The MS-DOS COM Executable File Format
The COM files are raw binary executables and are a leftover from the old CP/M
machines with 64K RAM. A COM program can only have a size of less than one
segment (64K), including code and static data since no fixups for segment
relocation or anything else is included. One method to check for a COM file is
to check if the first byte in the file could be a valid jump or call opcode, but
this is a very weak test since a COM file is not required to start with a jump
or a call. In principle, a COM file is just loaded at offset 100h in the segment
and then executed.
OFFSET Count TYPE Description
0000h 1 byte ID=0E9h
Those are not safe ways to determine wether a
file is a COM file or not, but most COM files
start with a jump.
Further information not available.
SEE ALSO:EXE,MZ EXE,NE EXE
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