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[[Image:InfoZIP.png|right|250px]]
[[Image:InfoZIP.png|right|250px]]
An [[open source]] project that started in 1990 to create a portable compression/de-compression program that is compatible with [[PKWare]]'s [[PKZip]] program, it was originally based on the Unzip [[DOS]] program that Samuel H. Smith had created a year earlier but due to licensing restrictions it was soon completely rewritten. Info-Zip consists of two command line application programs ''Zip'' and '''Unzip'' that handle compression and decompression respectively, although the Zip program can decompress as well as compress, in addition the suite contains a few related utility programs some of them included in the main package and some available as a separate download.
An [[open source]] project that started in 1990 to create portable compressor-archiver utilities that are compatible with PKWare's [[PKZIP]] file format.


The Info-Zip code has a fairly liberal [[Info-Zip Licence|licence]] which meant code from the project was routinely used in projects that required file compression, archival capabilities or compatibility with the [[ZIP]] file format, however in modern use it is more common to use compression libraries such as the Info-ZIP derivative [[Zlib]] unless the archival features of Info-ZIP are required, since the libraries are more flexible and give much better compression ratios.
==History==
Info-ZIP developed two command line application programs ''Zip'' and ''Unzip'' that handle compression and decompression respectively. Although the Zip program can decompress as well as compress, in addition there are a few related utility programs some of them included in the main package and some available as a separate download.
 
The Info-Zip code has a fairly liberal [[Info-Zip Licence|licence]] which meant code from the project was routinely used in projects that required file compression, archival capabilities or compatibility with the ZIP file format. However in modern use it is more common to use compression libraries such as the Info-ZIP derivative Zlib unless the archival features of Info-ZIP are required, since the libraries are more flexible and give much better compression ratios.


However apart from the utility you get from the Info-ZIP Zip and Unzip programs themselves there are cases where it makes sense to use Info-Zip code in your project rather than a library or even use applications themselves and make them a dependency of your program. Some software such as [[Java]] Jars implementation understands the ZIP file format to be strictly ISO/IEC 21320-1:2015 compatible, i.e. they only allow Deflate 0 and 8 and require the file structure to be compatible with the Info-ZIP one, in those cases the more modern compression libraries have no advantage since the better compression ratios are not understood or even allowed by the ISO 21320-1 and similarly with a library you will need to write your own file structure code but all that is already built into Info-ZIP.
However apart from the utility you get from the Info-ZIP Zip and Unzip programs themselves there are cases where it makes sense to use Info-Zip code in your project rather than a library or even use applications themselves and make them a dependency of your program. Some software such as [[Java]] Jars implementation understands the ZIP file format to be strictly ISO/IEC 21320-1:2015 compatible, i.e. they only allow Deflate 0 and 8 and require the file structure to be compatible with the Info-ZIP one, in those cases the more modern compression libraries have no advantage since the better compression ratios are not understood or even allowed by the ISO 21320-1 and similarly with a library you will need to write your own file structure code but all that is already built into Info-ZIP.


On OS/2 you can also get Info-ZIP in the form of a [[REXX]] compatible [[dynamic link library]] which makes coding using it even simpler as long as your language has REXX DLL compatibility as in the case of [[PERL]] or if you write a simple DLL wrapper in your code.
The project ran into a number of problems during its early years. Some of the core programmers wanted to extend the capabilities of the package over and above what PKZIP had to offer and align with the [[Free Software Foundation]] by releasing under the [[GPL]]. However both of these proposals were rejected by the rest of the community due to compatibility reasons and the restrictions of the GPL. This eventually lead a number of core team members to start a new project called ''gzip'' that was part of the FSF GNU project, although later projects by the same team have eschewed the FSF and been released under a more liberal licence.
 
==Background and history==
When ZIP took over as most popular compression format on PC's almost overnight in 1989 it created a problem for end users of other computer systems and network operators as unlike the [[ARC]] format that had a copyrighted but open source made available for the express purpose of creating unarchivers for other operating systems, the ZIP format did not and was only available as an executable for [[DOS]] based machines. This meant that end users that were accustomed to downloading PC archive files from [[BBS]]'s and file archives on the internet suddenly found they could not decompress those files but prior to that you could download an ARC file and have an ARC decompressor for your system. Similarly system administrators found themselves in a pickle as that there were almost no PC based servers that used DOS as the operating system, most servers in use used either [[Novell Netware]] or a [[UNIX]] derived system, and admins were suddenly flooded with ZIp files that they could not examine unless they had an access to a DOS machine.
 
==Known derivatives==
Mark Adler and Jean-loup Gailly who were that main authors of the Zip and Unzip programs left the project fairly early on after some disagreements and started the GZip project that was originally based on Info-Zip Code and also later founded the PNG and library versions below:
* [[Gzip]]
* [[Libpng]]
* [[PNG]]
* [[Zlib]]
 
==Links & publications==
* [http://www.info-zip.org Info-Zip project homepage]
* [http://www.info-zip.org/mans/ Info-Zip technical information]
 
====Articles====
* [[Richard K. Goran]]: [[Info-ZIP's UnZip REXX Interface]]


==Licence==
==Software==
Open source software, current versions were published under the [[Info-Zip Licence]], prior to the release of version 2.3 the project used an ad hoc licence buried inside different parts the readme file.
*[[Info-ZIP UnZip|UnZip]] 6.0 (2009-04-29)
*[[Info-ZIP Zip|Zip]] 3.00 (2008-07-07)
*WiZ 5.03 (2005-03-11)
*MacZip 1.06 (2001-02-22)


==Authors==
==Links==
<div style="column-count:3;-moz-column-count:3;-webkit-column-count:3">
* [http://www.info-zip.org Info-ZIP Home Page]
* Mark Adler (original Zip author)
* [http://www.info-zip.org/mans/ Info-ZIP technical information]
* John Bush
* [http://www.info-zip.org/phpBB3/index.php Info-ZIP forum]
* Karl Davis
* [http://www.quicktopic.com/27/H/V6ZQZ54uKNL Archive of the old Info-ZIP forum]
* Harald Denker
* Jean-Michel Dubois
* Jean-loup Gailly
* Hunter Goatley
* Ed Gordon
* Ian Gorman
* Chris Herborth
* Dirk Haase
* Greg Hartwig
* Robert Heath
* Jonathan Hudson
* Paul Kienitz
* David Kirschbaum
* Johnny Lee
* Onno van der Linden
* Igor Mandrichenko
* Steve P. Miller
* Sergio Monesi
* Keith Owens
* George Petrov
* Greg Roelofs
* [[Kai-Uwe Rommel]] (OS/2 specific code)
* Steve Salisbury
* Dave Smith
* Steven M. Schweda
* Christian Spieler
* Cosmin Truta
* Antoine Verheijen
* Paul von Behren
* Rich Wales
* Mike White.
</div>


[[Category:Compression]]
[[Category:Open Source Software]]
[[Category:Compression utilities]]

Latest revision as of 13:58, 9 January 2023

An open source project that started in 1990 to create portable compressor-archiver utilities that are compatible with PKWare's PKZIP file format.

History

Info-ZIP developed two command line application programs Zip and Unzip that handle compression and decompression respectively. Although the Zip program can decompress as well as compress, in addition there are a few related utility programs some of them included in the main package and some available as a separate download.

The Info-Zip code has a fairly liberal licence which meant code from the project was routinely used in projects that required file compression, archival capabilities or compatibility with the ZIP file format. However in modern use it is more common to use compression libraries such as the Info-ZIP derivative Zlib unless the archival features of Info-ZIP are required, since the libraries are more flexible and give much better compression ratios.

However apart from the utility you get from the Info-ZIP Zip and Unzip programs themselves there are cases where it makes sense to use Info-Zip code in your project rather than a library or even use applications themselves and make them a dependency of your program. Some software such as Java Jars implementation understands the ZIP file format to be strictly ISO/IEC 21320-1:2015 compatible, i.e. they only allow Deflate 0 and 8 and require the file structure to be compatible with the Info-ZIP one, in those cases the more modern compression libraries have no advantage since the better compression ratios are not understood or even allowed by the ISO 21320-1 and similarly with a library you will need to write your own file structure code but all that is already built into Info-ZIP.

The project ran into a number of problems during its early years. Some of the core programmers wanted to extend the capabilities of the package over and above what PKZIP had to offer and align with the Free Software Foundation by releasing under the GPL. However both of these proposals were rejected by the rest of the community due to compatibility reasons and the restrictions of the GPL. This eventually lead a number of core team members to start a new project called gzip that was part of the FSF GNU project, although later projects by the same team have eschewed the FSF and been released under a more liberal licence.

Software

  • UnZip 6.0 (2009-04-29)
  • Zip 3.00 (2008-07-07)
  • WiZ 5.03 (2005-03-11)
  • MacZip 1.06 (2001-02-22)

Links