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# How Windows NT Recognizes MS-DOS - Based Applications

Article ID: 102057

Article Last Modified on 10/31/2006

APPLIES TO

- Microsoft Windows NT Advanced Server 3.1
- Microsoft Windows NT Workstation 3.1
- Microsoft Windows NT Advanced Server 3.1

This article was previously published under Q102057

## SUMMARY

Windows NT recognizes a file as an MS-DOS - based application and gives it to the MS-DOS subsystem if the file meets the following criteria:

- It is a .COM file.
- It is an .EXE file and has no extended header (that is, no NE signature).
- It is an .EXE file and has an extended header with an LE signature.
- It is an .EXE file, has an NE signature, but there is no DOSCALLS.DLL in the import table
- It is an .EXE file, has an NE signature, but no special signatures, such as:
  - ExeType in the extended header equal to 5 (DOS4.0)
  - No import table entry
  - "mode EXE$" signature in the extended header (Borland application)
  - "16STUB" signature in the extended header (Borland application)
  - "Phar Lap Software, Inc." signature in the extended header (Phar Lap extended header)
  - "Copyright (C) Rational Systems Inc." signature in the extended header (rational extended header)
  - Lotus 1-2-3 preloader signature of (certain version of 123.EXE)

Additional query words: prodnt

Keywords: kbinterop kb3rdparty KB102057