Small businesses and one-man bands rarely have the time and IT expertise to implement a comprehensive backup and disaster recovery strategy, and consequently all too many run the risk of serious damage to their operations should trouble strike. Tape drives — the traditional medium for such tasks — have generally been too expensive and too slow for this end of the market. Fortunately, hard disks have become capacious and cheap enough in recent years to be a viable option for low-end backup/recovery duties. HP's StorageWorks RDX Removable Disk Backup System is a notable example, coming in at just £205 (ex. VAT) for the 160GB AJ766A model reviewed here.

Our review sample was the external USB 2.0 version, which comprises a robust rubber-clad docking unit and a chunky, shock-proof removable cartridge containing a 2.5in. SATA hard disk. The cartridges are rated to withstand a 1m drop onto concrete and are good for a minimum of 5,000 load/unload cycles in the docking station. Our unit had a 160GB cartridge, which costs £170 (ex. VAT) for additional units, but 320GB (£279) and 500GB (£409) cartridges are also available. According to HP, even higher capacity cartridges are planned over the next two years. The docking unit is also available as an internal 5.25in. USB drive or a rack-mount model for servers.

We installed the RDX on our self-built 3.2GHz Intel Core i7 testbed system running Windows 7 RC. It comes with two software CDs: one contains the install wizard, a diagnostic/firmware upgrade utility and documentation, while the other has HP's RDX Continuous Data Protection (CDP) Software.

When you insert a new cartridge, RDX Continuous Data Protection (CDP) Software asks whether it should be used for automated backups.

CDP claims to provide 'hands-free' backup: once installed and with a target cartridge identified, it backs up all of the partitions on your system and makes incremental backups automatically from then on. CDP also creates a system folder in Windows Explorer where you can view your backups and restore selected files. The RDX is also compatible with a range of third-party backup software such as HP Data Protector Express, CA BrightStor, ARCServe Backup and Symantec Backup Exec. Of course, if you want, you can also simply use the RDX as a drag-and-drop storage device in the same way you would a USB stick, for example.

RDX CDP creates a system folder in Windows Explorer where you can examine backed-up files and restore them by dragging and dropping.

HP claims a data transfer rate of 30MB/sec for the RDX. To test our unit's performance, we ran the Disk tests within Passmark Software's Performance Test 7.0 benchmark suite. The results were well below the rated speed — 13.6MB/sec for Sequential Read, 12.2MB/sec for Sequential Write and 2.7MB/sec for Random RW. More anecdotally, restoring a 446MB file from the CDP backup folder took 24 seconds, which represents a data transfer rate of 18.6MB/sec.

The HP StorageWorks RDX Removable Disk Backup System comes with a one year, next-day, parts-exchange, limited warranty with phone support for the duration of the warranty. HP's web site provides extensive array of documentation, FAQs, software and driver downloads and other information.

This is an excellent backup solution for small businesses, and more cost-effective than tape at this end of the market — by comparison, the external version of HP's StorageWorks DAT 160 USB Tape Drive costs £539 (ex. VAT), although additional 160GB tape cartridges cost just £30. The RDX's performance could be better, but that's our only real concern.