RPM files consist of metadata concatenated with (usually) a cpio archive. Newer RPM systems also support other archives, as cpio is becoming obsolete. cpio is also used with initramfs.
A system for storing multiple files. LBR archives typically contained files processed by SQ, or the archive itself was compressed with SQ. LBR archives that were compressed with SQ ended with the extension .LQR
An archive format originally used mainly for archiving and distribution of the exact, nearly-exact, or custom-modified contents of an optical storage medium such as a CD-ROM or DVD-ROM. However, it can be used to archive the contents of other storage media, selected partitions, folders, and/or files. The resulting archive is typically optimized for convenient rendering to (re-)writable CD or DVD media.
.lbr
Commodore 64/128
A library format used primarily on the Commodore 64 and 128 lines of computers. This bears no resemblance to the DOS LBR format. While library files were quick to implement (a number of programs exist to work with them) they are crippled in that they cannot grow with use: once a file has been created it cannot be amended (files added, changed or deleted) without recreating the entire file.
A common archive format used on Unix-like systems. Generally used in conjunction with compressors such as gzip, bzip2, compress or xz to create .tar.gz, .tar.bz2, .tar.Z or tar.xz files.
Brotli is a compression algorithm developed by Google for textual web content, and typically achieves higher compression ratios than other algorithms for this use case.
A compression format developed by Google, and open-sourced in 2011. Snappy aims for very high speeds, reasonable compression, and maximum stability rather than maximum compression or compatibility with any other compression library. It is an LZ77 derivative, without entropy encoding.
Squeeze: A program which compressed files using Huffman coding. A file which was "squeezed" had the middle initial of the name changed to "Q", so that a squeezed text file would end with .TQT, a squeezed executable would end with .CQM or .EQE. Typically used with .LBR archives, either by storing the squeezed files in the archive, or by storing the files decompressed and then compressing the archive, which would have a name ending in ".LQR".
A compression program written by Steven Greenberg implementing the LZW algorithm. For several years in the CP/M world when no implementation was available of ARC, CRUNCHed files stored in .LBR archives were very popular. CRUNCH's implementation of LZW had a somewhat unusual feature of modifying and occasionally clearing the code table in memory when it became full, resulting in a few percent better compression on many files.
A compression format using LZMA2 to yield high compression ratios. The LZMA algorithm is an LZ77 derivative, with entropy encoding in the form of range encoding.
Compression format(s) used by some DOS and Windows install programs. MS-DOS includes expand.exe to decompress its install files. The compressed files are created with a matching compress.exe command. The compression algorithm is LZSS.
macOS, restoration on different platforms is possible although not immediate
Yes
Based on 7z. Preserves Spotlight metadata, resource forks, owner/group information, dates and other data which would be otherwise lost with compression.
Made obsolete by the introduction of AppleDouble-encoded 7z archives (Macintosh only).
A format that compresses and doubly encrypt the data (AES256 and CAS256) avoiding brute force attacks, also hide files in an AFA file. It has two ways to safeguard data integrity and subsequent repair of the file if has an error (repair with AstroA2P (online) or Astrotite (offline)).
Created by Yaakov Gringeler; released last in 2003 (Compressia 1.0.0.1 beta), now apparently defunct. Free trial of 30 days lets user create and extract archives; after that it is possible to extract, but not to create.
Supports "Internet-enabled" disk images, which, once downloaded, are automatically decompressed, mounted, have the contents extracted, and thrown away. Currently, Safari is the only browser that supports this form of extraction; however, the images can be manually extracted as well. This format can also be password-protected or encrypted with 128-bit or 256-bit AES encryption.
Open source archiver supporting authenticated encryption, cascaded encryption, volume spanning, customizable object level and volume level integrity checks (form CRCs to SHA-512 and Whirlpool hashes), fast deflate based compression
A package format to enable distribution of applications and libraries by bundling many PHP code files and other resources (e.g. images, stylesheets, etc.) into a single archive file
The format from the PIM - a freeware compression tool by Ilia Muraviev. It uses an LZP-based compression algorithm with set of filters for executable, image and audio files.
The format from a commercial archiving package. Odd among commercial packages in that they focus on incorporating experimental algorithms with the highest possible compression (at the expense of speed and memory), such as PAQ, PPMD and PPMZ (PPMD with unlimited-length strings), as well as a proprietary algorithms.
.sda
Self Dissolving ARChive
Commodore 64, Commodore 128
Commodore 64, Commodore 128
Yes
SDAs refer to Self Dissolving ARC files, and are based on the Commodore 64 and Commodore 128 versions of ARC, originally written by Chris Smeets. While the files share the same extension, they are not compatible between platforms. That is, an SDA created on a Commodore 64 but run on a Commodore 128 in Commodore 128 mode will crash the machine, and vice versa. The intended successor to SDA is SFX.
A pre-Mac OS X Self-Extracting Archive format. StuffIt, Compact Pro, Disk Doubler and others could create .sea files, though the StuffIt versions were the most common.
.sen
Scifer
Multiple
Multiple
Yes
Scifer Archive with internal header
.sfx
Self Extracting Archive
Commodore 64, Commodore 128
Commodore 64, Commodore 128
Yes
SFX is a Self Extracting Archive which uses the LHArc compression algorithm. It was originally developed by Chris Smeets on the Commodore platform, and runs primarily using the CS-DOS extension for the Commodore 128. Unlike its predecessor SDA, SFX files will run on both the Commodore 64 and Commodore 128 regardless of which machine they were created on.
An archive format designed for the Apple II series of computers. The canonical implementation is ShrinkIt, which can operate on disk images as well as files. Preferred compression algorithm is a combination of RLE and 12-bit LZW. Archives can be manipulated with the command-line NuLib tool, or the Windows-based CiderPress.
The replacement for the .sit format that supports more compression methods, UNIX file permissions, long file names, very large files, more encryption options, data specific compressors (JPEG, Zip, PDF, 24-bit image, MP3). The free StuffIt Expander is available for Windows and OS X.
The "tarball" format combines tar archives with a file-based compression scheme (usually gzip). Commonly used for source and binary distribution on Unix-like platforms, widely available elsewhere. Xarchiver supports the .tar.zst Archive/Compression format on Unix-like platforms.
UltraCompressor 2.3 was developed to act as an alternative to the then popular PKZIP application. The main feature of the application is its ability to create large archives. This means that compressed archives with the UC2 file extension can hold almost 1 million files.
Based on PAQ, RZM, CSC, CCM, and 7zip. The format consists of a PAQ, RZM, CSC, or CCM compressed file and a manifest with compression settings stored in a 7z archive.
Native format of the Open Source KiriKiriVisual Novel engine. Uses combination of block splitting and zlib compression. The filenames and pathes are stored in UTF-16 format. For integrity check, the Adler-32 hashsum is used. For many commercial games, the files are encrypted (and decoded on runtime) via so-called "cxdec" module, which implements xor-based encryption.
Yamazaki zipper archive. Compression format used in DeepFreezer archiver utility created by Yamazaki Satoshi. Read and write support exists in TUGZip, IZArc and ZipZag
Journaling (append-only) archive format with rollback capability. Supports deduplication and incremental update based on last-modified dates. Multi-threaded. Compresses in LZ77, BWT, and context mixing formats. Open source.
File format used in conjunction with any archive format to provide error correction and file recovery, most often in newsgroup distribution of binary files.
File format used with WinRAR rar volumes. The data recovery is error correction data which is provided in the form of open recovery records and/or recovery volumes, allowing reconstruction of good archives (including reconstruction of entirely volumes)
^1 While the original tar format uses the ASCII character encoding, current implementations use the UTF-8 (Unicode) encoding, which is backwards compatible with ASCII. ^2 Supports the external Parchive program (par2). ^3 From 3.20 release RAR can store modification, creation and last access time with the precision up to 0.0000001 second (= 0.1 µs). WinRAR download and support: Knowledge Base ^4 The PAQ family (with its lighter weight derivative LPAQ) went through many revisions, each revision suggested its own extension. For example: ".paq9a". ^5 WIM can store the ciphertext of encrypted files on an NTFS volume, but such files can only by decrypted if an administrator extracts the file to an NTFS volume, and the decryption key is available (typically from the file's original owner on the same Windows installation). Microsoft has also distributed some download versions of the Windows operating system as encrypted WIM files, but via an external encryption process and not a feature of WIM.
Purpose: Archive formats are used for backups, mobility, and archiving. Many archive formats compress the data to consume less storage space and result in quicker transfer times as the same data is represented by fewer bytes. Another benefit is that files are combined into one archive file which has less overhead for managing or transferring. There are numerous compression algorithms available to losslessly compress archived data; some algorithms are designed to work better (smaller archive or faster compression) with particular data types. Archive formats are used by most operating systems to package software for easier distribution and installation than binary executables.
Filename extension: The DOS and Windows operating systems required filenames to include an extension (of at least one, and typically 3 characters) to identify the file type. Such extensions must be unique for each type of file. Many operating systems identify a file's type from its contents without the need for an extension in its name. However, the use of three-character extensions has been embraced as a useful and efficient shorthand for identifying file types.
Integrity check: Archive files are often stored on magnetic or other media subject to storage errors. Many archive formats contain extra error detection or correction information which can be used by the software used to read the archive files to detect and possibly correct errors.
Recovery record: Many archive formats contain redundant data embedded in the files in order to detect data storage or transmission errors, and the software used to read the archive files contains logic to detect and correct errors.
Encryption: Many archive formats include the capability to encrypt contents to prevent unauthorised access, using one of many available encryption methods.
^1 Compression is not a built-in feature of the formats, however, the resulting archive can be compressed with any algorithm of choice. Several implementations include functionality to do this automatically ^2 Most implementations can optionally produce a self-extracting executable ^3 Per-file compression with gzip, bzip2, lzo, xz, lzma (as opposed to compressing the whole archive). An individual can choose not to compress already compressed filenames based on their suffix as well.
1 2 3 4 File extensions may differ across platforms. The case of these extensions may differ on case-insensitive platforms.
1 2 3 4 MIME media types may be conjectural. Very few have been officially registered with the IANA. Compression-only formats should often be denoted by the media type of the decompressed data, with a content coding indicating the compression format.
1 2 3 4 Creation platform indicates the platform(s) under which a format can be created.
↑ If attaching .F to the file name is not possible with the DOS operating system, the second and third character of the filename extension are replaced by XF.
↑ Restoration platform indicates the platform(s) under which a format can be restored/extracted. Most file formats can be understood by more than one platform.
↑ "Restorable with free software" indicates whether the format can be restored using an extraction tool that is free software.
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.
gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and intended for use by GNU. Version 0.1 was first publicly released on 31 October 1992, and version 1.0 followed in February 1993.
zlib is a software library used for data compression as well as a data format. zlib was written by Jean-loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. zlib is also a crucial component of many software platforms, including Linux, macOS, and iOS. It has also been used in gaming consoles such as the PlayStation 4, PlayStation 3, Wii U, Wii, Xbox One and Xbox 360.
New Technology File System (NTFS) is a proprietary journaling file system developed by Microsoft. Starting with Windows NT 3.1, it is the default file system of the Windows NT family. It superseded File Allocation Table (FAT) as the preferred filesystem on Windows and is supported in Linux and BSD as well. NTFS reading and writing support is provided using a free and open-source kernel implementation known as NTFS3 in Linux and the NTFS-3G driver in BSD. By using the convert command, Windows can convert FAT32/16/12 into NTFS without the need to rewrite all files. NTFS uses several files typically hidden from the user to store metadata about other files stored on the drive which can help improve speed and performance when reading data. Unlike FAT and High Performance File System (HPFS), NTFS supports access control lists (ACLs), filesystem encryption, transparent compression, sparse files and file system journaling. NTFS also supports shadow copy to allow backups of a system while it is running, but the functionality of the shadow copies varies between different versions of Windows.
In computing, Deflate is a lossless data compression file format that uses a combination of LZ77 and Huffman coding. It was designed by Phil Katz, for version 2 of his PKZIP archiving tool. Deflate was later specified in RFC 1951 (1996).
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.
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.
7-Zip is a free and open-source file archiver, a utility used to place groups of files within compressed containers known as "archives". It is developed by Igor Pavlov and was first released in 1999. 7-Zip has its own archive format called 7z, but can read and write several others.
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 License. The LZMA SDK 4.62 was placed in the public domain in December 2008. The latest stable version of 7-Zip and LZMA SDK is version 22.01.
StuffIt is a discontinued family of computer software utilities for archiving and compressing files. Originally produced for the 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.
WinRAR is a trialware file archiver utility for Windows, developed by Eugene Roshal of win.rar GmbH. It can create and view archives in RAR or ZIP file formats, and unpack numerous archive file formats. To enable the user to test the integrity of archives, WinRAR embeds CRC32 or BLAKE2 checksums for each file in each archive. WinRAR supports creating encrypted, multi-part and self-extracting archives.
The following tables compare general and technical information for a number of file archivers. Please see the individual products' articles for further information. They are neither all-inclusive nor are some entries necessarily up to date. Unless otherwise specified in the footnotes section, comparisons are based on the stable versions—without add-ons, extensions or external programs.
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.
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. Run on a compatible operating system, there is no need for a suitable extractor in the target computer to extract the data. The executable part of the file is known as a decompressor stub.
PeaZip is a free and open-source file manager and file archiver for Microsoft Windows, ReactOS, Linux, MacOS and BSD by Giorgio Tani. It supports its native PEA archive format and other mainstream formats, with special focus on handling open formats. Version 9.4.0 supported 234 file extensions.
XZ Utils is a set of free software command-line lossless data compressors, including the programs lzma and xz, for Unix-like operating systems and, from version 5.0 onwards, Microsoft Windows. For compression/decompression the Lempel–Ziv–Markov chain algorithm (LZMA) is used. XZ Utils started as a Unix port of Igor Pavlov's LZMA-SDK that has been adapted to fit seamlessly into Unix environments and their usual structure and behavior.
FreeArc is a free and open-source high-performance file archiver developed by Bulat Ziganshin. The project is presumably discontinued, since no information has been released by the developers since 2016 and the official website is down.
lzip is a free, command-line tool for the compression of data; it employs the Lempel–Ziv–Markov chain algorithm (LZMA) with a user interface that is familiar to users of usual Unix compression tools, such as gzip and bzip2.
Zstandard is a lossless data compression algorithm developed by Yann Collet at Facebook. Zstd is the corresponding reference implementation in C, released as open-source software on 31 August 2016.
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