Freeze/Melt

File Format
Name	Freeze/Melt
Ontology	Electronic File Formats Compression Freeze/Melt
Extension(s)	.F, .f, .lzc
Released	≤1991

See Freeze for other formats with that name.

Freeze is a file compression utility used from the command line in Unix-style operating systems. Melt is the corresponding decompressor. The format is sometimes called "frozen". It was developed by Leonid A. Broukhis. It is considered obsolete now in favor of gzip.

Format details

A two-pass compression is done with a Lempel-Zev algorithm on the first pass and a dynamic Huffman algorithm on the second. The characteristics of the Huffman table used are added to the file. File attributes, ownership, etc., are preserved, and a .F extension is added. A two-byte magic number is prepended to the file (\037\236 octal for versions 1.x, and \037\237 for later versions).

Software

• Source code
• Versions 2.1–2.5 were posted to the comp.sources.misc Usenet group in 1991–1993:
  • [1], [2], [3]
  • Source Code CD ROM (Walnut Creek) (March 1994)

References

• Man page (in NOAA site, which should know something about freezing!)