Editing RAR (file format) (section)

== File format ==
The [[filename extension]]s used by RAR are <code>.rar</code> for the data volume set and <code>.rev</code> for the recovery volume set. Previous versions of RAR split large archives into several smaller files, creating a "multi-volume archive".  Numbers were used in the file extensions of the smaller files to keep them in the proper sequence.  The first file used the extension <code>.rar</code>, then <code>.r00</code> for the second, and then <code>.r01</code>, <code>.r02</code>, etc.

RAR compression applications and libraries (including GUI based [[WinRAR]] application for Windows, console rar utility for different OSes and others) are proprietary software, to which Alexander L. Roshal,<ref name="rar_eula" /> the elder brother of [[Eugene Roshal]], holds the copyright. Version 3 of RAR is based on [[LZ77 and LZ78|Lempel-Ziv]] ([[LZSS]]) and [[prediction by partial matching]] (PPM) compression, specifically the PPMd implementation of PPMII by Dmitry Shkarin.<ref>{{cite web|url=http://www.unrarlib.org/faq.html|title=unrarlib FAQ|author=Christian Scheurer|date=2006-12-17}}</ref>

The minimum size of a RAR file is 20 bytes. The maximum size of a RAR file is [[9,223,372,036,854,775,807]] (2<sup>63</sup>−1) bytes, which is one byte less than 8 [[exbibyte|EiB]].<ref>{{cite web |url=http://www.softpedia.com/get/Compression-tools/WinRAR.shtml |url-status=deviated |archive-url=https://web.archive.org/web/20130720122901/http://www.softpedia.com/get/Compression-tools/WinRAR.shtml |archive-date=2013-07-20 |access-date=2013-05-01 |title=WinRAR description}}</ref>

===Versions===
The RAR file format revision history:
* 1.3 – the first public version, does not have the "Rar!" signature.
* 1.5 – changes are not known.
* 2.0 – released with WinRAR 2.0 and Rar for MS-DOS 2.0; features the following changes:
** Multimedia compression for true color bitmap images and uncompressed audio.
** Up to 1 [[Megabyte|MB]] compression dictionary.
** Introduces archives data recovery protection record.
* 2.9<ref group="note">WinRAR 5.0 and RAR for Android refer to this format as RAR4.</ref> – released in WinRAR version 3.00.  Feature changes in this version include:
** File extensions is changed from ''{volume name}.rar, {volume name}.r00, {volume name}.r01, etc.'' to ''{volume name}.part001.rar, {volume name}.part002.rar, etc.''
** Encryption of both file data and file headers.
** Improves compression algorithm using 4 [[megabyte|MB]] dictionary size, Dmitry Shkarin's [[Prediction by partial matching|PPMII algorithm]] for file data.
** Optional creation of "recovery volumes" (.rev files) for [[Error correction code|error correction]], which can be used to reconstruct missing files in a volume set.
** Support for archive files larger than 9 [[gigabyte|GB]].
** Support for [[Unicode]] file names stored in [[UTF-16]] little endian format.
* 5.0 – supported by WinRAR 5.0 (released April 2013) and later.<ref>[https://www.ghacks.net/2013/04/29/winrar-5-0-introduces-the-new-rar-5-format-what-you-need-to-know/ WinRAR 5.0 introduces the new RAR 5 format. What you need to know] - ghacks.net</ref> Changes in this version:
** Maximum compression dictionary size increased to 1 [[gigabyte|GB]] (default for WinRAR 5.x is 32 [[megabyte|MB]] and 4 MB for WinRAR 4.x).
** Maximum path length for files in RAR and ZIP archives is increased up to 2048 characters.
** Support for [[Unicode]] file names stored in [[UTF-8]] format.
** Faster compression and decompression.
** Multicore decompression support.
** Greatly improves recovery.
** Optional [[Advanced Encryption Standard|AES]] encryption increased from 128-bit to 256-bit.
** Optional 256-bit [[BLAKE2]] file hash instead of a default 32-bit [[CRC32]] file checksum.
** Optional duplicate file detection.
** Optional [[NTFS]] hard and symbolic links.
** Optional Quick Open Record. Rar4 archives had to be parsed before opening as file names were spread throughout the archive, slowing operation particularly with slower devices such as optical drives, and reducing the integrity of damaged archives. Rar5 can optionally create a "quick open record", a special archive block at the end of the file that contains the names of files included, allowing archives to be opened faster.
** Removes specialized compression algorithms for Itanium executables, text, raw audio (WAV), and raw image (BMP) files; consequently some files of these types compress better in the older RAR (4) format with these options enabled than in RAR5.
* 5.0+ – partially supported by WinRAR 5.0 and later. Fully supported by WinRAR 7.0 (released February 2024<ref>[https://www.win-rar.com/singlenewsview.html?&L=0&tx_ttnews%5Btt_news%5D=251&cHash=843e9e875ad0ca0e28e4b14ef34d17cd WinRAR News: WinRAR 7.00 Final released]</ref>) and later. Changes in this version:
** Compression dictionary up to 64 [[gigabyte|GB]].
** Improved compression by the addition of "Alternate search algorithm".
** Maximum path length limit increased from 2047 to 65535 characters.

;Notes
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