Following a slew of new netbook and tablet PC announcements at Computex 2010 -- and some rumblings about Windows' security -- Google has come forward with an update on its web-centric operating system for portable devices. Though still light on details, speaking at the Computex cloud computing forum yesterday, Google's VP of product management Sundar Pichai confirmed Chrome OS will be on the market in the fourth quarter of 2010.

The statement pushes back earlier rumors of a third-quarter launch, as Google continues to work closely with hardware partners to deliver clamshell devices with touch-pads, keyboards and screens between 10 and 12 inches across. At least initially this will be the focus. It isn't clear whether Chrome OS will also be ready for tablets when it launches. So far we've seen a few Android tablet prototypes being announced, but the jury is still out regarding which platform will work best in this market -- my guess is Google will stick with Android for touch-centric devices.

Announced nearly a year ago, Chrome OS is a lightweight operating system built around Google's Chrome browser. Like other Linux-based platforms, it will be available for free, allowing hardware vendors to avoid licensing costs. A big part of Google's focus is on speed, and as such startup times, including access to the web, should take seconds rather than the minute or longer that most Windows users endure. The cloud-based design should provide quick access to Google's suite of online applications, in addition to the Chrome Web Store which will launch alongside the operating system.