Small devices and high-density storage are converging in spectacular ways. One of Apple's latest iPods carries 60 GB, enough for all your work files and thousands of digital photos and songs as well. Watch as next-generation phones begin to incorporate equally mammoth storage capabilities.

If you're tired of lugging a bulky laptop through airports, instead you can now use a hand-held device from Palm or HP. Drop in a 2 GB storage card and the main limitation is screen size, not access to your data. Or leave out the screen altogether. My son carries a gigabyte of data around with him on his keychain in the form of a tiny USB drive. He can plug it in anywhere to get at his files.

So taking your work with you isn't the issue. What would be nice is to carry work and computer in the same tiny space, without the limitations of miniature screens. Researchers at IBM may have found a way to do just that.

Their SoulPad (a wonderful extension of the honored ThinkPad moniker) aims to put a virtual computer on a USB key, activating it whenever you plug it into a host machine.

This is a long-standing goal among computer developers. In fact, the U3 Consortium, made up of manufacturers of USB flash drives looking to move beyond simple storage, has developed technical specifications that allow you to carry all your programs and settings on a USB device in your pocket. But SoulPad goes a step further; when you plug it in, it restores your computing environment down to the level of the windows you left open in your last session.

The SoulPad work so far has all been done at IBM's T.J. Watson Research Center in Yorktown Heights, N.Y.

Here's how SoulPad will work once it becomes commercially available. If I'm working at my desk and save my work to SoulPad, the device saves everything from the programs I'm running to all my data (including browser cookies, personal settings and bookmarks). As opposed to hardware, these represent the "soul" of the computer. Now I can unplug the device to take my PC experience anywhere.

Wherever I travel, I can now plug SoulPad into any machine's USB or FireWire port to find my last computing session restored. All my information is available, my applications are identical down to the tiniest personal tweak, and when I'm finished on the machine, I can save everything back to SoulPad, which will leave nothing behind on the host machine but will preserve all my work.

SoulPad works its magic by containing its own operating system, a version of Linux called Knoppix that recognizes and configures the host computer's components. Layering in encryption to keep personal data secure, the software then transfers control to a built-in "virtual" machine that contains the computing environment on the user's desktop. SoulPad uses the highly regarded VMware to create its virtual PC, but its methods mean it runs slower than a standard computer, taking roughly two minutes to boot up.

Say goodbye to your laptop? Not yet. The product is still in testing, with some issues -- like graphics configuration -- still under development. But imagine SoulPad in finished form licensed to hardware manufacturers. I can see something like this in smart phones; heck, Nokia's N91 phone already includes a 4 GB hard disk, with larger storage options clearly in sight.

In other words, rather than carrying a laptop to have access to your data, you'll have a wide range of choices, none of which will need to be as large as a conventional computer. Those of us who don't like to travel with computing devices should have no trouble adapting to a keychain drive that carries all our work, and carrying an always available PC backup isn't a bad outcome, either.