MS-DOS EXE

MS-DOS EXE is an executable file format used mainly by MS-DOS. It is the successor to COM.

Its name has many variations, such as DOS MZ executable. It is also called MZ, though that name might include hybrid formats (NE, PE, etc.) that also use the "MZ" signature.

Identification
An MS-DOS EXE file begins with an ASCII signature of " ". The 16-bit integer at offset 24 is usually (but apparently not always) less than 64.

It's not clear whether there is any completely reliable way to identify an MS-DOS EXE, except in the negative (i.e. it begins with "MZ", and is not a valid NE, PE, etc., file).

Links

 * Wikipedia article
 * MZ, from the OSDev Wiki
 * http://www.delorie.com/djgpp/doc/exe/