Freeze/Melt
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'''Freeze''' is a file compression utility used from the command line in Unix-style operating systems. '''Melt''' is the corresponding decompressor. It is considered obsolete now in favor of [[gzip]]. | '''Freeze''' is a file compression utility used from the command line in Unix-style operating systems. '''Melt''' is the corresponding decompressor. It is considered obsolete now in favor of [[gzip]]. | ||
| − | A two-pass compression is done with a [[Lempel-Zev]] algorithm on the first pass and a dynamic [[Huffman | + | A two-pass compression is done with a [[Lempel-Zev]] algorithm on the first pass and a dynamic [[Huffman coding|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). |
== References == | == References == | ||
* [http://www.esrl.noaa.gov/gmd/dv/hats/cats/stations/qnxman/freeze.html Man page] (in NOAA site, which should know something about freezing!) | * [http://www.esrl.noaa.gov/gmd/dv/hats/cats/stations/qnxman/freeze.html Man page] (in NOAA site, which should know something about freezing!) | ||
* [http://reality.sgiweb.org/freeware/source/freeze-2.3.1/ Source code] | * [http://reality.sgiweb.org/freeware/source/freeze-2.3.1/ Source code] | ||
Revision as of 14:49, 23 February 2013
Freeze is a file compression utility used from the command line in Unix-style operating systems. Melt is the corresponding decompressor. It is considered obsolete now in favor of gzip.
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).
References
- Man page (in NOAA site, which should know something about freezing!)
- Source code
