Sparrow's second rule of computing is: "Whatever size of hard drive you buy... it will never be big enough."

Now, that's fine and not really a huge problem if you're talking about a desktop computer. You can easily upgrade a desktop hard drive in minutes. However, if you've bought yourself an iBook or PowerBook then upgrading the storage is a horrendously fiddly prospect. A better option is to buy some extra storage space by investing in a portable external hard drive from the likes of LaCie.

LaCie's P2 range of portable drives is the ideal solution for extending storage on a laptop. There's a choice of USB or FireWire interfaces and sizes go up to 80GB. Having a choice of ports makes cross-platform data transfer between Macs and PCs much easier.

Designed by FA Porsche, this dinky little pewter drive is small enough to slip into a jacket pocket or a compartment of a laptop bag. Performance is as good as can be expected from a 2.5-inch laptop drive, and the power required is drawn from the host FireWire port.

If you have USB ports that are beefy enough then you can also power the drive through those. If your USB ports aren't up to the job, then LaCie has supplied an auxiliary power line that can draw power from a USB port. This is also essential if you only have a four-pin FireWire port on a PC.

And so we move to the all-important matter of hard-drive performance. Whatever the specifications say... don't ever let anyone tell you that a USB 2.0 Hi-Speed port is faster than a FireWire 400 one.

On paper that might be the case but, as expected, our test on this drive showed that a sample file of 414MB of data transferred in just 18.9 seconds over FireWire and a sluggish 29.5 seconds via the nominally faster USB 2.0. Still, it's nice to have the choice of interfaces if you need to ferry data back and forth between different types of computer. Mark Sparrow