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.
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.