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7-Zip is a data compression and file-archiving program predominantly for the Microsoft Windows operating system. It operates either as a command line program or with a graphical user interface. It also features integration with the Windows shell environment. 7-Zip is free software, distributed under the GNU LGPL license. Several attempts over the last 2 years have been made to port this onto Linux and a one such example is p7zip (found on SourceForge). The spring 2005 release of KDE will officially be the first Unix desktop environment to support 7-Zip. It is a competitor to the market-leading WinZip and WinRAR programs, both of which are closed source.
7-Zip introduced the flexible 7z file format, but it also supports a number of other compressed and uncompressed archive file formats, including ZIP, Microsoft cabinet (CAB) files, RAR, ARJ, Gzip, Bzip2, TAR, CPIO, RPM, and Debian deb archives. 7-Zip is also able to create self-extracting archive files when used with the 7z format.
For ZIP and Gzip files, 7-Zip uses a modified implementation of the DEFLATE algorithm that is tuned for higher compression levels at the expense of speed. This implementation is also used in the AdvanceCOMP tools.
For 7z format files, 7-Zip also supports 256-bit AES encryption of both files and the 7z directory structure, preventing users without the password from even seeing the archive contents. The native 7z file format is an open, modular architecture which allows it to contain files compressed using different algorithms. Filenames are stored as unicode.
By default, the program creates files in the 7z archive format (with the file extension .7z) using the LZMA algorithm for compression. These defaults allow the program to achieve the highest compression ratio compared to other popular high compression formats such as ACE and RAR which are based on older, proprietary algorithms. Such files have the MIME-type application/x-7z-compressed.
See also: ZIP, CAB, LHA, DGCA, GCA, RAR archive formats, AdvanceCOMP
External links
- 7-Zip Official Website (http://www.7-zip.org/)
- A quick port of 7z.exe and 7za.exe (command line version of 7zip) for Unix (http://p7zip.sourceforge.net/)
- Resolved KDE 7-Zip issues (http://bugs.kde.org/show_bug.cgi?id=48267). Previously reasons for not including support within the KDE ARK package.
- PowerArchiver (http://powerarchiver.com), a shareware compression utility for Windows, uses the 7-Zip format as its default compression format starting from version 9.0. It is most likely the first non-free software to support 7-Zip, along with bzip2 and GNU ZIP compression, both plain and tarballed. PowerArchiver's spread is hampered by the market dominance and brand recognition of WinZip among Windows users. Some people consider this unfortunate as PowerArchiver's spread would increase the exposure of Free/Open Source Software technologies to the Windows desktop.
- Servant Salamander (http://www.altap.cz) is a Windows file manager which supports 7-Zip format, along with many other archive formats. It supports comfortable listing, extraction and creation of archives both using keyboard and drag&drop.
- TugZip (http://www.tugzip.com) is freeware since version 1.1 (Aug/02) and supports 7-ZIP along with zip, rar, ace, arc, arj, bh, bz2, cab, cpio, deb, gca, gz, imp, jar, lha, lzh, lib, rpm, sqx, tar, tgz, tbz, taz, yz1 and zoo archives. Version 3.2 can open BIN, C2D, IMG, ISO and NRG images and can repair corrupt zip archives. TugZip makes 7-zip SFX (self extract archives), has encryption, web-updates, drag & drop, command scripting, spanning, shell support, and has add-on's for 20-languages.
- IZarc (http://www.izsoft.dir.bg/izarc.htm) is freeware (since 2003) and supports 7-ZIP, a, ace, arc, arj, b64, bh, bz2, bza, cab, cpio, deb, enc, gca, gz, gza, ha, jar, lha, lzh, lib, mbf, mim, pak, pk3, rar, prm, tar, taz, tbz, tgz, tz, uue, war, xxe, yz1, z, zip, and zoo. Like Winzip, RAR, and TugZip, IZarc also has basic right-click shell support. Version 2 was released Aug/04 and progress still continues with Version 3.5b in Jan/05.
- Inno Setup (http://www.jrsoftware.org/isinfo.php) is one of the most popular Windows auto installers in use by developers. It has built-in 7-zip compression making single-file software install packages as small as possible.
- NSIS (http://nsis.sourceforge.net/features) is another popular Windows auto installer, also sporting 7-zip compression. As a free SourceForge project like 7-zip, many developers have provided input to help fine-tune its abilities (eg: WinAmp.com).
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