RAR is an archive file format that includes essential features like error recovery, file spanning, and data compression. The term RAR was derived from its developer, a Russian software engineer named Eugene Roshal (from Roshal ARchive).
The file format .rar is used for data volume sets. On the other hand, .rev is the format for recovery volume sets. There are different versions of the RAR application. These are the original RAR, RAR2, and the latest, RAR3.
The RAR3 version can undergo changes in file name extensions, the encryption algorithm, the compression algorithm, the Recovery Volumes option, and support for large files.
The RAR file format was first created for packing and unpacking files for the DOS programs. However, it was later adopted by various other platforms. Shareware versions are also available for Mac OS X, Linux, DOS, OS/2, and FreeBSD.
The rate of compression is not the only feature available in RAR.
- It can also handle split volumes with much efficiency. Before the introduction of the RAR format, ARJ was the most widely used compression software.
- It can add multiple “recovery records” (also redundancy) into an archive. This prevents the corruption of the file. While some parts of the archive might suffer from damage, RAR can still recover the data when there is a large percentage of recovery record.
- The archived file can be considered a single block of data.
- It has strong encryption capabilities. The older versions use proprietary algorithm, while the new ones use AES encryption algorithm.
- The newer versions are equipped with a password protection feature, so users who don’t have the correct password cannot display the archived files.
- It can handle extended attributes for OS/2.
- RAR files can be embedded in other files types, most commonly JPEG.
RAR vs. Other Compression Algorithms
It is said that the compression operation for most RAR files are slower than when you compress the same file on WinZIP or gzip. WinZIP has a much better compression rate as compared with the RAR format.
On the other hand, the LZMA algorithm has similarities with the RAR format. Both of them need more or less a similar amount of time to compress or decompress the same file.
Both the ZIP and LZMA are still widely used today as a compression scheme, just as much as RAR.