Google released Chrome OS as open source today. It did not, however, release a beta of the operating system for users, and said that hobbyists who would want to install it on their existing netbook or other hardware were out of luck.

However, developers can compile the source code and run Chrome OS in a virtual machine to test Web app compatibility, Google said.

Analysts note the with Chrome OS's release to developers today, but the rival OS won't be available on new netbooks for another year -- and Microsoft seized upon that fact today.

"From what was shared, it appears to be in the early stages of development," a Microsoft spokeswoman said via e-mail.

"From our perspective, however, our customers are already voicing their approval of the way Windows 7 just works -- across the Web and on the desktop, and on all sizes and types of PCs -- as we've sold of any other operating system over a comparable time," the spokeswoman said.