7-Zip
Top
 |
|
 7-Zip in Windows 7 |
|
| Developer(s) | Igor Pavlov |
|---|---|
| Initial release | 18 July 1999[1] |
| Stable release | 9.20 (18 November 2010)[1] [±] |
| Preview release | 9.26 alpha (31 May 2012)[2] [±] |
| Written in | C++ |
| Operating system | Microsoft Windows, Linux, Mac OS X |
| Available in | 79 languages, including Brazilian Portuguese, Czech, English, French, German, Italian, Japanese, Polish, Russian, Simplified Chinese, Spanish and Korean |
| Type | File archiver |
| License | GNU LGPLv2.1+ with unRAR restriction[3] |
| Website | www.7-zip.org |
7-Zip is a free and 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 a window-based shell integration. 7-Zip began in 1999[1] and is actively developed by Igor Pavlov. The cross-platform version of the command line utility, p7zip, is also available.[4]
7-Zip is free software distributed under the GNU Lesser General Public License (LGPL). It was the winner of the SourceForge.net 2007 community choice awards for "Technical Design" and for "Best Project".[5]
|
Contents
|
Formats
The 7z archive format
Main article: 7z
By default, 7-Zip creates 7z format archives with a .7z file extension. Each archive can contain multiple directories and files. As a container format, security or size reduction are achieved using a stacked combination of filters. These can consist of pre-processors, compression algorithms, and encryption filters.
The core .7z compression uses a variety of algorithms, the most common of which are bzip2, LZMA2, and LZMA. Developed by Igor Pavlov, LZMA is a relatively new system, making its debut as part of the 7z format. LZMA consists of a large LZ-based sliding dictionary up to 4 GB in size, backed by a range coder.[6]
The native 7z file format is open and modular. All filenames are stored as Unicode.[7]
The official 7z file format specification is distributed with the program's source code. The specification can be found in plain text format in the 'doc' subdirectory of the source code distribution.
Other supported formats
7-Zip supports a number of other compression and non-compression archive formats including:
Packing/unpacking of 7z, ZIP, GZip, bzip2, xz, tar, and, since version 9.20, WIM.
Unpacking only: APM, ARJ, CAB, RAR, MSLZ, EXE, SWF, FLV, SquashFS, CramFS, NTFS, FAT, VHD, MBR, Z, LHA, cpio, smzip, JAR, ISO CD/DVD images (7-Zip version 4.42 and up), DMG, HFS, RPM, onepkg and Debian DEB archives.
According to the 7-Zip website, since version 4.65 (from 2009-02-03), 7-Zip can unpack the following formats in addition to the formats it fully supports: ARJ, CAB, CHM, cpio, DEB, DMG, HFS, ISO, LZH, LZMA, MSI, NSIS, RAR, RPM, UDF, WIM, XAR, and Z.
7-Zip is able to open some MSI files, allowing access to the meta-files within along with the main contents. Some Microsoft CAB (LZX compression) and NSIS (LZMA) installer formats can be opened. Similarly, some Microsoft executable programs (.EXEs) which are self-extracting archives or otherwise contain archived content (e.g., some setup files) may be opened as archives.
Since the 7-Zip 9.14 beta, 7-Zip can open and view the content of VHD virtual hard disks.
When compressing ZIP or gzip files, 7-Zip uses its own DEFLATE encoder, which is often able to achieve higher compression levels, but at lower speed, than the more common DEFLATE implementation of zlib. The 7-Zip deflate encoder implementation is available separately as part of the AdvanceCOMP suite of tools.
Variants
Two command line versions are provided: 7z.exe, using external libraries; and a standalone executable 7za.exe containing built-in modules. However, 7za's compression/decompression support is limited to 7z, ZIP, gzip, bzip2, Z and tar formats. A 64-bit version is available, with support for large memory maps leading to faster compression. All versions support multi-threading.
The 7za.exe version of 7-Zip is available for Unix-like operating systems (including Linux, FreeBSD and Mac OS X), FreeDOS, OpenVMS and AmigaOS 4 under the name p7zip. It was developed and is maintained by the developer of 7-Zip for Windows – Igor Pavlov.[4]
Features
7-Zip supports:
- The 256-bit AES cipher. Encryption can be enabled for both files and the 7z directory structure. When the directory structure is encrypted, users are required to supply a password to see the filenames contained within the archive. WinZip-developed zip file AES encryption standard is also available in 7-Zip to encrypt ZIP archives with AES 256-bit, but it does not offer filename encryption as in 7z archives.[8]
- Volumes of dynamically variable sizes, allowing use for backups on removable media such as writable CDs and DVDs.
- Usability as a basic orthodox file manager when used in 2-panel mode.
- Multiple-core CPU threading settings can be configured.
- The ability to attempt to open EXE files as archives, allowing the decompression of data from inside many "Setup" or "Installer" or "Extract" type programs without having to launch them.
- The ability to unpack archives with corrupted filenames, renaming the files as required.
- The ability to create self-extracting single- (but not multi-) volume archives.
- Command-line interface.[9]
Reception
Snapfiles.com gave 7-zip 4.5 stars out of 5, noting that its "interface and additional features are fairly basic, but the compression ratio is outstanding." On Tech Republic, Justin James found the detailed settings for Windows File Manager integration were "appreciated," and called the compression/decompression benchmark utility "neat". And though the comprehensive archive dialog has settings that "will confuse most users,", he concluded, "7-Zip fits a nice niche in between the built-in Windows capabilities and the features of the paid products, and it is able to handle a large variety of file formats in the process."[10] The 2011 review of version 9.20 in PC World magazine pointed out that 7-Zip can "compress and e-mail files in one easy step", and although it offers "options that most users should never have to think about ... The default settings are just fine."[11]
Popularity
7-Zip has been selected for inclusion on the VALO-CD, a collection of open source software for Windows.
See also
References
- ^ a b c "HISTORY of the 7-Zip". www.7-zip.org. 2010-04-15. Archived from the original on 19 April 2010. http://www.7-zip.org/history.txt. Retrieved 2010-04-24.
- ^ a b Pavlov, Igor (2012.02), 7-Zip, http://www.7-zip.org/, retrieved 2012-05-31
- ^ Igor Pavlov (2010). "7-Zip License for use and distribution". 7-zip.org. Archived from the original on 10 April 2010. http://www.7-zip.org/license.txt. Retrieved 2010-04-16.
- ^ a b "P7ZIP". SourceForge.net. February 2009. http://p7zip.sourceforge.net/. Retrieved 2010-04-16.
- ^ "SourceForge.net: 2007 Community Choice Awards". SourceForge.net. 2007. Archived from the original on 26 March 2010. http://sourceforge.net/blog/cca07/. Retrieved 2010-04-16.
- ^ Diaz, Antonio Diaz. "Lzip". lzip.nongnu.org. Archived from the original on 29 July 2010. http://lzip.nongnu.org/lzip.html. Retrieved 29 July 2010.
- ^ 7z format. 7-zip.org.
- ^ "AES Encryption Information: Encryption Specification AE-1 and AE-2". winzip.com. January 30, 2009, WinZip International LLC.
- ^ "Command Line Syntax". sevenzip.sourceforge.jp.
- ^ James, Justin (November 10, 2009). "Review: 7-Zip file compression application". Tech Republic. pp. 1–2. http://www.techrepublic.com/blog/products/review-7-zip-file-compression-application/852.
- ^ Spector, Lincoln (March 15, 2011). "Editorial Review of 7-Zip (32-bit version)". PC World. http://www.pcworld.com/downloads/file/fid,62605-order,4/reviews.html?&page=3.
External links
 |
Wikimedia Commons has media related to: 7-Zip |
- Official website
- 7-Zip on SourceForge.net
- 7-Zip .NET wrapper
- 7-Zip Portable at PortableApps.com
- 7-Zip Theme Manager
|
|||||||||||||||||||||||||||||||||||||||||||||
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Post a question - any question - to the WikiAnswers community:
Copyrights:
Wikipedia on Answers.com
This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article 7-Zip.
Read more