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 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.
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.
And mobile OSes have been the hot topic ever since: When our US sister title PCWorld.com 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).
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.
Chrome OS vs Android
Before I can the value of a Google-owned, Chrome-based operating system, I'd have to understand what it offers to me as a user that will be different from any of the options available to me today.
In Google's blog posting announcing Chrome OS, the company notes "Google Chrome OS is a new project, separate from Android.
Android was designed from the beginning to work across a variety of devices from phones to set-top boxes to netbooks.
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. While there are areas where Google Chrome OS and Android overlap, we believe choice will drive innovation for the benefit of everyone, including Google."
I spend most of my time on the Web, but the above, admittedly early, description does nothing to help differentiate Android from Chrome OS.
Indeed, I question the language: Android users are more likely than anyone to be heavily tied into the Web, given the always-on connectivity on mobile devices.
So, what, exactly, might be the difference between Android and Chrome OS, and how might that challenge Windows?
Presumably, for Chrome OS to truly be a competitive option to Windows 7 on full-blown laptop and desktop configurations, you'd need for Chrome to have wide device driver support for components and peripherals - a sandbox Google hasn't really played in before.
Without such device support, Google could run into issues with far-flung devices such as printers or graphics cards. The company might even need Windows virtualization for Chrome OS: After all, users who rely on Windows apps might still need to access those apps on any Google-based device.
And speaking of apps, while Google notes that apps for Chrome OS would work on any other browser, it still opens questions about what the advantage of a browser-based app would be to begin with.
Look at what happened with Apple's attempt at browser-based apps: It fizzled and was completely forgotten once iPhone OS 2.0 hit last summer with full support for locally stored applications.
Chrome OS may have an early advantage that the iPhone lacked, in that HTML 5 has support for locally stored data for Web apps; however, this yet-to-be implemented approach still might not help you if you're at 38,000 feet over Lincoln, Nebraska, and don't have any Web access.
Another statement from Google got my attention: "We hear a lot from our users and their message is clear - computers need to get better. People want to get to their email instantly, without wasting time waiting for their computers to boot and browsers to start up.
"They want their computers to always run as fast as when they first bought them. They want their data to be accessible to them wherever they are and not have to worry about losing their computer or forgetting to back up files.
"Even more importantly, they don't want to spend hours configuring their computers to work with every new piece of hardware, or have to worry about constant software updates."
These points are true, especially the one about software updates. But I don't know anyone who'll want to only store data in the cloud; nor do I know anyone who would use a device as a primary computer if it won't work with the host of devices one might attach.
And to assume that a new Google OS won't require constant software updates is a bit presumptive: Google has pushed out Android updates big and small; and Apple is continually updating is iPhone OS 3.0.
I do think that Android and Chrome OS can have a place on devices, and I believe these will give competing operating systems, mobile or otherwise, a run for their money - if, and only if they have apps that provide cross-platform compatibility with the Windows universe.
But I'm not convinced that even Google can challenge Windows (or Mac OS X for that matter) on netbooks or larger devices.
The device and software compatibility issues loom large here. And until Google can sell users on the advantages of its Chrome OS over other competitive options, I think the company could have an uphill struggle for carving out the niche it clearly has targeted with Android and Chrome on mobile and non-PC devices.
Microsoft Windows 7, Google Chrome OS, the first netbook with Android - these are just a few of the interlinked developments we have to look forward to in the third quarter of the year. It's going to be a busy autumn, after all.