Gzip

See also: Zip

gzip (Acronym of ''' G ''' NAKED zip ), is a Free software, open standard, utility of compression, which was created to replace the program compress of Unix.

gzip is based on the algorithm Deflate , which is a combination of the algorithms LZ77 and Huffman. “Deflate” was developed in answer to problems of covering patent LZW and other algorithms of compression, thus limiting the possible uses of compress and other popular programs of filing.

So as to simplify the developments of software using compression, the library Zlib was created. It supports the format of file gzip and the algorithm of compression deflate . This library is very largely used, thanks to its reduced size, its effectiveness and its flexibility in use. gzip as Zlib was written by Jean-Wolf Gailly and Mark Adler. Since the end of the year 1990, Bzip2 takes over since it produces files considerably smaller.

The format of compressed data Zlib, the algorithm deflate and the format of compressed file gzip were standardized with the RFC 1950, RFC 1951 and RFC 1952.

The usual extension of the files “gzippé” is “.gz”. The UNIX software is often distributed with files finished by .tar.gz or .tgz, called Tarball. They are files filed with tar and then compressed with gzip. They can be decompressed with gzip - D file.tar.gz or decompressed and désarchivés with tar xzvf file.tar.gz . Nowadays, more and more of software are distributed to the place in files .tar .bz2 because Bzip2 allows better compression ratios that gzip, and this in spite of a longer time of compression.

AdvanceCOMP implements a compression deflate with the format gzip which provides compression ratios still better than gzip.

Related articles

External bonds

  • Comparative Official site
  • of the performances of various methods of compression of files
  • Page on gnu.org

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