Microsoft did not respond to a request for comment on the Google announcement.

Analysts did note that Google must stick to the long, complex grind of developing an operating system if it wants to be successful in that business.

Rebecca Wettemann, an analyst at Nucleus Research, said that in recent months, Google has shut down or stopped supporting several products, including Google Video, Google Notebook, the Jaiku microblogging service and the Dodgeball mobile social network.

"They pick something up, get excited about it and work on it until they find another shiny new object they want to play with," Wettemann said. "My feeling is that Google needs to stop announcing things and instead execute on completing them."

Nonetheless, the Chrome OS plan has attracted the support of several top PC vendors, including Hewlett-Packard, Lenovo Group, Acer and Asustek Computer.