Archive file
Encyclopedia
An archive file is a file that is composed of one or more files along with metadata
that can include source volume and medium information, file directory structure, error detection and recovery information, file comments, and usually employs some form of lossless compression. Archive files may be encrypted
in part or as a whole. Archive files are used to collect multiple data files together into a single file for easier portability and storage, or simply to compress files to use less storage space.
Computer archive files are created by file archiver
software, optical disc authoring software, or disk image
software that uses an archive format
determined by that software. The file extension or file header of the archive file are indicators of the file format used.
Archive files are sometimes accompanied by separate parity archive (PAR) files that allow for additional error detection and recovery, particularly in recovery of missing files in a multi-file archive.
In operating systems that distinguish different file types by filename extension
s, archive extensions include .zip
, .rar, .7z
, and .tar
, (of these examples, .tar is the only non-compressed format). Java also introduced a whole family of archive extensions such as .jar
and .war
('j' is was Java and 'w' is for web). They are used to exchange entire byte-code deployment. Sometimes they are also used to exchange source codes and other text/html/xml files. By default they are all compressed.
Metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
that can include source volume and medium information, file directory structure, error detection and recovery information, file comments, and usually employs some form of lossless compression. Archive files may be encrypted
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
in part or as a whole. Archive files are used to collect multiple data files together into a single file for easier portability and storage, or simply to compress files to use less storage space.
Computer archive files are created by file archiver
File archiver
A file archiver is a computer program that combines a number of files together into one archive file, or a series of archive files, for easier transportation or storage...
software, optical disc authoring software, or disk image
Disk image
A disk image is a single file or storage device containing the complete contents and structure representing a data storage medium or device, such as a hard drive, tape drive, floppy disk, CD/DVD/BD, or USB flash drive, although an image of an optical disc may be referred to as an optical disc image...
software that uses an archive format
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....
determined by that software. The file extension or file header of the archive file are indicators of the file format used.
Archive files are sometimes accompanied by separate parity archive (PAR) files that allow for additional error detection and recovery, particularly in recovery of missing files in a multi-file archive.
In operating systems that distinguish different file types by filename extension
Filename extension
A filename extension is a suffix to the name of a computer file applied to indicate the encoding of its contents or usage....
s, archive extensions include .zip
ZIP (file format)
Zip is a file format used for data compression and archiving. A zip file contains one or more files that have been compressed, to reduce file size, or stored as is...
, .rar, .7z
7z
7z is a compressed archive file format that supports several different data compression, encryption and pre-processing algorithms. The 7z format initially appeared as implemented by the 7-Zip archiver. The 7-Zip program is publicly available under the terms of the GNU Lesser General Public...
, and .tar
Tar (file format)
In computing, tar is both a file format and the name of a program used to handle such files...
, (of these examples, .tar is the only non-compressed format). Java also introduced a whole family of archive extensions such as .jar
JAR (file format)
In software, JAR is an archive file format typically used to aggregate many Java class files and associated metadata and resources into one file to distribute application software or libraries on the Java platform.JAR files are built on the ZIP file format and have the .jar file extension...
and .war
WAR (file format)
In computing, a WAR file is a JAR file used to distribute a collection of JavaServer Pages, Java Servlets, Java classes, XML files, tag libraries and static Web pages that together constitute a Web application.-Content and structure:A WAR file may be digitally signed in the same way as a JAR file...
('j' is was Java and 'w' is for web). They are used to exchange entire byte-code deployment. Sometimes they are also used to exchange source codes and other text/html/xml files. By default they are all compressed.
History
Archive files were originally used to store important files on alternate media, such as tapes, for preservation and recoverability. Archive files are now commonly used for transferring files and for software distribution & installation.See also
- File archiverFile archiverA file archiver is a computer program that combines a number of files together into one archive file, or a series of archive files, for easier transportation or storage...
- Archive formatArchive formatAn 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....
- Disk imageDisk imageA disk image is a single file or storage device containing the complete contents and structure representing a data storage medium or device, such as a hard drive, tape drive, floppy disk, CD/DVD/BD, or USB flash drive, although an image of an optical disc may be referred to as an optical disc image...
- Optical disc image