Archive file

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In computing, an archive file is a computer file that is composed of one or more files along with metadata. Many archive formats also support compression of member files. 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. Archive files often store directory structures, error detection and correction information, comments, and some use built-in encryption. [1] [2] [3]

Contents

Applications

Portability

Archive files are particularly useful in that they store file system data and metadata within the contents of a particular file, and thus can be stored on systems or sent over channels that do not support the file system in question, only file contents – examples include sending a directory structure over email, files with names unsupported on the target file system due to length or characters, and retaining files' date and time information. [4]

A single archive file may contain multiple member files; this can speed file transfers and other operations with processing overheads for each file, [5] [6] in addition to gains due to compression.

Software distribution

Beyond archival purposes, archive files are frequently used for packaging software for distribution, as software contents are often naturally spread across several files; the archive is then known as a package. While the archival file format is the same, there are additional conventions about contents, such as requiring a manifest file, and the resulting format is known as a package format. [7] Examples include deb for Debian, JAR for Java, APK for Android, and self-extracting Windows Installer executables.

Features

Features supported by various kinds of archives include:

Some archive programs have self-extraction, self-installation, source volume and medium information, and package notes/description.

The file extension or file header of the archive file are indicators of the file format used. Computer archive files are created by file archiver software, optical disc authoring software, and disk image software. [8]

Archive formats

An archive format is the file format of an archive file. Some formats are well-defined by their authors and have become conventions supported by multiple vendors and communities. [9]

Types

Examples

Filename extensions used to distinguish different types of archives include zip, rar, 7z, and tar, the first of which is the most widely implemented. [10]

Java also introduced a whole family of archive extensions such as jar and war (j is for Java and w is for web). They are used to exchange entire byte-code deployment. Sometimes they are also used to exchange source code and other text, HTML and XML files. By default they are all compressed. [11]

Error detection and recovery

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). [12]

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. [13]

See also

Related Research Articles

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. File archivers may employ lossless data compression in their archive formats to reduce the size of the archive.

Waveform Audio File Format is an audio file format standard for storing an audio bitstream on personal computers. The format was developed and published for the first time in 1991 by IBM and Microsoft. It is the main format used on Microsoft Windows systems for uncompressed audio. The usual bitstream encoding is the linear pulse-code modulation (LPCM) format.

<span class="mw-page-title-main">FLAC</span> Lossless digital audio coding format

FLAC is an audio coding format for lossless compression of digital audio, developed by the Xiph.Org Foundation, and is also the name of the free software project producing the FLAC tools, the reference software package that includes a codec implementation. Digital audio compressed by FLAC's algorithm can typically be reduced to between 50 and 70 percent of its original size and decompresses to an identical copy of the original audio data.

A filename extension, file name extension or file extension is a suffix to the name of a computer file. The extension indicates a characteristic of the file contents or its intended use. A filename extension is typically delimited from the rest of the filename with a full stop (period), but in some systems it is separated with spaces.

In computing, tar is a computer software utility for collecting many files into one archive file, often referred to as a tarball, for distribution or backup purposes. The name is derived from "tape archive", as it was originally developed to write data to sequential I/O devices with no file system of their own, such as devices that use magnetic tape. The archive data sets created by tar contain various file system parameters, such as name, timestamps, ownership, file-access permissions, and directory organization. POSIX abandoned tar in favor of pax, yet tar sees continued widespread use.

ZIP is an archive file format that supports lossless data compression. A ZIP file may contain one or more files or directories that may have been compressed. The ZIP file format permits a number of compression algorithms, though DEFLATE is the most common. This format was originally created in 1989 and was first implemented in PKWARE, Inc.'s PKZIP utility, as a replacement for the previous ARC compression format by Thom Henderson. The ZIP format was then quickly supported by many software utilities other than PKZIP. Microsoft has included built-in ZIP support in versions of Microsoft Windows since 1998 via the "Plus! 98" addon for Windows 98. Native support was added as of the year 2000 in Windows ME. Apple has included built-in ZIP support in Mac OS X 10.3 and later. Most free operating systems have built in support for ZIP in similar manners to Windows and macOS.

<span class="mw-page-title-main">JAR (file format)</span> Java archive file format

A JAR file is a package file format typically used to aggregate many Java class files and associated metadata and resources into one file for distribution.

RAR is a proprietary archive file format that supports data compression, error correction and file spanning. It was developed in 1993 by Russian software engineer Eugene Roshal and the software is licensed by win.rar GmbH. The name RAR stands for Roshal Archive.

StuffIt is a discontinued family of computer software utilities for archiving and compressing files. Originally produced for Macintosh, versions for Microsoft Windows, Linux (x86), and Sun Solaris were later created. The proprietary compression format used by the StuffIt utilities is also termed StuffIt.

deb is the format, as well as filename extension of the software package format for the Debian Linux distribution and its derivatives.

ARC is a lossless data compression and archival format by System Enhancement Associates (SEA). The file format and the program were both called ARC. The format is known as the subject of controversy in the 1980s, part of important debates over what would later be known as open formats.

Executable compression is any means of compressing an executable file and combining the compressed data with decompression code into a single executable. When this compressed executable is executed, the decompression code recreates the original code from the compressed code before executing it. In most cases this happens transparently so the compressed executable can be used in exactly the same way as the original. Executable compressors are often referred to as executable packers, runtime packers, software packers, software protectors, or even "polymorphic packers" and "obfuscating tools".

The following tables compare general and technical information for a number of file systems.

<span class="mw-page-title-main">Self-extracting archive</span> Computer executable program

A self-extracting archive is a computer executable program which combines compressed data in an archive file with machine-executable code to extract the information. Running on a compatible operating system, it does not need a suitable extractor in the target computer to extract the data. The executable part of the file is known as a decompressor stub.

XAR is an open source file archiver and the archiver’s file format. It was created within the OpenDarwin project and is used in macOS X 10.5 and up for software installation routines, as well as browser extensions in Safari 5.0 and up. Xar replaced the use of gzipped pax files.

<span class="mw-page-title-main">Apple Disk Image</span> File format developed by Apple and used by macOS

AppleDisk Image is a disk image format commonly used by the macOS operating system. When opened, an Apple Disk Image is mounted as a volume within the Finder.

Resilient File System (ReFS), codenamed "Protogon", is a Microsoft proprietary file system introduced with Windows Server 2012 with the intent of becoming the "next generation" file system after NTFS.

ZFS is a file system with volume management capabilities. It began as part of the Sun Microsystems Solaris operating system in 2001. Large parts of Solaris, including ZFS, were published under an open source license as OpenSolaris for around 5 years from 2005 before being placed under a closed source license when Oracle Corporation acquired Sun in 2009–2010. During 2005 to 2010, the open source version of ZFS was ported to Linux, Mac OS X and FreeBSD. In 2010, the illumos project forked a recent version of OpenSolaris, including ZFS, to continue its development as an open source project. In 2013, OpenZFS was founded to coordinate the development of open source ZFS. OpenZFS maintains and manages the core ZFS code, while organizations using ZFS maintain the specific code and validation processes required for ZFS to integrate within their systems. OpenZFS is widely used in Unix-like systems.

References

  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. ↑ "What Is a File Extension & Why Are They Important?". Lifewire. Archived from the original on 2022-06-03. Retrieved 2022-06-17.
  9. ↑ "What are Archive Files?". www.exefiles.com. Archived from the original on 2022-05-28. Retrieved 2022-06-17.
  10. ↑ "Common file name extensions in Windows". support.microsoft.com. Archived from the original on 2022-05-27. Retrieved 2022-06-17.
  11. ↑ Malefanem, Moses. "Learning Java Network Programming". Archived from the original on 2023-09-07. Retrieved 2022-06-17.
  12. ↑ 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)
  13. ↑ text. "What are PAR and PAR2 Files?". Easynews. Archived from the original on 2024-07-11. Retrieved 2022-06-17.
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