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WinRAR

File archiver

  • 9 min read
  • 6 chapters

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Through Microsoft Windows, DOS and Java (programming language)

RARLAB also offers a mobile version as freeware for Android under the name RAR for Android. Related programs include command-line utilities RAR and UNRAR which are also released for macOS, Linux, FreeBSD, and in the past for Windows CE, MS-DOS and OS/2.

Evolution

RAR/DOS started as a mix of x86 assembler and C, with the amount of assembly code decreasing over time and moving to pure C/C++ later on. The first versions of WinRAR were written in C; modern versions predominantly use C++. RAR for Android is written as a mixture of Java and C++.

WinRAR and the RAR file format have evolved over time. Support for the archive format RAR5, using the same RAR file extension as earlier versions, was added in version 5.0; the older RAR file format has since been referred to as RAR4. WinRAR versions before 5.0 do not support RAR5 archives; only older versions of WinRAR run on older operating systems, and cannot open RAR5 archives.

The RAR5 file format – from version 7 on, referred to as "RAR" – increased the maximum dictionary size up to 64 GB, depending on the amount of available memory, with the default in version 5 increased from 4 MB to 32 MB, typically improving compression ratio. For dictionaries larger than 4 GB, the size can be specified if it is unequal to a power of 2. Thus, there are no restrictions to the range 4, 8, 16, 32, 64, allowing 5 GB or 22 GB to be chosen at will. Archives with dictionaries larger than 4 GB can only be extracted by WinRAR 7.0 or newer. AES encryption, when used, is in CBC mode and was increased in strength from 128- to 256-bit. Maximum path length for files in RAR and ZIP archives is increased from 2047 to 65535 characters.

Options added in v5.0 include 256-bit BLAKE2 file-hashing algorithm instead of default 32-bit CRC-32, duplicate file detection, NTFS hard and symbolic links, and Quick Open record to allow large archives to be opened faster.

The RAR5 file format removed comments for each file (though archive comment still remains), authenticity verification, and specialized compression algorithms for text and multimedia files. RAR5 also changed the file name for split volumes from archivename.rNN to archivename.partNN.rar.

The RAR7 file format added support for 64GB compression dictionary and improved compression ratio by adding two extra algorithms. RAR7 archives with dictionary sizes up to 4 GB can be unpacked by previous versions of WinRAR (5.0 and above) given there's enough RAM.

On the 31st of May 2024, WinRAR announced that they would no longer offer the physical CD-ROM delivery option due to the factory that produces them shutting, citing a lack of demand and support for optical media.

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