Chrome OS When Google first launched its Chrome Web browser, many of us immediately saw Chrome as Google's extension of an operating system.

Now, that prophecy is fulfilled with news of Google's plans to open-source the Chrome OS code later this year with view to have it available in the second half of 2010.

But immediately, this raises fundamental questions about what, exactly, defines an operating system, and what will distinguish Android, the open-source mobile OS spearheaded by Google, from Chrome OS.

I can't help but wonder if we'll look back on this news and think of it as the start of the next Great OS Wars.

Google Chrome 2.0 review

Google says its goal is to improve the user experience with computers - and clearly, that's possible given the laundry list of annoyances with today's PC-based experience.

Mobile is driving innovation, too: The iPhone, Google Android, and WebOS mobile OS experiences have already shown us the potential when hardware integrates with elegant and well-designed software.

While Microsoft Windows has competition in Apple's Mac OS X and Linux, the truth is that Windows has really been competing against itself.

Windows 7 review

Windows Vista review

Windows XP review

Sure, Mac OS X's evolution has put pressure on Microsoft, but PC users have routinely turned to either Windows XP or Windows Vista (reviled though it may be) for their computing needs.

Consider the netbook world: Mediocre Linux distributions installed on early netbooks had difficulty selling, because shoppers wanted the Windows environment on their netbook, not some merely functional, Linux-based Windows wannabe.

Fast forward to the introduction of Android. The Linux-based Android debuted just a few months after Apple introduced its sharp iPhone OS 2.0 with App Store support.

Chrome OS

And mobile OSes have been the hot topic ever since: When our US sister title most recently examined the mobile OS landscape, it noted that Apple's iPhone OS 3.0 edged out Palm's WebOS and Google's Android - for now.

It gained points for its smooth interface, ease of use, and its wide application support. Palm's WebOS also gets bonus points for its interface and strong ties into Web-based services, including Google's own calendar and email.

And Android gets plenty of attention, too: Its pretty-face design (though, WebOS and iPhone are prettier still) and interface makes it highly competitive with WebOS and iPhone OS 3.0, and its connectivity and integration with Google's Web services (calendar and e-mail, but not Google Docs) made me take notice when I reviewed the first Android phone to hit the market last autumn, the T-Mobile G1.

The key thing to remember is that even though these mobile operating systems are tied tightly with their handset hardware, they are not necessarily limited to smart phone handsets.

Rumours of a Google operating system based on Android have been circulating for a while now, and already we've seen reports of planned netbooks that will run Android (Acer's Aspire One is due in the autumn).

Google Chrome OS: Watch out Apple

In fact, smart phones are nothing more than low-powered, highly portable computers, often running ARM or similar processors - the same processors found in so-called smartbooks, and soon to be found in some netbooks, perhaps, as well.

The idea of an Android-based netbook OS is not new then, and makes the news of Google Chrome all the more unsurprising.

However, why Android? What's to stop WebOS for making a go of it on a larger, more powerful device than the Palm Pre? Why wouldn't Apple pipe its iPhone OS 3.0 (based on the same kernel as Mac OS X) to a tablet or other portable device?

Thus far, the sort of Google-to-Web integration we've seen from Android on smart phones, and from Chrome on the PC, just hasn't seemed all that unique.

For example, the current Chrome browser for Windows gives some insight into the blurring lines between desktop and Web browser. Chrome lets you create shortcuts on your Windows PC to any Web page or Web application, for example (this feature is not yet available in the Mac version of Chrome).

When Chrome first came out, this felt fresh. Now, however, I'm less impressed - Apple's iPhone OS 3.0 lets me do that, too, on my iPhone 3GS.