Back in the days of OS 9, if your Mac had start-up disk problems, creating a resue disk was easy. OS X changed all that, making it altogether trickier. Thankfully, Micromat has charged to the rescue with TechTool Protogo.

This automates the process of creating an emergency rescue disk using anything you might have to hand - a hard drive, an old iPod or even a Flash drive - and reduces the whole process to more or less a few mouse clicks.

To use Protogo, just plug in your removable media and launch. It will offer you a variety of pre-built configurations for an emergency disk. The most basic is a single partition that will start up any Tiger-capable Mac, whether it has a PowerPC or an Intel chip.

This partition will boast Micromat's TechTool and DiskStudio utilities, as well as OS X's Console, Disk Utility, Terminal and System Profiler. You won't have access to the Finder with this configuration and the version of OS X installed will be 10.4.8, from a disk image stored within the Protogo bundle.

But other configurations offer more, each with increasing disk space requirements. You can add Finder support; set up an OS 9 partition that has Disk First Aid, TechTool Pro 3.1.1 and Drive Setup installed; create a partition based on a working OS X installation; and add applications that you'd like to be included on the drive. You can also create custom configurations.

Once you've picked and customised a profile, click the Build TechTool Protogo Device button; Protogo asks if you'd like to reformat the disk, then wait as it copies over the necessary files. You can then connect the drive to a distressed Mac, restart the Mac in target-disk mode and boot off the drive. The Micromat Launcher starts automatically, giving you quick and easy access to any utilities you chose to include earlier.

In practice, the Universal Profile works as claimed. After reformatting an old 5GB, first- generation iPod with that profile, we were able to use it to repair both an Intel-based iMac and a PowerPC PowerBook. The iPod actually seemed more reliable as an external device than before we'd reformatted it. Protogo pros and cons Protogo pretty much does what it says on the box.

Its relatively high price isn't that steep when you consider that TechTool Pro and DiskStudio are part of the package. If you're worried that the Protogo disk image will become outdated as you buy new Macs, you can subscribe to an annual update scheme as well, but this will be unnecessary for the average user.

The program does have a couple of flaws. The first is that those unhappy Macs that can't run Tiger are left out in the cold, unless you can fashion a working pre-10.4 installation on another drive. OS 9 booting can help a little. There's also the assumption that any extra tool you need will exist purely as an application and not need other files.

Some support for slipstreaming apps that use standard OS X installers into the emergency disk would be helpful. However, with DiskWarrior, Data Rescue II and other utility apps shipping as standalone applications, this is no great problem, and both TechTool and DiskStudio are fine apps in their own right. Most people will find these sufficient.

If you have an array of Macs that you need to support and are fed up of manually creating emergency disks, get Protogo.