Google has announce that it is developing an operating system for personal computers based on its Chrome browser.
The move marks Google's most direct challenge yet to Microsoft, whose Windows OS is the world's most widely used operating system.
Google made the announcement on its blog and said the Google Chrome OS would be available in the second half of next year.
"Google Chrome OS is an open source, lightweight operating system that will initially be targeted at netbooks," Google said in its announcement.
"Because we're already talking to partners about the project, and we'll soon be working with the open source community, we wanted to share our vision now so everyone understands what we are trying to achieve.
Google says the new Chrome OS will be distinct from its Android OS, which designed to work across a variety of devices from phones to set-top boxes to netbooks.
The first netbooks using the Android OS are expected to hit the market later this year.
"Google Chrome OS is being created for people who spend most of their time on the web, and is being designed to power computers ranging from small netbooks to full-size desktop systems," Google says.
"While there are areas where Google Chrome OS and Android overlap, we believe choice will drive innovation for the benefit of everyone, including Google."