Format

MS-DOS Compression Format (SZDD Variant)

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Summary

Name: MS-DOS Compression Format (SZDD Variant)
Identifiers: PUID: fmt/462
Format type: Aggregate
Description: The MS-DOS compression format uses the SZDD algorithm to compress a single file into another single file, replacing the last character in the filename with an underscore. It is implemented via the MS-DOS commands COMPRESS.EXE and EXPAND.EXE.
Note: A DOS compressed file will be named file.**_, so a DOS compressed .exe will be named 'file'.ex_, a DOS compressed .jpg will be named 'file'.jp_. https://www.cabextract.org.uk/libmspack/doc/szdd_kwaj_format.html
Submitted by: Digital Preservation Department / The National Archives

Internal signatures

MS DOS Compression (SZDD)

Description: BOF: SZDDˆð'3A
Provenance: Source: Files from TNA Digital Archive, http://www.cabextract.org.uk/libmspack/doc/szdd_kwaj_format.html

Byte sequences

Min Frag Length: Absolute from BOF
Offset: 0
Max offset: None
Byte Sequence: 535A444488F0273341
Endianness: None

Changelog

V109

Release date

1 November 2022
- Updated
  
  MS-DOS Compression Format (SZDD Variant): Changed filetype to Aggregate. Submitted by National Library of the Netherlands.
V103

Release date

11 March 2022
- Updated
  
  MS-DOS Compression Format (SZDD Variant): Amended name for consistency, added link and description. Submitted by IS4.
V91

Release date

25 July 2017
- Updated
  
  MS DOS Compression Format: Removed empty 'External Signature' - should be null instead. Error identified through schema validation work with French government/Programme Vitam, France
V62

Release date

28 August 2012
- Added format
  
  MS DOS Compression Format: Outline Entry Added.
- Added signature
  
  MS DOS Compression Format: Signature developed through PRONOM Research.