MS-DOS EXE

Revision as of 19:31, 13 September 2016

MZ (also called by its extension EXE and by other names) is an executable file format used mainly by MS-DOS; the format is a successor of COM.

Many other executable formats are extensions of MZ, including New Executable (used by 16-bit Windows), Portable Executable (newer Windows versions) and Linear Executable (OS/2). Files in these formats usually begin with a short MZ program (called a DOS stub) which, when executed by DOS, prints a message like "This program cannot be run in DOS mode" or "This program requires Microsoft Windows" and immediately exits. Some programs contain a more functional DOS stub, e.g. the Windows 9x registry editor.

Identification

An MZ file begins with an ASCII signature of 'M' 'Z' (or, rarely, 'Z' 'M'), 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.

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