Windows RT

Microsoft designed Windows RT to work on devices with ARM-based processors (Windows 8 only works on computers with Intel chips). It looks like Windows 8's tile interface, and supports only a few desktop applications -- all other software must be in app form.

A PC OS for a Post PC World

There are two main layouts for Windows 8 -- the desktop and the tiled Windows 8 interface formerly known as Metro. The desktop environment will look somewhat familiar to anyone who has used a Windows-based computer over the last few years. You can create shortcuts to applications on the desktop. Clicking an icon will launch the respective program.

But the big news is the tiled interface. In a dramatic departure from traditional computer-OS design, this interface looks like it belongs on a tablet or smartphone. That's no accident. Recent trends show a decline in PC sales as customers turn their attention to mobile devices [source: Tyson]. But while we've seen big improvements in mobile designs and capabilities, there are still some types of software that work best on a full PC.

Windows 8 bridges the gap between PC and mobile operating systems. Microsoft optimized Windows 8's interface to work with touch-screen devices and displays. As mobile devices become more sophisticated, they could potentially replace PCs entirely. By creating an operating system that can work across platforms, Microsoft is attempting to cater to all customers.

If you have a touch-capable device or display, you can navigate Windows 8 with touch gestures. Tapping on a tile will open a corresponding application. Swiping the screen will let you navigate through apps or pull up the Charms menu from the edge of the screen. Microsoft places popular tools in the Charms menu, such as the search interface.

If you don't have a touch-capable device, you can still use the tiled interface with a mouse and keyboard. Instead of activating special commands with gestures, you have to place your cursor in one of several activation points to pull up particular menus or commands. You can use a scroll bar at the base of the screen to navigate left and right through the tiles.

Those tiles aren't just icons that will launch a program. Microsoft allows app developers to deliver information through tiles even when an app isn't active. The company calls the feature "live tiles." A live tile can display notifications relevant to the app.