Advanced file compression

When it comes to compressing files and folders stored on a PC’s hard disk, most people will have heard of a Zip file. It is so ubiquitous that the file format is even supported by Windows. But Zip isn’t the only file-compression format. In fact, there are dozens, some of which are better than Zip.

In this Masterclass, we are going to focus on the Rar compression format. It offers better compression, advanced encryption facilities and support for large files.

It is named after its inventor, Eugene Roshal (Rar being a contraction of Roshal Archive), and while the format can be read by a number of compression tools, it can only be created using Winrar.

A trial version of Winrar can be downloaded free at www.computeractive.co.uk/2128941, and although the unregistered version of the software sometimes prompts you to pay, it remains fully functional if you decline.

If you want to continue using it without the nag screen it costs €29.95 (around £26). Here’s how to get working with Rar.

Why Rar?
The Zip file is far from being the only compressed file format in existence ­ there are so many, in fact, that there is a format for virtually every letter of the alphabet: .ace, .arc, .cab, .dgc, .ice, .jar, .kgb, .lzh, .pea, to name but a few.

One of the reasons the Zip format is so popular is at least partly attributed to the fact that Windows XP onwards has allowed for the creation and extraction of such compressed files without the need for additional software.

Through the use of Compressed Folder, Windows XP and Vista have allowed files and folders to be transformed into compressed Zip files with little more than a couple of mouse clicks. Users of Windows XP can also create password-protected Zip files, but this option was dropped from Vista.

While the Zip format is most popular, it does not necessarily mean it is the best. As mentioned, there are archive formats that offer higher levels of compression ­ and Rar is foremost among them.

The Rar format also supports split archives (a compressed archive that is spread over several files for easier uploading or emailing, say; the split archives can then be rejoined to form a single file), strong encryption options and support for recovery records, which help to protect files against corruption.