Net Results: It's long been known that the software and hardware industries ratchet ahead in a little two-step purchasing shuffle. The latest software versions are usually so complicated that they require new hardware to run acceptably, writes Danny O'Brien.

And it works the other way, too. The latest hardware often requires you to go out and buy the newest software to take advantage of it. The very first version of Windows prompted millions to buy new Intel 80386 machines to take advantage of its advanced features. Apple and Linux users regularly grit their teeth and graduate to the latest versions of their operating system, just to get that new phone or USB gadget working.

Half of that two-step isn't working so well these days.

Computers are still getting quicker - and cheaper. But it's been a long time since any new application has come along that's demanding enough to stop even the old, slow machines in their tracks. The most modern program on most people's PC is their Web browser. And that program, be it Internet Explorer, Opera, Safari or Mozilla, isn't, at heart, much more demanding than the first graphical browser, Mosaic, written for the top of 1994's PC range.

The spread of the Web browser prompted a massive re-investment in computer hardware in the mid-1990s, kick-starting the then moribund IT sector. In the last few years, there's been little comparable to that demand. The modern desktop PC - and increasingly laptops - look overpowered for what they're asked to do. The lament of Douglas Adams's creation, Marvin the Paranoid Android comes to mind: "Here I am, brain the size of a planet, and you want me to check your AOL mail."

Now to any computer owner that sounds just fine. We can, at last, keep last year's PCs longer than last autumn's fashions. But to the IT market, which depends on the repeat purchasing of machines and software, it's a recipe for despair. It needs a new and demanding piece of software soon. They need a killer app that everyone will want, even though it'll slow your current PC to a crawl.

And at last, in one of those curiously spontaneous moments of flocking together, it looks like the industry may have found it.

Here's the scenario. You have all this information: your email, all those Web pages you read, all those documents on your hard drive, all those hundreds of unfiled digital pictures. If you're a serious user of computers, you now have far more on your PC than you'll ever remember.

PC users spend more time peering around inside the cavernous gigabytes of their hard drives than they did in the most disorganised filing cabinets. The computer helps us store away so much about our lives, but does very little to help us find it. What PC users are begging for - or what many in the industry think they're begging for - is better searchability of their machines.

And this isn't searchability in the way the Net is searchable via Google or MSN.

Microsoft's new OS upgrade, code-named Longhorn, promises to put searching at the heart of your computer. The dozens of folders and directory metaphors that fill our hard drives will melt away, to be supplanted by a filing system that can be cross-referenced in any number of different ways. "Google's a very nice system," said Jim Allchin, the Microsoft executive in charge of Longhorn, "but compared to my vision, it's pathetic."

All of that, naturally, will take up a great deal of your computer's resources. Here's the good news (or bad, depending how you approach it) - Longhorn won't be here until 2005 at the earliest. So you'll have plenty of time to save up for that new PC. Or will you? I've spent the last few days playing with an application called Dashboard. It's got much humbler ambitions than Longhorn, but certainly bristles with potential in many of the same areas. Written by one of open source's singularly most prolific and enthusiastic young coders, Nat XXXXX, Dashboard may be the next killer app - or at least, a taste of what is to come.

Dashboard takes up a narrow horizontal strip of your screen. Specially adapted versions of your other applications - your mail client, Web browser, or even every key you type - constantly report to Dashboard what you're reading, typing, or surfing. Dashboard collates this data, hands it around to other applications to peer at, and puts up small nuggets of information about what these events - these clues - remind it of. You mention your brother in an email, Dashboard shows you the last few mails your brother sent you. Links to documents on your hard drive that also mention your brother quietly appear. Your brother's contact details appear. Surf a Website about Orlando Bloom, and other Web sites you've visited that mention the star scroll past.

It's a beautifully simple and passive application, and - except for a few academic projects over the last decade - quite unlike any app I've seen before. It's not ready to go yet: in the true open source style, Nat has opened it up for other programmers to fiddle with before he's even finished writing it. But already it has created a tremendous buzz - coders are retooling existing Linux applications to support it.

Even if Dashboard doesn't make the crossover to Windows, something like it, soon will. Nat started Dashboard as a side project. He doesn't like the idea of it being Linux or anyone's killer app: "I'd rather think of Dashboard as the Mosaic of information assistants," he says, referring to that early browser that inspired so many.

But perhaps there's another link to Mosaic. As I've been playing with Dashboard, I've noted that to do all the indexing, all the comparing, all the background remembering I want it to - I really need to go out and get a faster machine. Nat may not want to create a killer app. But he may end up bringing the IT industry back to life.