Squeeze
From Just Solve the File Format Problem
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* [[CFX]] (DOS/Unix) | * [[CFX]] (DOS/Unix) | ||
| + | * [http://www.svgalib.org/rus/lbrate.html lbrate] (Unix) | ||
* On CP/M (or emulators): | * On CP/M (or emulators): | ||
** The original tools were SQ/USQ. See for instance the [http://www.classiccmp.org/cpmarchives/cpm/mirrors/oak.oakland.edu/pub/cpm/squsq/ SQUSQ] directory of the Oakland CP/M archive. | ** The original tools were SQ/USQ. See for instance the [http://www.classiccmp.org/cpmarchives/cpm/mirrors/oak.oakland.edu/pub/cpm/squsq/ SQUSQ] directory of the Oakland CP/M archive. | ||
Revision as of 11:05, 27 January 2013
Squeeze was a method of compressing single files popular on CP/M, devised by Richard (Dick) Greenlaw(?) circa 1981. It was superseded by Crunch and later CrLZH. Squeezed files were common in LBR archives. It uses Huffman compression.Squeezed files were signified in CP/M's 8.3 filename format by replacing the middle letter of the extension with Q (.?Q? -- so FOO.TXT became FOO.TQT), with the extension .QQQ used for corner cases such as a blank extension.
The /usr/share/misc/magic file on Linux systems suggests that it was perhaps also in use on the Apple ][ platform.
Tools
References
- See the SQUSQ directory on CP/M archives for various source code and documentation (much of it, unfortunately, itself squeezed/crunched).
- The file header follows a similar/compatible structure to Crunch and CrLZH.
- FIXME: is the exact compression algorithm documented anywhere?
- Wikipedia:SQ (program)
