Archive format
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Archive_format".

An archive format is the file format of an archive file. The archive format is determined by the file archiver. Some archive formats are well-defined by their authors and have become conventions supported by multiple vendors and/or open-source communities.

Archive formats support features such as file concatenation, compression, encryption, file spanning, parity/Cyclic redundancy check, checksum, self-extraction, self-installation, volume and directory structure information, package notes/description, and other meta-data.

Types of Archive Formats

• Archiving only formats only concatenate files.
• Compression only formats only compress files.
• Multi-function formats can concatenate, compress, encrypt, create error detection and recovery information, and repackage the archive into self-extracting/self-expanding files.
• Software Packaging formats are used to create software packages that may be self-installing files.
• Disk Image formats are used to create disk images or optical disk images of mass storage volumes.

Examples

Note: a comprehensive List of archive formats and Comparison of archive formats is available.

By Type

By Operating System

Unix operating systems utilize the tar file format, ar, and shar To concatenate files. These archive formats can then be compressed into gzip format.

On Windows platforms, the most widely-used archive format is ZIP; other formats are CAB, RAR (file format), and ACE. Windows Installer is a high-level archive format for distribution of software.

On Amiga computers the standard archive format is LHA.

on Apple Macintosh computers StuffIt is among the most common, with Zip also supported natively in recent Mac OS X (10.3+).

Linux often uses TAR, gz, RAR (file format), and RPM package manager, a Package management system for distribution of software.

History

Origins

Ubiquitous amongst Unix and Unix-like operating systems is the tar file format ("tape archive"). Originally intended for transferring files to and from tape, it is still used on disk-based storage to combine files before they are compressed.

Development

Historically, every major computer platform, every operating system, and every vendor had its own preferred archive format. Some formats became more commonly used because of licensing, feasibility, and popularity. Today the most common formats are supported by many platforms and vendors. New technologies continue to introduce new formats.

See also

• List of archive formats
• Comparison of archive formats
• File archiver
• Archive file
• Container format (digital), a similar concept in media files

References

• "Application Note on the .ZIP file format"- official white paper published by PKWARE, Inc.
• Tape Archive (.TAR) file format specification- excerpt from File Format List 2.0 by Max Maischein
• "IBM 726 Magnetic tape reader/recorder from IBM Archives
• "1401 Data Processing System" from IBM Archives

External links

• Archive formats at the Open Directory Project