Because Chrome OS runs exclusively on , it boots extremely quickly. The early build we played with took as little as 7 seconds to reach a login screen, and then snapped almost instantly into the browser.

Unlike traditional operating systems, Chrome OS offers few controls that you can't already find in Google's Chrome Web browser. The most significant difference is the Chrome icon in the upper-left corner, which reveals a list of bookmarked Web apps. It's as close as Chrome OS gets to installing software. While the inability to install apps as Windows does can be a limitation, it's also a safeguard against viruses and malware: If apps can't install, neither can Trojan horses and other nasty bits of code.

Like the Chrome Web browser, Chrome OS is tab-based. However, to keep your favorite Web apps handy at login, the OS gives you the option to pin tabs to the left side of the tab bar. Once pinned, a tab remains in the same location every time you log on, so it's always exactly where you left it.

Apart from a battery icon, a clock, and a network monitor in the upper-right corner, the operating system is identical to the existing Chrome browser for Windows. The whole idea is simplicity, and that's exactly what you get.

No Chrome OS devices have yet debuted on the market, and none are expected before the second half of 2010. Acer has declared that it will be among the first manufacturers--if not the very first--to . Meanwhile, Chrome OS already has some competition from the FusionGarage , a 12.1-inch tablet device running a similar browser-oriented OS.