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Information about Zoo (file Format)

zoo
File extension:.zoo
Type of format:data compression
zoo is a compression program and format developed by Rahul Dhesi in the mid 1980s. The format is based on the LZW 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 newsgroup, and was compatible with a variety of Unix-like operating systems. Binaries were also published for the MS-DOS 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 (now Hewlett Packard) VAX computers running the OpenVMS operating system.

Technical Specification

A .ZOO archive begins with a 34-byte header field, as follows
Decimal
Offset		 Hex
Offset		 Size
in Bytes		 Description
000-019000-013
20
Archive header text, padded with nulls, terminated by ^Z
020-023014-017
4
Hex string A7DCFDC4
024-027018-01B
4
Offset of first file in archive
028-03101C-019
4
Offset of first file in archive - 1
032020
1
Version of ZOO this Archive was created by
033021
1
Minimum Version of ZOO needed to extract files from archive


Each stored file has its own header, which looks like this
Decimal
Offset		 Hex
Offset		 Size
in Bytes		 Description
000-003000-003
4
Hex string A7DCFDC4
004004
1
Type of directory entry
005005
1
Compression method; 0 - Stored without compression; 1- Crunched (LZW)
006-009006-009
4
Offset of next directory entry
010-01300A-00C
4
Offset of next header
014-01600D-011
2
Original date and time of file
017-018012-013
2
CRC-16 of file
019-022014-017
4
Uncompressed file size
023-026018-01B
4
Compressed file size
02701C
1
Version of ZOO by which this file was compressed
02801D
1
Minimum version of ZOO needed to extract this file
02901E
1
Deleted flag: 0-File is present; 1-file is marked as deleted
03001F-022
4
Offset to file comment field or 0 if no comment
031-032023-024
2
Length of comment field
033+025+VariableFile name, which may include a path, null terminated

Other uses

The file format .zoo are also saved zoos for Microsoft's Zoo Tycoon PC game.

External links

A filename extension is a suffix to the name of a computer file applied to indicate its type. It is commonly used to infer information about what sort of data might be stored in the file.
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data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an un-encoded representation would use through use of specific encoding schemes.
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data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an un-encoded representation would use through use of specific encoding schemes.
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Lempel-Ziv-Welch (LZW) 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.
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Usenet (USEr NETwork) is a global, decentralized, distributed Internet discussion system that evolved from a general purpose UUCP architecture of the same name. It was conceived by Duke University graduate students Tom Truscott and Jim Ellis in 1979.
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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.
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MS-DOS (short for Microsoft Disk Operating System) is an operating system commercialized by Microsoft. It was the most commonly used member of the DOS family of operating systems and was the dominant operating system for the PC compatible
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Digital Equipment Corporation was a pioneering American company in the computer industry. It is often referred to within the computing industry as DEC. (This acronym was frequently officially used by Digital itself,[1] but the official name was always DIGITAL.
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Hewlett-Packard Co.

Public (NYSE:  HPQ )
Founded Palo Alto, California (1939)
Headquarters Palo Alto, California, USA

Key people Bill Hewlett, Co-founder
David Packard, Co-founder
Mark V.
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VAX is a 32-bit computing architecture that supports an orthogonal instruction set (machine language) and virtual addressing (i.e. demand paged virtual memory). It was developed in the mid-1970s by Digital Equipment Corporation (DEC).
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OpenVMS[1] (Open Virtual Memory System or just VMS) is the name of a high-end computer server operating system that runs on the VAX[2] and Alpha[3]
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A zoological garden, zoological park, or zoo is a facility in which animals are confined within enclosures and displayed to the public, and in which they may also be bred.
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Microsoft Corporation

Public (NASDAQ:  MSFT )
Founded Albuquerque, New Mexico, USA (April 4 1975)[1]
Headquarters Redmond, Washington, United States

Key people Bill Gates, Co-founder and Executive Chairman ;
Paul Allen, Co-founder ;
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Zoo Tycoon is a simulation computer game developed by Blue Fang Games and released by Microsoft Game Studios. It is a Tycoon game, in which the player must run a business, in this case a zoo, and try to make a profit.
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