MIDAS uses the FITS format as the main data import/export format. 
Images, tables and fit files in FITS format can be read into MIDAS via the 
commands INTAPE/FITS, INDISK/FITS or INDISK/MFITS (for FITS files with many
extensions).
Since the 11SEPpl1.0 release, Midas also reads FITS files with unsigned 
32bit integer data.
However, since that format is not supported in Midas internally, such data
are converted to double precision in Midas.
Also, Midas FITS does not support BITPIX=64 nor full usage of BLANK values
in integer formats.
Use Midas> HELP Midas-command to get the details.

FITS files (images, tables) can be accessed (and modified) directly in MIDAS, 
i.e. you don't need to execute INDISK/FITS on such a file, just use it like 
any MIDAS file. However, FITS images are always mapped fully into
memory. That's no problem if you use commands which just work on one or two 
images, but for e.g. commands like AVERAGE/IMAGE you could end up allocating 
a LOT of memory when working with FITS files directly...
Also extensions of FITS files can be accessed (but not modified) directly in
MIDAS. For the relevant syntax, see he help of the topic [Filenames].
 
Images stored as ASCII data files can be read into MIDAS via the INDISK/ASCII
command or CREATE/IMAGE with the ASCII_file option.
For ASCII tables use the command CREATE/TABLE.
Use HELP INDISK/ASCII, HELP CREATE/IMAGE and HELP CREATE/TABLE to get 
the details.
 	        
Some programs, like e.g. "xv", already convert directly any of the major
image formats to FITS.
