Microsoft links PCs to mobile computing

1,000 devices are OK'd for revamped operating system

NEW YORK -- Can't decide whether you want a PC or a tablet? Now you won't have to. With the release of Windows 8, computer makers are blurring the boundaries with devices that mash keyboards and touch screens together in different ways.

Some configurations are new, though others have appeared and disappeared on the market since at least 2002, when Microsoft released Windows XP Tablet PC Edition.

Microsoft says it has certified 1,000 devices for use with Windows 8 and its sibling operating system, Windows RT. The two systems look the same, but under the hood, they're quite different.

Windows RT runs only on machines with the type of lower-energy, phone-style chips used in iPad and Kindle tablets. That makes for cheap, thin and light devices with very long battery lives -- more than 10 hours. But those devices won't run any programs written for other versions of Windows. In fact, they can run only applications downloaded directly from Microsoft's online store, in a setup borrowed from Apple and its iPhone.

Windows RT devices have limited ability to connect to peripherals, such as scanners and printers. Here's a selection of the devices that went on sale Friday or will hit stores over the next few months:

Convertibles -- The Transformers of the bunch, they run on Intel chips and may look like staid laptops, but one way or another, they convert into tablets.

Toshiba U925t -- To convert this laptop into a tablet, push the 12.5-inch screen back, then slide it over the keyboard with the display facing out. Available now for $1,150.

Sony Vaio Duo 11 -- Similar to the Toshiba but smaller, the folding mechanism on this model leaves no room for adjusting the angle of the screen. There's no room for a touchpad, either. Instead, there's a touch-sensitive "nub" in the middle of the keyboard that lets you guide the cursor. The 11.6-inch screen also works with a stylus. Available now starting at $1,100.

Lenovo ThinkPad Edge Twist -- Like all ThinkPads, it is a business-focused machine. This one incorporates a mechanism that's been in use in tablets for a decade: The 12.5-inch screen connects to the base with a swiveling hinge. Flip the screen around, then fold it over the keyboard to turn it into a tablet. Available now starting at $849.

Dell XPS 12 -- The 12.5-inch screen on this laptop is hinged inside its frame. It can be flipped around so the screen faces away from you, then folded over the keyboard for tablet mode. Sound original? Dell has actually tried this design before, for a 2010 laptop. Starts at $1,200, with an estimated ship date of Nov. 15.

Lenovo Yoga 11 -- This 11.6-inch screen goes back -- way back. You can push it so far back that it's flat with the underside of the laptop. Now you have a tablet with a screen on one side and a keyboard on the other. Luckily, the keyboard turns off when you fold the screen back, so you can hold the device. Unlike most convertibles, which run on standard Intel chips, this one uses Windows RT and a processor from Nvidia. Available in December for $799.

Windows 8 tablets -- These slates run Intel chips and regular Windows software. Computer makers are hoping they'll find a home among businesses that need employees to access their work applications while commuting or traveling, but they're also hoping to entice consumers.

Samsung ATIV Smart PC 500T -- This tablet, with an 11.6-inch screen, looks much like a small laptop when docked into a keyboard base. The combination also folds up just like a laptop. Available now for $650. The keyboard costs another $100 and contains an additional battery to extend the workday.

Lenovo IdeaTab Lynx -- Similar to the Samsung model, the Lynx goes on sale in December for $599. The keyboard will cost another $149.

Hewlett-Packard ElitePad 900 -- A 10-inch tablet aimed squarely at business users, the ElitePad is paired with "Smart Jackets" that extend its capabilities with extra battery life, a keyboard, a stylus or memory-card slots. Available in January at an as-yet undisclosed price.

Hewlett-Packard Envy X2 -- The consumer equivalent of the ElitePad is slightly larger, with an 11.6-inch screen, but weighs the same: 1.5 pounds. A keyboard dock with an extra battery doubles the weight and turns it into a small laptop. Launches this holiday season. HP hasn't said what it will cost.

Windows RT tablets -- Though they lack the ability to run standard Windows programs, these light tablets include a version of the Office software suite for free.

Microsoft Surface -- Yes, Microsoft is diving into the hardware business, making its own tablets and competing with its customers, the computer makers. The Surface will have a screen that measures 10.6 inches diagonally, slightly larger than the iPad's. Available now starting at $499. Keyboard cover is $100 extra with base model.