The operating-system wars are increasingly being fought on tablets. Google appears to be reserving Android 3.0, code-named Honeycomb, especially for tablet PCs. Vendors showing off Android tablets--many of which appeared behind glass--include Asus, Dell, Motorola, Lenovo, and Samsung. Windows 7 is also popping up on tablets, but Microsoft's announcement that Windows 8 will be ARM-compatible indicates that Redmond may have OS changes in store for future slates. The long-awaited BlackBerry PlayBook will run on an entirely different OS.