When introducing for the first time his ‘Time Machine’ back in October 2007, Steve Jobs briefly mentioned that, based on a survey made by Apple, only about 5% of PC users use an automated backup software to protect their data against hard disk failures or accidental data loss. The aim of Apple's new software would therefore be to radically invert this trend by providing Apple users with a both powerful and easy-to-use tool that would automate the backup process and make the ‘rollback’ procedure an easy, even enjoyable user experience.
While Jobs’ and Apple's data could in fact have been biased for the sake of presentation effectiveness, it is certainly true that the practice of regularly backing up your personal data, while being undoubtedly useful and highly advisable, is practiced by a very small portion of PC users. Arguably, the two main reasons for this are the increased cost - as it's best practice to use a separate hard drive to store backup data - and, most of all, because free backup software utilities are either rare or little known to the general public.
Apart the aforementioned ‘Time Machine', which comes free with Mac OS X Leopard (but confine you to a proprietary operating system), there are at least a few tools that deserve our attention.
Some fairly advanced tools for Microsoft Windows include ‘Back2zip', ‘JustZIPit’ or ‘SyncBackSE’.
Back2zip tends to be the backup program with the best user ratings and reviews at such sites as Download.com and similar. It features an intuitive user interface, and it has an option to make every day backup, plus updates every 6 hours to 20 minutes. As it's to be expected in these kinds of programs, while the first backup will take quite a bit of time, the following ones will tend to be much faster.
JustZIPit is probably using more efficient algorithms as it seems to be easier on the CPU, with the option of running it in the background in order to enable you to continue working on your machine even while file operations are taking place. The UI is extremely simple and takes the away all the unnecessary.
Finally, SyncBackSE is another useful backup and folder synchronization utility. However, its interface somehow looks as too much of a compromise between the ‘newbie’ and the ‘geek’ category, and is trying to satisfy both by providing 3 different ways to invoke many of the main screen commands, with a Midnight Commander-like interface for choosing which files and folders you wish to backup. The program offers advanced features such as email log backups, however it doesn't support back up to optical media (yet).
As for the Linux platform, one might say there is no real need for a complex backup tool, as a short . sh script that tars and zips to a specified mounted partition will suffice in most cases. However, if for some reason this doesn't seem enough for you (or if you just don't know how to make that simple script), a list of tested programs can be found here: http://www.linux.org/apps/all/Administration/Backup.html Bacula (http://www.bacula.org) in particular is an excellent tool for backing up files across a network.
Check out the author's website here: http://wysinnwyg.altervista.org/