- data can be 'squeezed' so it doesn't take up so much space
- they can also be encrypted to prevent unauthorized persons from using them
- the resulting archive can be divided into parts, for example, the size of a floppy disk
- data can be equipped with checksums so that if the diskette is damaged, the incorrect location can be recalculated without losing information
- the archive can be supplemented with information about who created it (similar to a digital signature)
There are many products on the market offering the basic functions mentioned, e.g. ZIP, ARJ, TAR/GZ, ACE, LHARC, etc., and they differ from each other both in how they perform these basic functions (see e.g. Archive Comparison Test) and in that they offer other, for some significant improvements, such as the ability to automatically generate names by date, selection by date, archiving flags, the ability to work with 'long' names, self-extracting archives, the ability to lock the archive against further modification, interactive control, archive comments, the ability to use a multi-core computer, etc.
Compared to the competition, WinRAR stands out primarily for its optimal ratio of speed to compression efficiency. There are products that can compress the given data a few percent better, but it takes several times longer. Or a few percent faster, but tens of percent less compressed.
Another distinctive feature of RAR is that archives can be worked with interactively using a graphical interface and also allows you to prepare batches for automatic, unattended archiving using command line parameters.
In addition to the most widespread Wintel platform, RAR archives can be used in Unix, Linux, MacIntosh, IBM OS/2 environments... Since the author comes from an area where the Cyrillic alphabet is commonly used, there are far fewer problems with national characters in different code pages, even in the Czech environment, compared to the competition.
The RAR implementation for Windows is called WinRAR and, in addition to its own RAR format, it can also create archives in the most widely used ZIP format and read archives in other published formats: ARJ, LZH, ACE, CAB, TAR, GZip, UUE, BZ2, JAR, 7-Zip, ISO, Z.
RAR uses a relatively strong block cipher for encryption, so even though there are many password cracking programs floating around the internet, with a password of 6 or more characters, finding the password using current technology takes several decades, unlike other formats, where it takes a few hours.
Another interesting feature of RAR is the ability to create self-extracting archives, where the extraction can be controlled by a script to the point that in simpler cases it can even replace the use of InstallShield(r) or a similar tool.
RAR can also fully utilize current computers with multiple processors, where classic programs usually work in a single thread and leave the other processors idle.
