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 It was superseded by Crunch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, and in fact Binary II files are often found squeezed (as .bqy instead of .bny). Versions for PC/MS-DOS were also in use in the early 1980s before ARC caught on as the dominant archiver.
- CFX (DOS/Unix)
- lbrate by Russell Marks, c. 2001 (Unix, GPL2)
- On CP/M (or emulators):
- The original tools were SQ/USQ. See for instance the SQUSQ directory of the Oakland CP/M archive.
- The later LT31 deals with extracting from all of Squeeze, Crunch, CrLZH and LBR formats. Widely available in CP/M archives, e.g. LT31.LBR
- 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)