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Archive file

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In computing, an archive file stores the content of one or more files, possibly compressed, with associated metadata such as file name, directory structure, error detection and correction information, comments, and sometimes encryption. An archive file is often used to facilitate portability, distribution and backup, and to reduce storage use.[1][2][3]

Applications

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Portability

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As an archive file stores file system information, including file content and metadata, it can be leveraged for file system content portability across heterogeneous systems. For example, a directory tree can be sent via email, files with unsupported names on the target system can be renamed during extraction, timestamps can be retained rather than lost during data transmission.[4] Also, transfer of a single archive file may be faster than processing multiple files due to per-file overhead,[5][6] and even faster if compressed.

Software distribution

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Beyond archiving, archive files are often used for software distribution. When used in connection with a package manager, an archive must conform to a package format and is called a package. In particular, the format usually requires a manifest file.[7] Examples include deb for Debian, JAR for Java, APK for Android, and self-extracting Windows Installer executables.

Features

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Notable features supported for various archives include:

Error detection and recovery

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Archive files often include parity checks and other checksums for error detection, for instance zip files use a cyclic redundancy check (CRC). RAR archives may include additional error correction data (called recovery records).[8]

Archive files that do not natively support recovery records can use separate parchive (PAR) files that allows for additional error correction and recovery of missing files in a multi-file archive.[9]

Format

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The format of an archive file is its archive format. Some formats are well-defined and some have become conventions supported by multiple vendors and communities.[10] As is common for all files, the format of an archive is generally indicated by file name extension and/or file header.[11]

Commonly used formats include zip, rar, 7z, and tar.[12] Java introduced archive formats including jar (j for Java) and war (w for web) that store an entire runnable deployment; usually compressed.[13]

See also

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References

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  1. ^ "Archive File: What it's Used For". Lifewire. Archived from the original on 2024-07-11. Retrieved 2022-06-17.
  2. ^ "Archive files". www.ibm.com. 2015-02-07. Archived from the original on 2023-09-07. Retrieved 2022-06-17.
  3. ^ "What is Archiving And Why is it Important?". Secure Data MGT. 2015-03-23. Archived from the original on 2022-05-24. Retrieved 2022-06-17.
  4. ^ "Data Portability and Platform Competition | Is User Data Exported From Facebook Actually Useful to Competitors?". Archive.org. p. 22. Retrieved June 17, 2022.
  5. ^ "Why file transfer speeds of small vs large files could be different". NetApp Knowledge Base. 2020-06-17. Archived from the original on 2022-01-01. Retrieved 2022-06-17.
  6. ^ "Why Small Files Take Longer to Copy Than Large Files". Dataquest. 2018-10-10. Archived from the original on 2022-07-02. Retrieved 2022-06-17.
  7. ^ Ashbel, Amit. "Data Archiving: The Basics and 5 Best Practices". cloud.netapp.com. Archived from the original on 2022-01-19. Retrieved 2022-06-17.
  8. ^ Drummond, James R. (1997). Parity, Checksums and CRC Checks (PDF) (1st ed.). Toronto. p. 13. Archived (PDF) from the original on 2020-10-31. Retrieved 2022-06-17.{{cite book}}: CS1 maint: location missing publisher (link)
  9. ^ text. "What are PAR and PAR2 Files?". Easynews. Archived from the original on 2024-07-11. Retrieved 2022-06-17.
  10. ^ "What are Archive Files?". www.exefiles.com. Archived from the original on 2022-05-28. Retrieved 2022-06-17.
  11. ^ "What Is a File Extension & Why Are They Important?". Lifewire. Archived from the original on 2022-06-03. Retrieved 2022-06-17.
  12. ^ "Common file name extensions in Windows". support.microsoft.com. Archived from the original on 2022-05-27. Retrieved 2022-06-17.
  13. ^ Malefanem, Moses. "Learning Java Network Programming". Archived from the original on 2023-09-07. Retrieved 2022-06-17.
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