PKZIP

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PKZIP is a file filing computer program, famous for introducing popular ZIP file formats. PKZIP was first introduced to MS-DOS on IBM-PC compatible platforms in 1989. Since then, the versions have been released for a number of other architectures and operating systems. PKZIP was originally written by Phil Katz and marketed by his company, PKWARE, Inc., with both having initials: 'PK'.

Video PKZIP

Histori

In the 1970s, file archiving programs were distributed as standard utilities with the operating system. They include Unix utilities ar, shar, and tar. This utility is designed to collect a number of separate files into one archive file for easy copying and distribution. These archives can be optionally passed through the flow compressor utility, such as compress and others.

Other archivists also appeared during the 1980s, including ARC by System Enhancement Associates, Inc. (SEA), ZOO Rahul Dhesi, DWC Dean W. Cooper, LHarc by Haruhiko Okomura and Haruyasu Yoshizaki and ARJ which stands for "Archived by Robert Jung".

PKZIP development was first announced in the SOFTDEV.DOC file from within the PKPAK 3.61 package, stating it will develop a new and unnamed compression program. The announcement was made following a lawsuit between SEA and PKWARE, Inc. Although the SEA won the suit, it lost the compression war, because the user base migrated to PKZIP as the preferred compressor. Led by BBS sysops refusing to accept or offer compressed files as.ARC files, users start compressing old archives that are currently stored in.ARC format into.ZIP files.

To help ensure interoperability of the ZIP format, Phil Katz publishes the original ZIP File Specification in the APPNOTE.TXT documentation file. PKWARE continues to maintain this document and updates are published periodically. Originally bundled with a PKZIP registered version, it was then available on the PKWARE website.

The specification has its own version number, which does not always match the PKZIP version number, especially with PKZIP 6 or later. On various occasions, PKWARE adds an initial feature that allows PKZIP products to extract archives using advanced features, but PKZIP products that keep those archives will not be available until the next big release.

Maps PKZIP

Compatibility

Although popular at the time, the ZIP archive using the PKZIP 1.0 compression method is now scarce, and many modern unzip tools can not handle "shrink" and "subtract", although "explode" is usually supported.

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Patent

Shrinking uses dynamic LZW, where Unisys holds patents. Patents for the Reducing Algorithm have also been filed on June 19, 1984, long before PKZIP was produced.

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Other products

PKWARE also uses the PKZIP standard for the following products:

• SecureZIP (including SecureZIP PartnerLink)
• PKZIP Explorer

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See also

• Comparison of file archiving
• Comparison of archive formats
• List of archive formats

src: alternative101.com

References

src: www.alleycatsw.com

External links

Official

• Official website , PKWARE
• PKZIP from PKWARE
• PKZIP 2.50 for DOS
• SecureZIP from PKWARE
• APPNOTE

More

• SecureZIP home page
• Comments from SEA owners about Phil Katz, his suit, and death
• CONTROVERSION: LAW: SEA vs PKWARE
  • Judgment in favor of SEA at SEA v. PKWARE and Phil Katz
• How to Use PKZIP From the Command Line

Source of the article : Wikipedia