Info-ZIP
Encyclopedia
Info-ZIP is a set of open-source software
to handle ZIP archives
. It has been in circulation since 1989. It consists of 4 separately-installable packages: the Zip and UnZip command-line utilities; and WiZ and MacZip, which are graphical user interface
s for archiving programs in Microsoft Windows
and classic MacOS, respectively.
Info-ZIP's Zip and UnZip have been ported to dozens of computing platforms. The UnZip web page describes UnZip as "The Third Most Portable Program in the World", surpassed by Hello World, C-Kermit, and possibly the Linux kernel
. The "zip" and "unzip" programs included with most Linux and Unix distributions are Info-ZIP's Zip and UnZip.
In addition to the Info-ZIP releases themselves, parts of Info-ZIP, including zlib
, have been used in numerous other file archiver
s and other programs. Many Info-ZIP programmers have also been involved in other projects closely related to the DEFLATE
compression algorithm, such as the PNG image format and the zlib
software library.
The Zip package includes three additional utilities:
and C
versions. Pascal was abandoned soon after. Smith's UnZip 2.0, in September, included support for the "unimploding" (method 6) as in PKZIP
1.01. Carl Mascott and John Cowan released UnZip 2.0a in December.
In Spring 1990, Info-ZIP was formed as a mailing list
on SIMTEL20, and released UnZip 3.0. In December, UnZip 4.0, with ZIP file "central directory" support, was released.
UnZip 5.0 and Zip 1.9 were released in August 1992; these are the first Info-ZIP programs to support the new DEFLATE
(method 8) compression method used in PKZIP
1.93a. Method 8 has become the de facto base standard for ZIP archives.
In 1994 and 1995 Info-ZIP turned a corner, and effectively became the de facto ZIP program on non-MS-DOS
systems. A huge number of ports were released that year, including numerous minicomputer
s, mainframes
and practically every microcomputer
ever developed.
WiZ 4.0 was released in November 1997.
The first times Info-ZIP released versions under the new BSD-like Info-ZIP License were Zip 2.3 in December 1999 and UnZip 5.41 and WiZ 5.01 in April 2000.
The first MacZip (1.05) was released in July 2000; the last version was 1.06, released in February 2001. It was written by Dick Hasse.
General Deflate64 (method 9) decompression was introduced with UnZip 5.50, whose main release was in February 2002.
UnZip 6.0 includes "Zip64" large file support and bzip2-method (method 12) decompression. Support for bzip2-style compression was also in Zip from 3.0f beta.
Open-source software
Open-source software is computer software that is available in source code form: the source code and certain other rights normally reserved for copyright holders are provided under a software license that permits users to study, change, improve and at times also to distribute the software.Open...
to handle ZIP archives
ZIP (file format)
Zip is a file format used for data compression and archiving. A zip file contains one or more files that have been compressed, to reduce file size, or stored as is...
. It has been in circulation since 1989. It consists of 4 separately-installable packages: the Zip and UnZip command-line utilities; and WiZ and MacZip, which are graphical user interface
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...
s for archiving programs in Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
and classic MacOS, respectively.
Info-ZIP's Zip and UnZip have been ported to dozens of computing platforms. The UnZip web page describes UnZip as "The Third Most Portable Program in the World", surpassed by Hello World, C-Kermit, and possibly the Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
. The "zip" and "unzip" programs included with most Linux and Unix distributions are Info-ZIP's Zip and UnZip.
In addition to the Info-ZIP releases themselves, parts of Info-ZIP, including zlib
Zlib
zlib is a software library used for data compression. zlib was written by Jean-Loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. Zlib is also a crucial component of many software platforms including Linux, Mac OS X,...
, have been used in numerous other file archiver
File archiver
A file archiver is a computer program that combines a number of files together into one archive file, or a series of archive files, for easier transportation or storage...
s and other programs. Many Info-ZIP programmers have also been involved in other projects closely related to the DEFLATE
DEFLATE
Deflate is a lossless data compression algorithm that uses a combination of the LZ77 algorithm and Huffman coding. It was originally defined by Phil Katz for version 2 of his PKZIP archiving tool and was later specified in RFC 1951....
compression algorithm, such as the PNG image format and the zlib
Zlib
zlib is a software library used for data compression. zlib was written by Jean-Loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. Zlib is also a crucial component of many software platforms including Linux, Mac OS X,...
software library.
Features
The UnZip package also includes three additional utilities:- fUnZip extracts a file in a ZIP or gzipGzipGzip 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...
file directly to output from archives or other piped input. - UnZipSFX is software to make a ZIP file into an executable self-extracting archiveSelf-extracting archiveA self-extracting archive is a computer application which contains a file archive, as well as programming to extract this information. Such file archives do not require a second executable file or program to extract from the archive, as archive files usually require...
. - ZipInfo outputs, in a variety of formats, information about ZIP files and their contents.
The Zip package includes three additional utilities:
- ZipCloak adds or removes password encryption from file in a ZIP archive.
- ZipNote allows the modification of comment fields in ZIP archives.
- ZipSplit splits a ZIP archive into sections for separate disks or downloads.
History
The first version of UnZip was released by Samuel M. Smith in March 1989, with PascalPascal (programming language)
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object Pascal...
and C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
versions. Pascal was abandoned soon after. Smith's UnZip 2.0, in September, included support for the "unimploding" (method 6) as in PKZIP
PKZIP
PKZIP is an archiving tool originally written by Phil Katz and marketed by his company PKWARE, Inc. The common "PK" prefix used in both PKZIP and PKWARE stands for "Phil Katz".-History:...
1.01. Carl Mascott and John Cowan released UnZip 2.0a in December.
In Spring 1990, Info-ZIP was formed as a mailing list
Mailing list
A mailing list is a collection of names and addresses used by an individual or an organization to send material to multiple recipients. The term is often extended to include the people subscribed to such a list, so the group of subscribers is referred to as "the mailing list", or simply "the...
on SIMTEL20, and released UnZip 3.0. In December, UnZip 4.0, with ZIP file "central directory" support, was released.
UnZip 5.0 and Zip 1.9 were released in August 1992; these are the first Info-ZIP programs to support the new DEFLATE
DEFLATE
Deflate is a lossless data compression algorithm that uses a combination of the LZ77 algorithm and Huffman coding. It was originally defined by Phil Katz for version 2 of his PKZIP archiving tool and was later specified in RFC 1951....
(method 8) compression method used in PKZIP
PKZIP
PKZIP is an archiving tool originally written by Phil Katz and marketed by his company PKWARE, Inc. The common "PK" prefix used in both PKZIP and PKWARE stands for "Phil Katz".-History:...
1.93a. Method 8 has become the de facto base standard for ZIP archives.
In 1994 and 1995 Info-ZIP turned a corner, and effectively became the de facto ZIP program on non-MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
systems. A huge number of ports were released that year, including numerous minicomputer
Minicomputer
A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...
s, mainframes
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
and practically every microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...
ever developed.
WiZ 4.0 was released in November 1997.
The first times Info-ZIP released versions under the new BSD-like Info-ZIP License were Zip 2.3 in December 1999 and UnZip 5.41 and WiZ 5.01 in April 2000.
The first MacZip (1.05) was released in July 2000; the last version was 1.06, released in February 2001. It was written by Dick Hasse.
General Deflate64 (method 9) decompression was introduced with UnZip 5.50, whose main release was in February 2002.
UnZip 6.0 includes "Zip64" large file support and bzip2-method (method 12) decompression. Support for bzip2-style compression was also in Zip from 3.0f beta.
External links
- Info-ZIP Home Page — official site