Developed at IBM Japan: The PC Core System.

Still at the prototype stage, it's a tiny (16 x 8.2 x 2.2cm, 6.4 x 3.3 x 0.9in) PC containing a 1GHz Transmeta CPU, up to 512MB of RAM and a 20 gig hard drive.

The idea is that insteead of carrying a laptop, or storage devices you carry around your whole PC, and simply plug it into available base units as needed. I imagine that base units could also be portable (like a laptop) as welkl as having a more tradititional desktop formfactor - or for that matter, any sort of base unit, like set-top (great for motel rooms) or bedside (small screen with MP3 player alarmclock function) should be viable.

Once your entire operating environment moves with you, the possibilities grow enormously.

IBM debuts pocket-sized PC @ The Register.