(tool, compression)
A program to unpack archives created by PKZIP, written by PKWARE, Inc. and released as shareware. Versions exist for MS-DOS, Microsoft Windows and Open VMS. PKUNZIP is no longer distributed, its functions having been incorporated into PKZIP.
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PK software

A family of compression utilities for DOS, Windows, OS/2, OpenVMS and Unix from PKWARE Inc., Milwaukee, WI ( In 1986, Phil Katz (the PK in PKWARE) developed the ZIP standard that is widely used throughout the world. Originally developed as DOS command line programs, third parties developed graphics-based products that supported the format. Later, PKWARE introduced a Windows version. PKARC and PKXARC were previous compression programs that are no longer supported.

Various Utilities
The PK utilities provide the following functions. PKZIP compresses, and PKUNZIP decompresses. PKSFX and ZIP2EXE create self-extracting archives that automatically decompress when they are run. PKLITE compresses only .EXE and .COM files, which, when run, automatically decompress first. Compression libraries are also available for developers.

In 2001, the ZIP file format was extended to include authentication and encryption features to make ZIP archives secure. Soon after, the company introduced its server-based SecureZIP product family to address the industry-need for not only compression but the secure transfer of data. Another major product was added in 2006; PartnerLink addresses the need to exchange data securely with external business partners.

A Short Career
In 2000, founder Phil Katz, a computer genius who battled many personal problems, died at the young age of 37. He left behind a multimillion-dollar company and one of the most influential pieces of software ever invented for mainstream PC users. See PKZIP abc's, PKZIP cross platform and SecureZIP.

A Zipped Example
The WinZip utility is widely used to compress files using PKZIP. Zipped files are lossless and are restored to their original format bit for bit when decompressed. This example highlights the file size difference. See lossless compression.
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References in periodicals archive ?
Zip-It is more feature-rich than other archiving utilities such as PKZIP and PKUNZIP, the popular shareware programs (available freely on the Web at that are the de facto standard for compressing and extracting files on a PC.
You will need the PKUNZIP.EXE program to unzip the documentation into WordPerfect files.
We are experimenting with using PKZip and PKUnzip (rather than xcopy) to do the transfer, which isn't totally reliable anyhow.
The essential how-to details of Internet procedures (for example, using the PKUNZIP decompression program, and exchanging mail with Bitnet subscribers) are provided; and the major commands available to carry out many of those procedures are listed.
The zipped files can be restored to normal size by executing PKUNZIP on the compacted file.
Individual bulletin boards, where references to PKUNZIP and KERMIT abound, can be intimidating to nongearhead users.
Installation required using the DOS copy command to copy files from two floppy disks to the users hard drive and then decompressing one file using the popular PKZip and PKUnzip programs supplied with the software.
PKZIP and PKUNZIP are probably the most popular set of DOS-based utilities in use today.
Unzip the Mosaic files into a directory of your choice (using PKUNZIP.EXE) and add that directory to your path.
Files with a .ZIP extension require the either PKUNZIP or PCUNZIP for extraction.
WordStar, dBASE IV, PKZIP and PKUNZIP, Geoworks Ensemble, and a host of other programs run flawlessly.
* and the shareware file compression utilities PKZIP, PKUNZIP, and PKLITE from PKWARE, Inc.