I received an emergency call from a friend last week. About six months before, his Powerbook hard drive became severely corrupted. I recovered what data I could, but only saved about 35 per cent. The drive was still usable, but he had allowed it to become too full and for a few months it was writing over files that he needed to operate his computer. Word to the wise - do not let your computer hard drive get more than 80 per cent full. Anyhow, the emergency call came when he discovered that he needed some e-mails for evidence in litigation his company was undertaking. The missing communication had suddenly become quite valuable. The original hard drive now lived in one of those after-market firewire enclosures that make any disk portable. He had reformatted it, but fortunately he had not used it as planned - as a backup. I had originally used a beta version of Prosoft Engineering's Data Rescue X (US$89, www.prosofteng.com/products/data_rescue.php ). Since the programme had been dramatically upgraded, I thought I would give it another try. Well, it turns out that I have one lucky friend. I was able to recover 90 per cent of the old drive, including the precious e-mail. There is no need for such nerve wracking - and potentially catastrophic - experiences. A simple backup plan executed in a timely manner would have avoided a lot of heartache. Backing up data has changed since the introduction of OS X. In the days of OS 9, Retrospect was the answer when it came to backing and recovering files. When OS 10 arrived on the scene, Retrospect became buggy and unreliable, often presenting users with corrupt archive files and disappointment. A number of Mac shareware developers jumped into the market with partial solutions, but there was no solution for the Mac backup as extensive and complete as the Retrospect system. That is, at least, until a combination of high quality shareware apps evolved. A weblog created by Matt Henderson lists the tools and procedures, as well as the capability of each tool ( http://matt . makalumedia.com/index.html#id= 2005-08-07-Ardales&num=1). The log describes how four inexpensive shareware apps can provide everything you need in a backup toolset. First you use Qdea's Synchronize X Pro (US$99.95, http://qdea.com/pages/ pages-sprox/sprox1.html) to create a mirror (an exact bootable duplicate) of your main hard drive - either on a sister drive internally or on a removable hard drive. The programme will automatically duplicate all the work you complete each day on the mirrored drive. If your main drive fails, you need only restart from the backup and you will have only lost one day's work. The second app you need is Michael Tsai's DropDMG (US$15, http://c-command.com ) to automatically archive files to a third drive and/or to a CD or DVD. This is set up to make a copy of every file on your mirror drive that is changed. If you alter or delete a document, the original and the new version will be automatically archived to the assigned disk. When the file of archives is large enough to fill a CD or DVD (when compressed), it will notify you. You can then burn a copy that can be used for a remote backup protection in the event of burglary, fire or other local hazard. The third application is Skytag's File Buddy (US$39.95, www.skytag.com/file buddy/index.html), which automatically renames files by date or number. When you archive a contract and then modify it, the programme will give the new version a recognisable name such as Acme contract 12/13/02 - the last date edited. And finally, CDFinder (US$30, www.cdfinder.de ) for cataloguing your drives and disks. CDFinder is an exceptionally powerful catalogue/search tool that also works with Windows drives. For cataloguing your disks, Panther's (10.4) built-in Spotlight cataloguing and search tool is great and it is free. SuperDuper! (US$19.95, www.shirt-pocket.com/SuperDuper/SuperDuper Description.html) will do the mirroring necessary to get you a bootable drive. A great app for creating a mirrored bootable drive is Prosoft Engineering's Data Backup (US$59, http://prosofteng . com/products/data_backup_info.php). It is solid and dependable and has a number of features that allow it to replace both DropDMG and Synchronize X Pro.