Xz - AbsoluteAstronomy.com

Lossless data compression

Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange...

file format

File format

A file format is a particular way that information is encoded for storage in a computer file.Since a disk drive, or indeed any computer storage, can store only bits, the computer must have some way of converting information to 0s and 1s and vice-versa. There are different kinds of formats for...

incorporating the LZMA2 compression algorithm

Algorithm

In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...

. Like gzip

Gzip

Gzip is any of several software applications used for file compression and decompression. The term usually refers to the GNU Project's implementation, "gzip" standing for GNU zip. It is based on the DEFLATE algorithm, which is a combination of Lempel-Ziv and Huffman coding...

and bzip2

Bzip2

bzip2 is a free and open source implementation of the Burrows–Wheeler algorithm. It is developed and maintained by Julian Seward. Seward made the first public release of bzip2, version 0.15, in July 1996.-Compression efficiency:...

, concatenation

Concatenation

In computer programming, string concatenation is the operation of joining two character strings end-to-end. For example, the strings "snow" and "ball" may be concatenated to give "snowball"...

is supported to compress multiple files, but the convention is to bundle a file that is an archive itself, such as those created by the tar

Tar (file format)

In computing, tar is both a file format and the name of a program used to handle such files...

or cpio

Cpio

cpio is a general file archiver utility and its associated file format. It is primarily installed on Unix-like computer operating systems. The software utility was originally intended as a tape archiving program as part of the Programmer's Workbench , and has been a component of virtually every...

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

programs.

Implementation

An implementation of the xz file format is freely available online under the name XZ Utils. Version 1.22 of GNU tar supports using this software to handle xz files transparently (as it normally does with gzip and bzip2). The implementation as of version 4.999.9beta is licensed under the terms of the GNU LGPL

GNU Lesser General Public License

The GNU Lesser General Public License or LGPL is a free software license published by the Free Software Foundation . It was designed as a compromise between the strong-copyleft GNU General Public License or GPL and permissive licenses such as the BSD licenses and the MIT License...

and GNU GPL

GNU General Public License

The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....

, with the bulk of the software (e.g., liblzma) in the public domain.

7-Zip

7-Zip

7-Zip is an open source file archiver. 7-Zip operates with the 7z archive format, but can read and write several other archive formats. The program can be used from a command line interface, graphical user interface, or with Microsoft Windows shell integration. 7-Zip began in 1999 and is actively...

supports xz as of version 9.04 beta.

Uses

xz is used by the GNU

GNU

GNU is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system"...

coreutils project since version 7.1 to compress its release tarballs. It has gained notability for compressing packages in Fedora

Fedora (operating system)

Fedora is a RPM-based, general purpose collection of software, including an operating system based on the Linux kernel, developed by the community-supported Fedora Project and sponsored by Red Hat...

, Arch Linux

Arch Linux

Arch Linux is an independently developed, Linux-based operating system for i686 and x86-64 computers. It is composed predominantly of free and open source software, and supports community involvement....

, FreeBSD

FreeBSD

FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...

, Slackware

Slackware

Slackware is a free and open source Linux-based operating system. It was one of the earliest operating systems to be built on top of the Linux kernel and is the oldest currently being maintained. Slackware was created by Patrick Volkerding of Slackware Linux, Inc. in 1993...

, CRUX

CRUX

CRUX is a lightweight, i686-optimized GNU/Linux distribution targeted at experienced GNU/Linux users and delivered by a tar.gz-based package system with BSD-style initscripts. It also utilizes a ports system to install and upgrade applications. The current release is 2.7.1.Although crux is the...

, and Funtoo

Funtoo

Funtoo is a a free operating system, more precisely a GNU/Linux distribution based on Gentoo, and initiated in 2008 by Daniel Robbins former Gentoo Linux project leader.- History :...

Implementation

Uses

See also