Windows 8 is more than just the most radical makeover in the quarter-century history of Microsoft's operating system. It's also creating a new class of mutant personal computers.
Nowhere is this clearer than in the laptop segment, where the long-dominant clamshell design is yielding to new forms: computers that bend, tilt and swivel, with touch screens that are clearly inspired by, even if they don't directly compete with, handheld tablets like Apple's iPad.
With that in mind, I've been trying several of these new convertible-tablet hybrids. All are of the "Ultrabook" category: They run on Intel chips, are thin and light as these things go, have no DVD drives and use solid-state flash memory in place of a traditional hard disk.
Of the first wave, my favorite so far is Lenovo's IdeaPad Yoga, which as its name implies can be folded into all sorts of interesting positions.
At first glance, the Yoga, which starts at $999, looks like a fairly standard clamshell, .67 inch thick and weighing 3.4 pounds. It's solidly built, with hinges strong enough to keep the 13.3-inch screen from flopping around -- one of my laptop pet peeves.
If you use the screen only in that position, though, you're missing the whole point.
Fold the Yoga over and it becomes a touchscreen tablet -- too heavy to hold for long, but useful to watch a video or take advantage of Windows 8's full-screen applications. (The keyboard, which faces out, is automatically disabled to avoid errant presses.)
You can also stand the screen up, using the inverted keyboard as a base, or prop it up like a tent.
The major drawback, one that afflicts its competitors as well, is the minimal storage capacity -- or, more specifically, the amount of it claimed by Windows 8 system files. Fewer than half the 128 gigabytes on my test machine were available for my own applications, files and content. The least expensive model with a more plausible 256 GB, available in the U.S. only through Best Buy, is $1,400.
Sony devices these days range in design from straightforward to what-were-they-thinking eccentricity. The Duo 11, which starts at $1,200, falls into the latter category.
At rest, the Duo is a tablet .71 of an inch thick. At 2.87 pounds, it is more manageable than the Yoga. But it becomes considerably less satisfying when, after fumbling around to figure out how to open it, you lift and slide the 11.6-inch touch screen to expose the keyboard.
The problem is the design, which means that the propped-up screen covers almost half the base. The result is a cramped keyboard with no place to rest your palms, nor even a track pad. Instead, there's a tiny round pointing device wedged in between the G, H and B keys.
It makes for a thoroughly unpleasant typing experience. While Sony tries to mitigate the input problems by including a stylus, there's no place on the Duo 11 to store it.
In general, the Duo 11 is much better for consuming content than for producing it: The high-resolution screen makes viewing high-definition videos in tablet mode a pleasure. But my test unit was plagued by a balky accelerometer that sometimes took an inordinate amount of time to reorient the screen when I flipped it from landscape to portrait.
Over the years, Toshiba has developed a reputation for solid, decidedly un-flashy, laptops. Windows 8 has given it the opportunity to finally break out, and Toshiba has seized the moment to deliver the Satellite U925t, a convertible starting at $1,150 that is -- sorry -- solid and decidedly un-flashy.
At 3.4 pounds, the Satellite is actually a little lighter and has a smaller footprint than the Yoga. But it feels bulkier, owing to its slightly greater thickness and less elegant design.
Like the Sony, and unlike the Lenovo, the Toshiba's screen is always exposed, meaning that you may want some sort of sleeve or cover to protect it from dirt when not in use.
Also like the Sony, you slide the screen up to put the Satellite into laptop mode. But at least you have an adequately sized keyboard, a touchpad and a little extra space for your wrists. You also have a larger screen -- 12.5 inches -- though its 1366-by-768-pixel display lags behind both the Duo 11 and Yoga. And while long battery life isn't an outstanding characteristic of this entire category, the Satellite was marginally better than either of the others.
The coming months will see the arrival of scores of similar Windows hybrids, most notably including a new, more powerful version of Microsoft's Surface. Whether these new devices can stave off the PC's long, slow decline remains to be seen, but in the meantime they are introducing some welcome novelty into the market.