algorithm (called Revised Extended-CHS) is used to translate the CHS between the int13h interface and the ATA interface. First the number of physical heads is forced to 15, and the number of cylinders is adjusted accordingly. Then, as in the simple extended CHS algorithm, the translation is achieved by multiplying/dividing the cylinder/head count by a power of 2 (2, 4, 8 or 16). The head count being forced to 15, it can safely be multiplied by 16 without crashing dos. Note that the number of sectors per track is not changed, so a lower spt value will lead to a lower maximum disk size.
lba | 8.4GB (16450560 sectors) | LCHS:1024/255/63 PCHS:16320/16/63 | An LBA-assisted algorithm is used to translate the CHS between the int13h interface and the ATA interface. The translation is achieved by first computing the physical size of the disk (LBA=C*H*S). Then the sectors per track is forced to 63, and the head count to 255. Then the cylinder count is computed (C=LBA/(63*255)) Note that the number of sectors per track is forced to 63 in the logical geometry, regardless of the actual geometry reported by the disk. Also note that the LBA-assisted algorithm has nothing to do with LBA access at the ATA interface.
auto |  |  | the best suited algorithm between none, large and lba is used

Setting a specific CHS translation should be done if you use a disk dump of an actual disk, or use a real disk as a block device. You need to know which geometry was used to format the disk, and which translation was used. You must not set the translation to 'auto'.

rechs translation should only be useful for Compaq users who wants to use a disk as a block device. Please report if you know any other system that uses such translation.

If you plan to create a new disk image (for example with bximage), format it and install an OS on it, select the "auto" translation for an automatic selection of the best algorithm based on the disk image size. Be warned that an image created with the "auto" translation might not be readable with previous versions of Bochs. Upward compatibility will be maintained.

This translation applies only to int13h BIOS disk accesses. Older OSes (e.g., MS-DOS) tend to use them a lot. On modern OSes, disk accesses through BIOS int13h are limited to boot loaders. The usual rules and tricks of the installed OS still apply (i.e., 1024 cylinders boot limit).

### How to enter special key combination

Your window manager may trap the key combination you want to enter in Bochs guest OS, for example control alt delete. Here is a work-around:

Press and hold control alt, move your mouse cursor outside of the Bochs window. Release them, move the cursor back in the Bochs window and press delete.

This should work for any key combination.

If you need one key combination frequently, set it up as user key combination with the keyboard option in your configuration file. This key combination is sent to the guest OS when you press the user button in the headerbar. Depending on the used display_library option, it may even be possible to edit the shortcut before sending it.

### Notes about VESA usage

Since Bochs 1.4 it is possible to use VESA graphics. There are some limitations in the current implementation, but in general it should work ok (we have run several test programs, the XFree86 VESA display driver, etc.)

In order to use VESA VBE, you need to enable it in your `bochsrc` by setting the vga option to `vbe`. Finally, you need to use the LGPL'd VGABIOS as vgaromimage option for applications to correctly detect VESA support.

The VGABIOS is already included in the Bochs release, so no separate download is necessary.

To take advantage of the VBE, you must tell Bochs to use the LGPL'd VGA BIOS version 0.4c or higher. A current version of the VGA BIOS will work.

Current limitations:

- 4bpp modes support is incomplete (8, 15, 16, 24 and 32bpp should work)

- banked mode is very slow (if you can, just use Linear Frame Buffering instead!)

- only 320x200, 640x400, 640x480, 800x600, 1024x768 are currently supported

Interesting Facts:

- You need a display driver capable of using the VESA BIOS for this to work (a recent XFree86 will do, Windows 9x/NT/2K/XP probably will not work 'out of the box'.

- Currently the VBE2 extension should be supported ok

#### Instructions to setup Bochs VBE in Windows Guest OS

This was contributed by Martin Bochnig in February 2004.

    Instructions for Win95/98:
    ==========================
    I can only confirm that SciTech finally made a VBE driver
    for Windows. It works out of the box, at least with win95
    as guest OS, provided you use Bochs 2.1 with the LGPL
    vgabios.

    Here is how I did it :
    - install win95 with the vga driver.
    - download sdd 7 beta from
    - download pmhelp.vxd from
    - copy pmhelp.vxd to the win95 system directory
    - install sdd7

    800x600 and 1024x768 in 16 and 24 bpp modes here.
    I did not try 32bpp.

This was contributed by Stanislav Shwartsman in September 2004.

    Instructions for Win2000/XP:
    ============================

    Bochs VBE Display Drivers for Windows NT/2000

### Notes about Cirrus SVGA usage

Since Bochs 2.2 it is possible to use Cirrus SVGA graphics. The Cirrus device supports both ISA and PCI depending on the `bochsrc` settings. If PCI is disabled or the Cirrus card is not assigned to a PCI slot, it appears as a CL-GD5430 ISA with 2MB VRAM. If you assign the Cirrus card to a PCI slot, it appears as a CL-GD5446 PCI with 4MB VRAM.

In order to use Cirrus SVGA, you need to compile Bochs using the `--enable-clgd54xx` option and enable it in your `bochsrc` by setting the vga option to `cirrus`. Finally, you need to use the Cirrus version of the LGPL'd VGABIOS as vgaromimage option for applications to correctly detect Cirrus support.

      # Enable CL-GD5446 PCI
      vga: extension=cirrus
      vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest-cirrus
      pci: enabled=1, chipset=i440fx, slot1=cirrus

The VGABIOS is already included in the Bochs release, so no separate download is necessary.

### Notes about Voodoo Graphics usage

Bochs supports the emulation of 4 different 3dfx Voodoo Graphics adapter models. The Voodoo1 and Voodoo2 models are 3D-only add-on cards and require a VGA compatible primary device. The Voodoo Banshee and its successor Voodoo3 have both a VGA core and a 2D/3D core, so no other VGA card is required. The 2D/3D cards can be assigned to AGP if the i440BX chipset is selected (slot #5).

To emulate the Voodoo1 or Voodoo2 device only the "model" parameter of the bochsrc option "voodoo" needs to be set. If the vga extension option is set to "voodoo" in that case, the primary display adapter is an ISA VGA card.

For emulating the Voodoo Banshee or Voodoo3 adapter, the vga extension option must be set to "voodoo". Using a different primary display adapter and a Banshee compatible device with its VGA interface disabled is not implemented yet. For both Banshee and Voodoo3 there is now a specific version of the LGPL'd VGABIOS with Voodoo Banshee specific code called `VGABIOS-lgpl-latest-banshee`. The binary file is compiled for the Banshee PCI model, but Bochs modifies the VGABIOS data after loading to support the Voodoo3 and AGP models properly.

These bochsrc settings should be used for Voodoo Banshee PCI:

      vga: extension=voodoo
      vgaromimage: file=VGABIOS-lgpl-latest-banshee
      voodoo: model=banshee

This additional setting is required for Voodoo Banshee AGP:

      pci: chipset=i440bx, slot5=voodoo

To support the Voodoo3 just change the model:

      voodoo: model=voodoo3

### Disk Image Modes

Bochs can handle independent disk image format for each disk present on the ata interfaces. The disk image type is selected in the configuration file by the "mode" option of the ataX-xxx directives. Example:

    ata0-master: type=disk, mode=flat, path=10M.sample, cylinders=306, heads=4, spt=17

If unspecified, the default "mode" is flat.

### Supported Disk Modes

Name | Description | Features
flat | one file, flat layout | accessible with mtools or winimage-like tools
concat | multiple files, concatenated | mappable to contained partitions
dll | accessed through a DLL | developer specific, win32 / win64 only
sparse | up to 10 layers stackable files | commitable, rollbackable, growing
vmware3 | vmware3 disk support | vmware version 3 compatibility
vmware4 | vmware4 disk support | vmware version 4 (VMDK) compatibility
undoable | read-only base file with a commitable redolog | commitable, rollbackable
growing | one growing file | growing
volatile | read-only base file with a volatile redolog | always rollbacked
vpc | VirtualPC disk support | fixed / dynamic size supported
vbox | Oracle(tm) VM VirtualBox disk support | VDI version 1.1 fixed / dynamic size supported
vvfat | local directory appears as VFAT disk (with volatile redolog) | optional commit or rollback

#### flat

##### description

In flat mode, all sectors of the harddisk are stored in one flat file, in lba order.

##### image creation

Flat disk images can be created with the bximage utility (see using-bximage for more information).

##### path

The "path" option of the ataX-xxx directive in the configuration file must point to the flat image file.

##### external tools

Flat images content can be accessed from the host by the following tools :

- mtools (see mtools)

- mount with a loopback (see loop-device-usage)

- Winimage / DiskExplorer (see winimage)

- Bochs Tools (see bochs-linux-disktools)

##### typical use

Flat mode is Bochs default harddisk layout. This is also the layout of disk images provided on Bochs websites.

##### limitations

On some host OSes, Bochs flat disk images are limited to 2GiB.

#### concat

##### description

In concat mode, all sectors of the harddisk are stored in several flat files, in lba order.

##### image creation

Disk images for the usage in 'concat' mode can be created as 'flat' mode image files with the bximage utility (see using-bximage for more information).

##### path

The "path" option of the ataX-xxx directive in the configuration file must point to the first file (e.g. win95-1). The lower layer files names are found by adding 1 to the last character (e.g. win95-2, win95-3, etc.).

##### external tools

If every single file contains a complete partition, they can be accessed with same tools as the 'flat' mode images.

##### typical use

If the partition sizes and file sizes are set up correctly, this allows you to store each partition in a separate file, which is very convenient if you want to operate on a single partition (e.g. mount with loopback, create file system, fsck, etc.).

##### limitations

On some host OSes, there is a limit of 2GiB per file.

#### dll

##### description

This mode is only useful for developers and needs an additional win32 / win64 DLL loaded by Bochs at runtime.

#### sparse

##### description

Sparse disk support has been added by JustinSB. Sparse disk features are:

- Large hard drive can be created, and only used space will be stored in the file. In practice, on Unix, this is not a large gain as it is done anyway.

- Multiple sparse drive images can be mounted on top of each other. Writes go to the top image. This allows several similar configurations to share a master "base" file, and also allows file system rollback or no-write options. Up to 10 disk images can be layered on top of each other.

##### image creation

Sparse disk images must be created with the bximage utility (see using-bximage for more information). Be sure to enter "sparse" when selecting the image type.

##### path

The "path" option of the ataX-xxx directive in the configuration file must point to the top layered file. The lower layer files names are found by substracting 1 from the last character (must be a digit)

##### external tools

The bximage utility (see using-bximage provides convert and resize support for "sparse" mode images.

##### typical use

###### Space Saving

Create a sparse disk image using bximage. Set size to eg 10GB. Only allocated space will be stored, so your drive image should be only about as large as the files stored on it.

###### Disk Rollback

- Create a sparse disk image called "c.img.0". Point .bochsrc at "c.img.0". In Bochs, install your favorite OS. Switch off Bochs.

- Create a sparse disk image (of the same size) and name it "c.img.1". Point .bochsrc at "c.img.1" "c.img.0" is visible, but all writes go to "c.img.1". After using Bochs, you can simply delete "c.img.1" to undo changes and go back to a clean OS install.

###### Disk Optional Commit

- Create a sparse disk image called "c.img.0". Point .bochsrc at "c.img.0". In Bochs, install your favorite OS. Switch off Bochs.

- Create a sparse disk image (of the same size) and name it "c.img.1". Point .bochsrc at "c.img.1" "c.img.0" is visible, but all writes go to "c.img.1". After using Bochs, if you want to keep the changes, use the (currently non-existent) merge utility to make a single unified drive image.

- Alternatively, simply create a new partition on top called "c.img.2".

###### Common Base

- Create a sparse disk image called "base.img". Point .bochsrc at "base.img". In Bochs, install your favorite OS. Switch off Bochs.

- Create a sparse disk image (of the same size) and name it "www.img.1". Make "wwww.img.0" a symlink to "base.img". Point .bochsrc at "www.img.1". Using Bochs, install a webserver.

- Create a symlink to "base.img" called "db.img.0". Create a sparse disk image (of the same size) and name it "db.img.1". Point .bochsrc at "db.img.1". Using Bochs, install a database server.

Now both a database server and webserver can be run in separate virtual machines, but they share the common OS image, saving drive space.

##### limitations

There is a need for supporting utilities (yet unwritten) :

- to merge two sparse disk images into a single image

- to defragment a sparse disk image and remove unused space

#### vmware3 / vmware4

##### description

Sharvil Nanavati has added vmware3/4 disk image support into Bochs for Net Integration Technologies, Inc. You should be able to use disk images created by vmware version 3 and 4.

##### image creation

Create such disk image with vmware version 3 or 4.

##### path

The "path" option of the ataX-xxx directive in the configuration file must point to the vmware3/4 disk image.

##### external tools

&FIXME; In addition to the utilities provided by VMware Inc. some other freeware tools are available.

##### typical use

If you want to use an existing vmware3/4 disk image.

##### limitations

Only vmware versions 3 and 4 disk image files are supported.

#### undoable

##### description

Undoable disks are commitable/rollbackable disk images. An undoable disk is based on a read-only image, associated with a growing redolog, that contains all changes (writes) made to the base image content. Currently, base images of types 'flat', 'sparse', 'growing', 'vmware3', 'vmware4' and 'vpc' are supported.

This redolog is dynamically created at runtime, if it does not previously exists.

All writes go to the redolog, reads are done from the redolog if previously written, or from the base file otherwise.

If unspecified with the "journal" option of the ataX-xxx directive, the redolog file name is created by adding a ".redolog" suffix to the base image name.

File size of the redolog can grow up to the total disk size plus a small overhead due to internal data management (about 3% for a 32MiB disk, less than 0.5% for a 2GiB disk).

After a run, the redolog will still be present, so the changes are still visible the next time you run Bochs with this disk image.

##### image creation

The base disk images must be created with the bximage utility (see using-bximage for more information). The redolog file is created automatically if it doesn't exist.

##### path

The "path" option of the ataX-xxx directive in the configuration file must be the base image name. The redolog name can be set with the "journal" option of the same directive. If not set, the redolog name is created by adding the ".redolog" suffix to the base image name.

##### external tools

To access the 'flat' mode base disk image content, see harddisk-mode-flat-tools for available tools.

The up-to-date content can only be seen after you commit the redolog to the flat file with the bximage utility.

##### typical use

- `Commit`

  After a run, the redolog can be committed (merged) to the base image with the bximage utility.

- `Rollback`

  After a run, the redolog can be rollbacked (discarded) by simply deleting the redolog file.

- `Common Base`

  One base disk image with a guest OS installed can be used to install different software as described above for the "sparse" disk image mode.

- `Harddisk Image on a Read-Only Medium`

  In the 'undoable' mode, the base file is always opened in read-only mode, so it can safely be stored on a read-only medium (for example on a CD-ROM). In that case it is recommended to specify the redolog file with the "journal" option.

##### limitations

The "undoable" disk depends on the limitations of base disk image used.

#### growing

##### description

Growing disk images start as small files, and grow whenever new data is written to them.

Once a sector is written in the growing file, subsequent writes to the same sector will happen in place.

File size of Growing disk images can go up to the total disk size plus a small overhead due to internal data management. (about 3% for a 32MiB disk, less than 0.5% for a 2GiB disk).

##### image creation

Growing disk images must be created with the bximage utility (see using-bximage for more information). Be sure to enter "growing" when selecting the image type.

##### path

The "path" option of the ataX-xxx directive in the configuration file must be the growing image name.

##### external tools

The bximage utility (see using-bximage provides convert and resize support for "growing" mode images.

##### typical use

Growing disk images can be used whenever you want to maximize disk space. However, please note that Bochs will not check if enough disk space is available before writing new data. If no disk space is available, a panic will occur.

##### limitations

The size of the virtual disk is currently limited to 8 TB, but the maximum size of the image file depends on host OS limitations.

#### volatile

##### description

Volatile disks are always-rollbacked disk images. A volatile disk is based on a read-only image, associated with a growing redolog, that contains all changes (writes) made to the base image content. Currently, base images of types 'flat', 'sparse', 'growing', 'vmware3', 'vmware4', 'vpc' and 'vbox' are supported.

The redolog is dynamically created at runtime, when Bochs starts, and is deleted when Bochs closes (win32) or just after it has been created (Unix).

All writes go to the redolog, reads are done from the redolog if previously written, or from the base file otherwise.

If unspecified with the "journal" option of the ataX-xxx directive, the redolog file name is created by adding a ".redolog" suffix to the base image name.

File size of the redolog can grow up to the total disk size plus a small overhead due to internal data management (about 3% for a 32MiB disk, less than 0.5% for a 2GiB disk).

After a run, the redolog is not any more present, so the changes are discarded.

##### image creation

The base disk images must be created with the bximage utility (see using-bximage for more information). The temporary redolog file is created automatically.

##### path

The "path" option of the ataX-xxx directive in the configuration file must be the base image name. The redolog name can be set with the "journal" option of the same directive. If not set, the redolog name is created by adding the ".redolog" suffix to the base image name. A random suffix is also appended to the redolog name.

##### external tools

To access 'flat' mode base disk image content, see harddisk-mode-flat-tools for available tools.

##### typical use

- `Repeatable simulations`

  &FIXME; to be completed

- `Multiple Bochs instances`

  &FIXME; to be completed

- `Harddisk Image on a Read-Only Medium`

  In the 'volatile' mode, the base file is always opened in read-only mode, so it can safely be stored on a read-only medium (for example on a CD-ROM). In that case it is recommended to specify the redolog file with the "journal" option.

##### limitations

The "volatile" disk depends on the limitations of base disk image used.

#### vpc

##### description

The "vpc" disk image mode is mostly a port of Qemu's "vpc" block driver for VirtualPC disk images (written by Alex Beregszaszi and Kevin Wolf).

##### image creation

Create such disk image with Microsoft VirtualPC (tm), Qemu's disk image utility (qemu-img) or bximage utility (see using-bximage for more information).

##### path

The "path" option of the ataX-xxx directive in the configuration file must point to the VirtualPC disk image.

##### external tools

Use Microsoft VirtualPC (tm) tools to manipulate these disk images.

##### typical use

Share disk images with VirtualPC.

##### limitations

The based on the Qemu code the disk size is limited to 127 GB.

#### vbox

##### description

The "vbox" disk image mode for VirtualBox disk images (VDI version 1.1) has been written by Benjamin D. Lunt.

##### image creation

Create such disk image with Qemu's disk image utility (qemu-img).

##### path

The "path" option of the ataX-xxx directive in the configuration file must point to the VirtualBox disk image.

##### external tools

Use VirtualBox tools to manipulate these disk images.

##### typical use

Share disk images with VirtualBox.

##### limitations

&FIXME; to be completed

#### vvfat

##### description

The "vvfat" disk image mode is mostly a port of Qemu's "virtual VFAT" block driver (written by Johannes E. Schindelin). It supports the read-only part of this implementation plus some additions. The structures of the virtual disk are created from the contents of the specified local directory when Bochs is starting. All writes to this virtual disk go to a volatile redolog and when closing Bochs, the user can decide whether or not to commit the changes. If "No" is seclected, all changes will be lost when Bochs quits and the files of the local directory are not modified. Otherwise, the changes of files and directories are committed. WARNING: Don't use important data without backup in the "vvfat" directory when using this "optional commit" feature.

In addition to Qemu's "vvfat" implementation the Bochs one supports configurable disk geometry, FAT32 and reading MBR and/or boot sector from file. When using the autodetection feature, the CHS values 1024/16/63 (Qemu defaults) are used. To use an MBR image file from a real disk it must be named `vvfat_mbr.bin` and placed in the specified directory. Bochs uses the geometry and file system type from this file and doesn't show it on the virtual disk. The same applies to a boot sector image file, but it must be named `vvfat_boot.bin`. Using both image file is also possible if they match (grabbed from the same disk).

FAT32 is enabled for disk with minimum 2 GB size, or if MBR / boot sector image enable this filesystem. When using "vvfat" for a floppy, FAT12 is used (1.44M media only). In all other cases FAT16 is used. Long filename support is always present.

Special FAT file attributes are stored in a special file named `vvfat_attr.cfg`. When using the "optional commit" feature, modified attributes are saved to this file. The "optional commit" also supports setting the file modification date and time.

##### image creation

Not necessary. The directory must exist before running Bochs.

##### path

The "path" option of the ataX-xxx directive in the configuration file must point to an existing local directory. The redolog name can be set with the "journal" option of the same directive. If not set, the redolog name is created by adding the filename "vvfat.dir.redolog" to the path. A random suffix is also appended to the redolog name.

##### external tools

You can use your favourite file manager to copy file to the directory you'd like to use. The directory should not be modified while Bochs is running.

##### typical use

Accessing files of the host hard drive is only possible with vvfat.

##### limitations

There is no runtime write support present yet. All changes are written to the volatile redolog and they can only be committed on Bochs exit.

When using the MBR from image file only the first partition is used and it must be of type FAT16 or FAT32. FAT12 can be used for the floppy only. An extended partition or other file system types are not supported.

The "vvfat" implementation does not support save/restore, since there is no check if the host directory tree and all files are unmodified after saving the Bochs state.

### Using the bximage tool

Bximage is an easy to use console based tool for creating, converting and resizing disk images, particularly for use with Bochs. It also supports committing redolog files to their base images. It is completely interactive if no command line arguments are used. It can be switched to a non-interactive mode if all required parameters are given in the command line.

When you run bximage without one of the following options, it will appear in interactive mode and ask for all required parameters to manipulate an image.

    Usage: bximage [options] [filename1] [filename2]

    Supported options:
      -func=...     operation to perform (create, convert, resize, commit, info)
      -fd=...       create: floppy image with size code
      -hd=...       create/resize: hard disk image with size in megabytes (M)
                    or gigabytes (G)
      -imgmode=...  create/convert: hard disk image mode
      -b            convert/resize: create a backup of the source image
                    commit: create backups of the base image and redolog file
      -q            quiet mode (don't prompt for user input)
      --help        display this help and exit

    Other arguments:
      filename1     create:  new image file
                    convert/resize: source image file
                    commit:  base image file
      filename2     convert/resize: destination image file
                    commit:  redolog (journal) file

### Bximage: supported disk images modes (formats)

Mode | Create / Resize / Convert target | Convert source / Commit base
flat | Yes | Yes
concat | Create only | Convert source only
dll | No | Convert source only
sparse | Yes | Yes
vmware3 | No | Yes
vmware4 | Yes | Yes
growing | Yes | Yes
vpc | Yes | Yes
vbox | No | Yes

Disk image mode autodetection does not work for the modes concat and dll. To use those images as convert source, you have to add a prefix ("concat:" or "dll:") to the image path.

#### Create image

This function can be used to create several disk image formats for the use with Bochs. See the table above for supported formats (modes). For an example of the usage, refer to diskimagehowto.

#### Convert image

With this function a disk image can be converted from one mode (format) to another. The type of the source image is auto-detected. For the target format it supports the same disk image modes as the create function. If the name of the new image file is not specified or identical to the source one and you have enabled the backup switch, a backup of the source file will be created with its original name plus the suffix ".orig".

#### Resize image

This function can be used to increase the virtual disk size of an image. It supports the same disk image modes as the create function. Making a disk image smaller is not supported, since it may damage the disk and data will be lost. If the name of the new image file is not specified or identical to the source one and you have enabled the backup switch, a backup of the source file will be created with its original name plus the suffix ".orig".

#### Commit 'undoable' redolog to base image

The type of the base image is auto-detected. The name of the redolog file only needs to be specified if it is not based on the base image. If you have enabled the backup switch, backups of the original base and redolog files will still be created with their original name plus the suffix ".orig".

#### Disk image info

This function can be used to determine the disk image format, geometry and size. Note that Bochs can only detect the formats growing, sparse, vmware3, vmware4, vpc and vbox correctly. Other images with a file size multiple of 512 are treated as flat ones. If the image doesn't support returning the geometry, the cylinders are calculated based on 16 heads and 63 sectors per track.

## Guest operating systems

In the past several tweaks were necessary to install a guest OS inside of Bochs. Nowadays, it is almost the same as installing it on a real machine. There are only a few Bochs specific issues you should know about. Note that we cannot give you a full installation guide if you don't know how to install an OS in the real world. The following remarks apply to all guest OS installations. Some specific issues are reported in the next sections.

- First of all, you need the installation media or image (floppy/CD/DVD). For platforms that don't support raw device access it might be necessary to create an image from the media. Please read the message regarding software licenses in thirdparty before you install or use a commercial guest operating system in Bochs.

- Then you need to create a hard drive image with bximage. For the required size see the documentation of the OS you'd like to install. See using-bximage how to create the image.

- Finally you have to create configuration for your guest OS. You can edit the sample configuration distributed with Bochs or use the configuration interface to adjust the settings. Check the documentation of your guest OS for the required memory size, cpu speed and supported hardware.

Now you should be able to run Bochs and start the installation process. Depending on the host cpu speed and the size of the guest OS it can take a few minutes or even some hours.

    What disk images are available.
    What works
    Known problems

### Knoppix

Contributed by Alexander Schuch.

#### Getting Knoppix

Knoppix is a live CD (700M) or live DVD (3.2G) based on Debian GNU/Linux, with lots of ready-to-run programs (web browser, office suite, a few games, and more), using KDE as desktop environment. It can be booted directly from CD, without any installation needed. You can download it from knoppix.org.

#### Preparing Bochs

As Knoppix runs completely from CD/DVD, you don't need to setup a hard disk. You just need to set up the location of the downloaded ISO image in your `bochsrc`, and make Bochs boot from it. Because Knoppix contains a graphical user interface, and has no other storage space but the emulated RAM, it needs at least 128MB of it, see megs option. Furthermore, you need to enable VBE support in Bochs (see vesa-notes).

#### Using Knoppix

There is nothing more to do! Just start Bochs and wait for Knoppix to load...

You are logged in as normal user, if you want to become super user, just `su`. There is no password needed (empty password).

### FreeBSD 5.2.1

Contributed by Alexander Schuch.

This section describes how to install FreeBSD 5.2.1 (miniinst) inside of Bochs, using an ISO image.

#### Getting FreeBSD

As `5.2.1-RELEASE-i386-miniinst.iso` (240M) is no longer available from the FreeBSD FTP server, you might want to ask a (file) search engine of your choice for a download location. Once you downloaded the file, you should check its integrity using the provided MD5 checksum from the FreeBSD 5.2.1 release announcement.

#### Preparing Bochs

Create a new hard disk image using `bximage` (see using-bximage) with a size of at least 350M, as the standard installation uses 280M on its own.

Next, you need to setup your `bochsrc` so that Bochs knows about your (still empty) hard disk, as well as about your ISO image. Make Bochs boot from CD-ROM and start the emulation.

#### Installing FreeBSD

This is just a very short step-by-step installation guide for FreeBSD in Bochs. It doesn't explain what you do nor why you do it, it just tells you how to do it. For in-depth information refer to the FreeBSD handbook: Installing FreeBSD.

FreeBSD boots up and shows a nice (text-mode) boot option screen. Just press return there, that is, use the default option. After loading the kernel and needed device drivers, select 'Standard' in the installation menu.

A fdisk like partition program is loaded next, where you just press A to use the entire disk, followed by Q to finish the selection. The next dialog asks for the boot manager you want to use. Select 'Standard' and continue.

In the Disklabel Editor, you have to setup the layout of your partition. If your (virtual) hard disk is large enough, you can press A for auto-layout. However, you need to make sure that the `/usr` partition is at least 250M large, or you will end up with a 'disk full' error message during installation. If this is not the case, select one partition after another and press D to delete it again. After you deleted all partitions, create two new ones. The first one will be a swap partition; press C, enter '32M' as size and select 'Swap' from the dialog. Press C again, and accept the remaining capacity for your filesystem partition. Choose 'FS' as partition type and enter '/' (slash) as mount point. Your partition layout is complete now; press Q to leave the editor.

This 'all-in-one' partition layout is not recommended for a FreeBSD installation on a real box; use 'auto-layout' or something comparable to that there.

You now can choose what set of programs/files (distribution) you want to install. Take 'User' (option 8), and select 'No' when asked to install the ports collection. You are back in the distribution selection, where you select the first item, called 'Exit'. Choose to install from 'CD/DVD' and answer the 'Are you sure?' dialog with 'yes'.

Now, while FreeBSD installs, it is a very good time to take a look at the FreeBSD documentation, especially the FreeBSD handbook and the FreeBSD FAQ.

#### Post-installation configuration

All files are installed on your (virtual) hard disk now, and FreeBSD is ready for getting set up. As this is a very basic FreeBSD installation, you just answer 'no' to nearly all questions, but the one about your mouse: Answer 'yes' for PS/2 mouse, and choose 'Exit' at mouse configuration. The minimalist FreeBSD ISO image contains nearly no binary packages, so don't browse the package collection. Then, when asked to create a new user account, answer 'yes' and create a new user called 'bochs' (or whatever you like). You might want to use `/bin/csh` or `/bin/tcsh` as shell rather than `/bin/sh`. Next, you are asked for the super user (root) password. The installation is finished now, there is no need to visit the general configuration menu again - answer 'no' to that question. FreeBSD will then reboot. Shutdown Bochs, as soon as the (virtual) computer boots.

#### Using FreeBSD

Open your `bochsrc` and change the boot sequence, so that Bochs will boot from hard disk, rather than from CD-ROM from now on. Start Bochs again and watch the FreeBSD boot process.

Your keyboard might use the wrong keymap, so login (into FreeBSD) as super user and use `/stand/sysinstall` to start the FreeBSD configuration program. Choose 'keymap' and select the keymap you want to use.

You have successfully installed FreeBSD now. You might want to shutdown FreeBSD using `shutdown -h now`, quit Bochs, and create a backup of your hard disk image, before you start playing around.

### DOS

Please read the message regarding software licenses in thirdparty before you install or use MS-DOS, DR-DOS, FreeDOS or any other DOS as a guest operating system in Bochs.

#### Accessing your CD-ROM

To access your CD-ROM in DOS, you must download an IDE CD-ROM driver. Bochs emulates a very generic CD-ROM drive, and several drivers are known to work. Others don't. This section describes how to set up your `config.sys` and `autoexec.bat` to enable the CD-ROM.

The drivers that have been reported to work are `OAKCDROM.SYS` that comes with several versions of Windows and `SBIDE.SYS` version 1.21 from Creative Labs

To get it, go to Creative Labs web site, click on Support, then click Download Files. You get to a screen where you must select the operating system and the product for which you want the driver. Choose DOS as the operating system, and "CD-ROM: 4x and above" as the product. There are several choices, but you want `sbide121.exe` from April 15, 1997. Version 2.0 does not work. The download file is a self-extracting ZIP file, so on DOS or Windows you just run it; on other platforms you can try using the unzip command. The driver is called SBIDE.SYS.

. Copy the driver to your boot disk, and then set up the startup files as follows:

    config.sys:
      device=himem.sys
      device=oakcdrom.sys /D:CD001
          -or-
      device=sbide.sys /D:CD001 /P:1f0,14,3f6

    autoexec.bat:
      mscdex.exe /M:10 /D:CD001

If the files mentioned in `config.sys` and `autoexec.bat` are not in the root directory, give the full pathname, like `c:\windows\himem.sys`.

#### SB16 driver for DOS

To use the SB16 device in DOS you need to load a driver for it. The file `SBBASIC.EXE` contains a self-extracting archive with all required file. After unpacking it to `C:\SB16` you can execute `INSTALL.EXE` to install the driver. The file `DISK.ID` should contain the version string `SDR-31STD-1-US (Revision 1)`.

#### Bootdisks of early DOS versions

On the Web, there are bootdisks available for most of the DOS versions ever released, but some of them have been reported to fail in Bochs. The bootdisk for MS-DOS 1.25 contains a boot sector of a newer DOS version, so it would fail on real hardware, too. The floppy image for MS-DOS 2.11 has a boot sector that tries to boot from hard disk instead of the floppy.

### Windows 95

Contributed by Benjamin David Lunt

Please read the message regarding software licenses in thirdparty before you install Windows 95 as a guest operating system in Bochs.

Windows 95 has been reported to install from the CD-ROM, and run inside Bochs. Here are a few settings that seem to work well when running on a Windows10 host, running at 3.0Ghz.

    romimage: file=D:/path/to/your/bios/BIOS-bochs-latest
    cpu: model=broadwell_ult
    cpu: count=1, ips=50000000, reset_on_triple_fault=1, ignore_bad_msrs=1
    cpu: cpuid_limit_winnt=0
    clock: sync=realtime, time0=local
    memory: guest=512, host=512
    vgaromimage: file=D:/path/to/your/bios/VGABIOS-lgpl-latest-cirrus
    vga: extension=cirrus, update_freq=5
    pci: enabled=1, chipset=i440fx, slot1=cirrus

### Windows 98SE

Contributed by Benjamin David Lunt

Please read the message regarding software licenses in thirdparty before you install Windows 98 as a guest operating system in Bochs.

Windows 98SE has been reported to install from the CD-ROM, and run inside Bochs. Here are a few settings that seem to work well when running on a Windows10 host, running at 3.0Ghz.

    romimage: file=D:/path/to/your/bios/BIOS-bochs-latest
    cpu: model=corei7_haswell_4770
    cpu: count=1, ips=55000000, reset_on_triple_fault=1, ignore_bad_msrs=1
    cpu: cpuid_limit_winnt=0
    clock: sync=realtime, time0=local
    memory: guest=512, host=512
    vgaromimage: file=D:/path/to/your/bios/VGABIOS-lgpl-latest-cirrus
    vga: extension=cirrus, update_freq=5
    pci: enabled=1, chipset=i440fx, slot1=cirrus

### Windows NT 4.0

Please read the message regarding software licenses in thirdparty before you install Windows NT 4.0 as a guest operating system in Bochs.

Here are the known issues about installing and running Windows NT4.0 :

- If you want to use the LGPL'd VGABIOS to install Windows NT 4.0 you'll need version 0.4c or higher. With older versions you'll get a black screen after first reboot.

- to log in you must press ctrl-alt-del, and it is likely that the window manager will trap this key combination. You can either use the trick described in enter-special-keys or define a user short-cut (callable through the user short-cut GUI button) in you configuration file, for example:

      keyboard: user_shortcut=ctrl-alt-del

- For installing and using Windows NT it is necessary to limit the maximum CPUID to 3. In the configuration file you need to add a line like this:

      cpuid: cpuid_limit_winnt=1

### Windows 2000 / Windows 2000 Server

Please read the message regarding software licenses in thirdparty before you install Windows 2000 / Windows 2000 Server as a guest operating system in Bochs.

### Windows XP

Contributed by Benjamin David Lunt

Please read the message regarding software licenses in thirdparty before you install Windows XP as a guest operating system in Bochs.

Windows XP has been reported to install from the CD-ROM, and run inside Bochs. Here are a few settings that seem to work well when running on a Windows10 host, running at 3.0Ghz.

    romimage: file=D:/path/to/your/bios/BIOS-bochs-latest
    cpu: model=broadwell_ult
    cpu: count=1, ips=75000000, reset_on_triple_fault=1, ignore_bad_msrs=1
    cpu: cpuid_limit_winnt=0
    clock: sync=realtime, time0=local
    memory: guest=512, host=512
    vgaromimage: file=D:/path/to/your/bios/VGABIOS-lgpl-latest-cirrus
    vga: extension=cirrus, update_freq=5
    pci: enabled=1, chipset=i440fx, slot1=cirrus

A known issue is to set the IPS value to less than 10,000,000 (minus the commas). WinXP doesn't run well at an IPS setting less than 10Mips.

Also don't set it to more than 250,000,000. Anything faster and WinXP seems to stall within the CPU loop function. WinXP seems to work well with an IPS setting of 75,000,000 on a 3.0Ghz host.

The 64-bit version of WinXP needs Bochs compiled with ACPI support even though you only set to one CPU.

For some reason, writing to a USB disk in WinXP, where the write takes a little while, WinXP will think it is an error since it didn't complete fast enough, displaying the error. I don't know why.

### Windows 7

Contributed by Benjamin David Lunt

Please read the message regarding software licenses in thirdparty before you install Windows 7 as a guest operating system in Bochs.

Windows 7 has been reported to install from the CD-ROM, and run inside Bochs. Here are a few settings that seem to work well when running on a Windows10 host, running at 3.0Ghz.

    romimage: file=D:/path/to/your/bios/BIOS-bochs-latest
    cpu: model=broadwell_ult
    cpu: count=1, ips=100000000, reset_on_triple_fault=1, ignore_bad_msrs=1
    cpu: cpuid_limit_winnt=0
    clock: sync=realtime, time0=local
    memory: guest=1024, host=1024
    vgaromimage: file=D:/path/to/your/bios/VGABIOS-lgpl-latest-cirrus
    vga: extension=cirrus, update_freq=5
    pci: enabled=1, chipset=i440fx, slot1=cirrus

Don't set it to more than 250,000,000. Anything faster and Win7 seems to be sluggish, but seems to work well with an IPS setting of 100,000,000 on a 3.0Ghz host.

### Windows 8

Contributed by Benjamin David Lunt

Please read the message regarding software licenses in thirdparty before you install Windows 8 as a guest operating system in Bochs.

Windows 8 has been reported to install from the CD-ROM, and run inside Bochs. Here are a few settings that seem to work well when running on a Windows10 host, running at 3.0Ghz.

    romimage: file=D:/path/to/your/bios/BIOS-bochs-latest
    cpu: model=broadwell_ult
    cpu: count=1, ips=150000000, reset_on_triple_fault=1, ignore_bad_msrs=1
    cpu: cpuid_limit_winnt=0
    clock: sync=realtime, time0=local
    memory: guest=2048, host=2048
    vgaromimage: file=D:/path/to/your/bios/VGABIOS-lgpl-latest-cirrus
    vga: extension=cirrus, update_freq=5
    pci: enabled=1, chipset=i440fx, slot1=cirrus

Don't set it to more than 250,000,000. Anything faster and Win8 seems to be sluggish, but seems to work well with an IPS setting of 150,000,000 on a 3.0Ghz host.

### Windows 10

Contributed by Benjamin David Lunt

Please read the message regarding software licenses in thirdparty before you install Windows 10 as a guest operating system in Bochs.

Windows 10 has been reported to install from the CD-ROM, and run inside Bochs, though a few hacks where used to do so. For more information, see this thread.

I used another emulator to successfully install Windows 10. Then using Bochs, after a considerable amount of time and a few reboots, I finally got Win10 to boot and load in Bochs.

Here are the settings I used when running on a Windows10 host, running at 3.0Ghz.

    romimage: file=D:/path/to/your/bios/BIOS-bochs-latest
    cpu: model=corei7_sandy_bridge_2600k
    cpu: count=1, ips=325000000, reset_on_triple_fault=1, ignore_bad_msrs=1
    cpu: cpuid_limit_winnt=0
    clock: sync=realtime, time0=local
    memory: guest=2048, host=2048
    vgaromimage: file=D:/path/to/your/bios/VGABIOS-lgpl-latest-cirrus
    vga: extension=cirrus, update_freq=5
    pci: enabled=1, chipset=i440fx, slot1=cirrus

If you use an IPS value less than 325,000,000, Win10 will BSOD and want you to reboot (Assuming a host at 3.0Ghz).

### SCO OpenServer 5.0.5

Contributed by Carl Sopchak

Please read the message regarding software licenses in thirdparty before you install SCO OpenServer 5.0.5 as a guest operating system in Bochs.

Back in April and May of 2002, I did some work on Bochs in order to get it to install and boot SCO's OpenServer 5.0.5 (OSR5). Since that time, I have had several e-mails asking about this error message or that. The newsgroup posts done at the time had all of the information that I knew, so I pointed people there. (I had not used Bochs since...) In February of 2003, I got another such e-mail. Since the sender indicated they were willing to pay me to get this going for them, I agreed to spend a few hours on it (for free, which is not common :-}). Subsequently, I decided to document this once and for all. (I did not charge anyone anything, this time...)

Note: These steps were originally used with Bochs 1.4.1 (or thereabouts, since I was using CVS heavily at the time). It is possible (likely) that later versions of Bochs are more tolerant/bug free, and this install may be abbreviated. However, I have not tried to streamline it at all.

These steps were performed and confirmed using Bochs version 2.0.2, and SCO OpenServer version 5.0.5. The host OS was Red Hat Linux 8.0.

First, I downloaded the tarball, and extracted the source tree. I decided to use the tarball instead of the RPM so that I knew what options were compiled in, etc.

    linux-$ tar -xzvf bochs-2.0.2.tar.gz

Next, I configured and compiled Bochs...

    linux-$ cd bochs-2.0.2
    linux-$ ./configure --enable-cdrom --enable-ne2000
    linux-$ make

I then created my disk image:

    linux-$ ./bximage
    ========================================================================
                                    bximage
                      Disk Image Creation Tool for Bochs
    ========================================================================

    Do you want to create a floppy disk image or a hard disk image?
    Please type hd or fd. [hd] hd

    What kind of image should I create?
    Please type flat, sparse or growing. [flat]

    Enter the hard disk size in megabytes, between 1 and 8257535
    [10] 2048

    I will create a hard disk image with
      cyl=4161
      heads=16
      sectors per track=63
      total sectors=4194288
      total size=2047.99 megabytes

    What should I name the image?
    [c.img] hd0.img

    Writing: [] Done.

    I wrote 2147475456 bytes to hd0.img.

    The following line should appear in your .bochsrc:
      ata0-master: type=disk, path="hd0.img", cylinders=4161, heads=16, spt=63

I then created my .bochsrc file. I did this via the interactive portion of Bochs, with the end result as follows:

    floppya: 1_44="/dev/fd0", status=inserted
    floppyb: 1_44="b.img", status=inserted
    ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
    ata0-master: type=disk, path="hd0.img", cylinders=4161, heads=16, spt=63, translation=auto, biosdetect=auto, model="Generic 1234"
    ata0-slave: type=cdrom, path="/dev/cdrom", status=inserted, biosdetect=auto, model="Generic 1234"
    ata1: enabled=0
    ata2: enabled=0
    ata3: enabled=0
    romimage: file=bios/BIOS-bochs-latest
    vgaromimage: file=bios/VGABIOS-lgpl-latest
    megs: 64
    parport1: enabled=1, file="lp.pipe"
    com1: enabled=0
    # no sb16
    boot: cdrom
    floppy_bootsig_check: disabled=0
    vga: update_freq=5
    keyboard_serial_delay: 250
    keyboard_paste_delay: 100000
    cpu: ips=3000000
    clock: sync=realtime, time0=0
    mouse: enabled=0
    private_colormap: enabled=0
    pci: enabled=0
    # no ne2k
    # no loader
    log: osr5.log
    logprefix: %t-%e-%i%d
    debugger_log: -
    panic: action=ask
    error: action=report
    info: action=report
    debug: action=ignore
    keyboard: type=mf, keymap=, user_shortcut=none
    config_interface: textconfig
    display_library: x

Some important things to note are that you want to boot from the CD-ROM, and you do NOT want the ne2000 card configured initially. (We'll add that later...)

At this point, Bochs is ready to roll! Insert the OSR5 install CD into the drive, and start Bochs. You should soon see the SCO "boot:" prompt:

    SCO OpenServer(TM) Release 5

    boot
    : defbootstr disable=fdi,dptr

Note the disable= parameter that you need. These two SCO drivers cause the install to fail, so they need to be disabled for the install boot. You will not need this once OSR5 is installed.

During the install of OSR5, there are two default configuration answers that need to be changed. For the hard disk setup, you should turn bad tracking off, since it's unnecessary on an emulated disk. (It won't hurt to do it, it will just take a VERY long time!) For the network setup, change the network card to Deferred. You can change other settings, if you so desire. However, I would do the initial install with as little configured as you can get away with, then add whatever else is needed (one step at a time) after the initial install completes.

Let the install copy the files. Go get lunch. Take a nap. Go have dinner... This can take a LONG time. On my Pentium 4 1.7GHz system, this step took just over eight hours! (BTW, it was MUCH longer in version 1.4.1. Great job, guys!)

After the install finishes, you will need to change the following lines in .bochsrc file:

    ne2k: ioaddr=0x300, irq=10, mac=b0:c4:20:00:00:00, ethmod=linux, ethdev=eth0
    boot: disk

Obviously, if you're not using Linux, the ethmode and ethdev values on the ne2k line will be different. Also, since Bochs uses "raw" network card access, you'll have to "setuid root" on the Bochs executable:

    linux-$ chown root bochs
    linux-$ chmod u+s bochs

(If there is a way to give a "normal user" CAP_NET_RAW capability, that would be an alternative. I don't know how to do that...) Restart Bochs. Now, you can just press Enter at the OSR5 boot: prompt, because the offending drivers have been linked out of the kernel.

Before you configure the network card, I'd strongly suggest getting the latest "nat" driver from SCO. Version 5.0.5b of this driver, according to the SCO web site, "correct[s] possible system lockup under high load due to internal buffer overflow." The driver can be found here. To get the Disk Image file into SCO, I downloaded the VOL.000.000 file to my linux box, and used tar to get it on to a floppy:

    linux-$ tar -cvf /dev/fd0 VOL.000.000

I then used tar within OSR5 to move it from the floppy to the /tmp directory:

    osr5-# cd /tmp
    osr5-# tar -xvf /dev/fd0135ds18

You can then use 'custom' to install the driver from the image file. You will then want to use 'scoadmin network' to configure the network card. Choose the Novell NE2000 card, and set the parameters to match the ne2k: line in the .bochsrc file. DO NOT have OSR5 look for the card, as Bochs may likely crash. (It did in version 1.4.1.)

You can also configure a printer, if you want. Using the spoolpipe utility that I wrote (which can be found in Bochs' misc directory), you can print from OSR5 through the parallel port, and you'll hardly notice that the printing is going through an extra layer of operating system! (You could also set up a printer using network printing, if the printer is not on the host machine...)

Obviously, don't forget to apply the release supplements and other patches that are considered "must haves" for OSR5: rs505a, oss600a, oss497b (others?).

That's about as far as I have got. I played around with OSR5 within Bochs a bit, but I can by no means say that I did any kind of real testing, let alone exhaustive testing.

And of course, YMMV! :-)