zoo is a data compression

Data compression

In computer science and information theory, data compression, source coding or bit-rate reduction is the process of encoding information using fewer bits than the original representation would use....

 program and format developed by Rahul Dhesi in the mid 1980s. The format is based on the LZW

LZW

Lempel–Ziv–Welch is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch. It was published by Welch in 1984 as an improved implementation of the LZ78 algorithm published by Lempel and Ziv in 1978...

 compression algorithm and compressed files are identified by the .zoo file extension. It is no longer widely used. Program source code was originally published on the comp.sources.misc Usenet

Usenet

Usenet is a worldwide distributed Internet discussion system. It developed from the general purpose UUCP architecture of the same name.Duke University graduate students Tom Truscott and Jim Ellis conceived the idea in 1979 and it was established in 1980...

 newsgroup, and was compatible with a variety of Unix-like

Unix-like

A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....

 operating systems. Binaries were also published for the 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...

 user community. A small companion program was also developed, entitled booz, that provides only decompression functionality.

The .ZOO file format was mostly popular with Digital

Digital Equipment Corporation

Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

 (now Hewlett Packard) VAX

VAX

VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...

 computers running the OpenVMS

OpenVMS

OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...

 operating system, and for a time with the Commodore Amiga

Amiga

The Amiga is a family of personal computers that was sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities...

community.

Zoo features

Zoo archives can store multiple "generations" of a file; if files are added to an archive with the same pathname yet more recent date, if generations are enabled for the archive the older version(s) will be retained (with a semicolon and version number, similar to version numbers in the VMS and RT-11 operating systems) as the new file is added. This allows files that are frequently modified to be backed up in such a way as to allow access to previous versions (up to the version limit chosen) from one archive.

External links

• zoo 2.10 source
• unzoo - zoo archive extractor, source included