Fujitsu's LifeBook U810--an ultrasmall convertible tablet and laptop--is a 1.5-pound, palm-size Windows Vista system whose lilliputian dimensions are both its strength and its weakness. By trying to cram in most of the features you'd expect in a larger laptop, Fujitsu satisfies consumers' pleas for a convenient, portable Windows Vista system. But consolidating everything into a 6.5-by-5-by-1-inch chassis sharply reduces the functionality and productivity that the U810 can deliver.

Armed with an 800-MHz Intel A110 CPU and 1GB of RAM, the unit sports a smallish 40GB hard drive, Wi-Fi, Bluetooth, a biometric fingerprint reader, and Windows Vista Business Edition. It has one USB port and both an SD Card slot and a CompactFlash slot, along with a double-duty port inconveniently located below the minuscule spacebar; the port works with the included ethernet cable or a port replicator (optional, $80).

WorldBench 6 Beta 2 performance was poor: The U810 received a score of 19--the lowest mark we've seen to date. Battery life was fairly impressive, though, at 4 hours, 30 minutes in our tests. In my informal trials, streaming video was on occasion jerky.

The U810's clamshell notebook screen swivels to become a tablet that's light enough and small enough to hold in your hands, with a passive touch screen on which you can make handwritten notes. A dedicated button atop the screen lets you toggle the tablet from the standard landscape layout to an easier-to-use portrait format. Alas, the 5.6-inch screen has a native resolution of 1024 by 600. Even after I switched to a mode intended to make the text larger and more readable, I thought I needed to put on my eyeglasses--except I was already wearing them.

Fujitsu throws in a Windows XP disc for an OS swap; we recommend using it, since Vista is optimized for more-powerful systems. But you'll have to buy an external USB CD/DVD drive to load it; Fujitsu sells one for $149.

The cramped keyboard will not work for touch typists, but the ability to use the included stylus or your finger on the touch screen partly compensates for the keyboard.

So who is the target audience for the LifeBook U810? People with Superman vision, really small fingers, and plenty of patience.

--Michael S. Lasky