AceDB database.wrn syntax

## AceDB database.wrm syntax

on the line in interpreted according to the keyword. Current Keywords:

- PART
- NAME
- SESSION_KEEP_ALIVE
- READLOCK_TIMEOUT
- NOLOCK
- SYNC_WRITE

note :

- lines beginning by // are comments
- a line don't exeed 512 characters.

PART = partition

Example:

    //Keyword : type hostname partition_name file_name          max_size offset
    PART :       1   local    ACEDB          block1.wrm          5000      0
    PART :       1   local    ACEDB          block2.wrm          20000     0

partition types :

- UNIX_FILE_SYSTEM = 1
- RAW_FILE_SYSTEM = 2

hostname
partition_name
  full path or "ACEDB" if relative to ACEDB variable.
file_name
  only for unix file system : name of the partition file. for other types, "NONE"

`NAME`
  is database name, this is set in the database super block when the database is rebuilt. It can only be changed by rebuilding the database and can be used as a reliable identifier for the database. This name is used in the main window header and in status output.
`TITLE`
  is an additional database name that is reread each time the database is restarted. It can be used to give a more temporary title to a database to give more information about the database. This title is used in the main window and will override the main window title in wspec/displays.wrm, its also used in the status output.
`SESSION_KEEP_ALIVE`
  is the number of sessions to keep alive after saving an update to the database. This number must be at least 1, the code uses the default 2, if this value isn't set. 3 or 4 are also sensible. If this number is much bigger than that, the amount of diskspace taken up by data of old sessions that are kept alive, may be a considerable penalty.
`READLOCK_TIMEOUT`
  is the time in hours after which a readlock is regarded as a left-over from a crash process. Any readlock older than that will be removed and ignored by the current and all subsequent acedb programs. For newer version (>= 4.8) which clean up readlocks even after unforseen crashes this number may be quite small (even as low as 2 or 3), because readlocks of genuinely running processes are continuously restored. A recommended safe number is 8 to 12 depending on usage of the database.
`NOLOCK`
  On some platforms the Unix style lockf() system call is either not supportd or is bugged. In this case you may want to uncomment the NOLOCK line to prevent it being used. Note that this disables one of the multiple access checks. It therefore makes corruption of the database by simultaneous access over the network more possible. This is particularly a problem with an nfs mounted database, because NFS buffering can bypass the other acedb protections.
`SYNC_WRITE`
  If acedb databases are accessed via NFS, writes to the database can time out and fail _WITHOUT_ acedb being able to detect this. This can lead to corruption of the database. Uncommenting the below line will force acedb to open database files for writing in synchronous mode. This will slow down the writes by a factor of at least 5, _but_ acedb will be able to detect when writes via NFS fail. You may need to do this if your network becomes very overloaded but you still need to be able to update the database reliably.