MS-DOS EXE

File Format
Name	MS-DOS EXE
Ontology	Electronic File Formats Executables MS-DOS EXE
Extension(s)	.exe
PRONOM	x-fmt/409

MS-DOS EXE, also known as MZ format, is an executable file format used mainly by MS-DOS. It is the successor of COM. A number of other executable formats are extensions of it; see EXE for those formats.

Identification

An MS-DOS EXE file begins with an ASCII signature of "MZ" (or, rarely, "ZM"), followed by a series of 16-bit fields. The field at offset 24 (the relocation table offset) is usually (but apparently not always) less than 64, and at least 28. A value of 64 or more, or 0, suggests the format may not be MS-DOS EXE.

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/
• DOS EXE format
• EXE Explorer utility
• Ralf Brown's Interrupt Reference has an extensive list of (mostly older) MZ-based executable formats