Product Reviews

Iomega sure likes removable storage. It enjoyed the many years when the Zip looked like the natural ubiquitous successor to the floppy disk, and since then it has tried to market the Jaz, Ditto and Clik brands with varying levels of success.

And now we have Rev 70GB, the second generation of its removable hard disk technology, so named because each disk holds 70GB of data, doubling the capacity of the original product launched two years ago.

Externally, little has changed with the drive into which the hard disk cartridges slot. It's finished in a darker grey, but is otherwise identical.

The ridge on the top near the front means you can't stack the drives, but it's vital as a grip given how stiff the cartridges are to insert. Iomega will shortly release an update to its eight-cartridge Rev Loader unit, so if you want the ability to have multiple or rotating cartridges, you can wait for that. An Atapi version is also available for fitting inside tower desktops.

If nothing else, the technology at work here is spectacular. Just think: hard disks are traditionally manufactured in superclean conditions to minimise contamination; a smoke particle is big enough to disrupt the connection between hard disk platters and the read/write heads 'flying' a microscopic distance above their surface. And here, the platters are held in the cartridge, while the read/write heads are part of the drive itself. The potential for contamination is immense, but Iomega works hard to contend with this.

Its approach - characterised by the mantra 'start clean, stay clean, manage the remainder' - ensures the best possible starting point. The drive motors are built into the cartridges not the drive, so there's no gap in the cartridge where a drive-held motor unit could engage with the platters.

The drive unit itself is constructed so that the air pressure on the inside matches the ambient pressure,

The cartridge's swinging door system that allows the read/write heads access to the platters is an improvement on earlier sliding-door systems, which can generate debris during operation, but it's not difficult to open it manually by simply releasing a catch. While only someone hellbent on compromising data integrity would try to peer inside a cartridge, we'd rather see a system that made it impossible - or at least very difficult - to open the cartridges outside the drive; exposing the platters to a normal office environment can quickly lead to the accumulation of debris.

But at least if this does happen, a number of filtration, error correction and cleaning technologies are in place to cope with any contamination.

The advantage of all this is reliability; Iomega claims 30-year shelf life for your data - which may not sound like much, but the Mac has only been around for 22 years - and the cartridges themselves appear sturdy. It's impossible to test these claims fully, however.

The carts use UDF - the same format as DVDs - but the Mac's support for UDF is incomplete. During installation, therefore, some kernel extensions are copied to your Mac; these have caused no problems so far, but such low-level tinkering did worry us just a little.

The software allows you to reformat disks as UDF - although you can use Disk Utility to reformat to HFS+ if you like, allowing you to use Apple's own Backup tool instead of the bundled Retrospect Express - and also offers some cumbersome password protection abilities.

It helps to think of Rev as the successor to tape, rather than hard disks per se. For many of us, external hard disks - or server/network-based hard disks - are a more convenient and cheaper backup solution, but for small to medium workgroups looking to implement a rolling, rotating backup regime, Rev provides a faster, easier alternative to tape. The unit (£309 with one 70GB cart) and media (£170 for a five-pack) are too expensive for what they are, but neither break the bank, and the system has an effectively limitless capacity.