Windows vs. Chrome OS, so it begins, or at least it’s about to. At the end of the past week, Google started sending out invitations to a Chrome team event on December 7th, 2010, in San Francisco.

The promise from the Mountain View-based search giant is that some exciting news about Chrome will be made public. No other details were offered, but the general consensus among various third-party sources seems to be that the event is related to Chrome OS.

Google’s open source Linux-based operating system has been cooking for some time now, and the company now seems closer than ever to place a foothold in Windows territory.

Speculation indicates that Google might ready a Beta preview of Chrome OS which would ship on a netbook offered to developers.However, this is not the actual general availability deadline of Chrome OS, which was postponed to 2011, with Google refusing to detail the reasons of the delay. Chrome OS was initially planned for availability by the end of 2010.

And Windows is about to get a new rival. Windows 7 at least, since, despite still being present on the market, Windows XP and Windows Vista are largely irrelevant in terms of new sales.

Just a few years ago, Google was launching the Chrome browser, and now the company is extremely close to the 10% mark of the market.

Granted the OS market is not as crowded as the browser one, and Windows is in a far more dominant position than Internet Explorer was when Google’s browser shipped, but if the success of Chrome is any indication, Microsoft needs to brace for impact.

Chrome OS comes with a new approach to the classic operating system model. There’s very little local storage, and there are no application programming interfaces (APIs) to support applications running locally.

Instead, Chrome OS is built for the Cloud, and is browser-centric, with the Chrome browser at the core. The user data, settings, content, applications sit in Google’s servers rather than being stored locally.

Meanwhile, Windows 7 still has the same Cloud connections as its predecessors, largely related to the Windows Live Essentials suite.

Microsoft does have the chance to push Windows 8 into the Cloud, linking it with Windows Azure, but there’s no telling whether the Redmond company will actually do it, or wait for the next version of Windows, after Windows 7’s successor.

Meanwhile, Google is extremely close to have the operating system rendered all but useless, and shift the focus entirely to the web.

Estimates indicate that Chrome OS will be available on netbooks in early 2011, but a release date has yet to be disclosed.

What’s interesting is that Chrome OS was created in a time when netbooks were extremely hot, which is no longer the case.

Consumers seem to prefer tablets / slates to netbooks more and more, especially for media consumption scenarios, and in this regard, Chrome OS might just have betted on a losing horse, at least in the long run.

And the operating system cannot simply be transitioned to tablets, since it’s not sufficiently touch-centric, but tailored to machines with keyboards instead.

Windows 7 dominates the netbook market for the time being, although it will take a while before slates sporting the OS will gain traction, and not until 2011 at the latest, even according to Microsoft estimates.

As far as netbooks are concerned, the Redmond company has won the OS war with Linux, and it did it with XP, before Windows 7 was launched.

Now Chrome OS comes to challenge Windows’ dominance, the shadow of Linux is still in the background, and it’s time for Microsoft to take on a new rival.