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GZIP/GZ standing for GNU zip. It is based
on the DEFLATE algorithm, which is a combination of Lempel-Ziv (LZ77) and Huffman
coding. The program was created by Jean-Loup Gailly and Mark Adler as a free software
replacement for the compress program used in early Unix systems, and intended
for use by the Project. Its main advantages over compress are much better compression
and freedom from patented algorithms. It has been adopted by the GNU project and
is now relatively popular on the Internet. Version 0.1 was first publicly released
on October 30, 1992, and version 1.0 followed in February 1993.
The format was designed to allow single pass compression without any backwards
seek, and without a priori knowledge of the uncompressed input size or the available
size on the output media. If input does not come from a regular disk file, the
file modification time is set to the time at which compression started.
The gzip format allows multiple compression methods (although gzip currently
supports only the 'deflate' method). It must be possible to detect the end of
the compressed data with any compression method, regardless of the actual size
of the compressed data. In particular, the decompressor must be able to detect
and skip extra data appended to a valid compressed file on a record-oriented file
system, or when the compressed data can only be read from a device in multiples
of a certain block size. (This condition is not fulfilled by the 'compress' program,
which has no way of determining the end of compressed data from the data itself.)
Gzip is based on the DEFLATE algorithm, which is a combination of LZ77 and
Huffman coding. DEFLATE was intended as a replacement for LZW and other patent-encumbered
data compression algorithms, which, at the time, limited the usability of compress
and other popular archivers.
"Gzip" is often also used to refer to the gzip file format, which
is:
- a 10-byte header, containing a magic number, a version number and a time
stamp
- optional extra headers, such as the original file name
- a body, containing a DEFLATE-compressed payload
- an 8-byte footer, containing a CRC-32 checksum and the length of the original
uncompressed data
In general, gzip file ends with a .gz extension.
To extract/unzip.uncompress/open gzip/gz files, we recommend you a popular
and 100% free software - 7-Zip. 7-Zip is an open
source freeware. You can use 7-Zip on any computer, including a computer
in a commercial organization. You don't need to register or pay for 7-Zip.
To associate gz/gzip file to 7-Zip in Windows, please click menu "Tools"
-> "Options" -> "System", and then check
"gz" and "gzip", and then click OK.
If you're using Windows 7 or Vista, you must run 7-Zip in administrator mode.
Please right-click the icon of 7-Zip File Manager, and then click Run as administrator.
In File Explorer, you could right-click on gz/gzip file and choose "7-Zip"
-> "Open archive" or "Extract files" to open/extract
gz/gzip file.
7-Zip freeware works in Windows 10 / 8 / 7 / Vista / XP / 2008 / 2003 / 2000
/ NT / ME / 98.
The 7-Zip is absolutely virus, spyware, marlware,
and adware free. It's safe to install.
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