1.3 – the first public version, does not have the 'Rar!' signature.

The minimum size of a RAR file is 20 bytes. Version 3 of RAR is based on Lempel-Ziv ( LZSS) and prediction by partial matching (PPM) compression, specifically the PPMd implementation of PPMII by Dmitry Shkarin. Roshal, the elder brother of Eugene Roshal, owns the copyright. 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. Numbers were used in the file extensions of the smaller files to keep them in the proper sequence. Previous versions of RAR split large archives into several smaller files, creating a 'multi-volume archive'.

It was developed in 1993 by Russian software engineer Eugene Roshal and the software is licensed by win.rar GmbH. RAR is a proprietary archive file format that supports data compression, error correction and file spanning. No (decompression source code available, but not free software, due to restriction that it not be used to create RAR-compatible archives)

Software rar