Google has fully unveiled the cloud-based Google Chrome OS, but stopped short of unveiling any notebooks, scuppering hopes that it would be available before Christmas.

Acer and Samsung will bring the first Chrome notebooks to market in the middle of 2011, but until then only a limited amount of users, under a Chrome pilot program, will be able to test the OS.

Google has admitted that it was "not quite there yet," in terms of completing the operating system so devices are not yet ready to ship. All things considered, that's a bit of a letdown.

Full demo

Despite the lack of hardware, Google has shown-off the gorgeous web-centric Chrome OS in all its glory and it looks magnificent.

The Big G took the opportunity to showcase 'instant boot' with a notebook starting up in 60 seconds and resuming from stand-by mode to get back online instantly.

The OS demo also showcased easy syncing across devices, seamless sharing with friends and family and a friend login mode to allow others to privately and securely use your Chrome-based computer.

Every Chrome notebook will ship with built-in cellular data connectivity (from Verizon in the US), meaning that, providing you're in mobile range, you can always be connected.

There'll be daily, and pay-as-you-go data plans from the US provider on top of the 100 minutes of free data each Chrome notebook owner will receive for the first two years.

Cloud-based

Google's Chrome OS is a cloud-based operating system that will compete against the likes of Apple's OS X and Microsoft's dominant Windows 7, with Google calling it "a real third option."

Google's concept of an operating system is based around the browser, and the Linux-based Chrome OS looks much more like a browser than a traditional OS.

Using its popular Chrome browser as its base, Google is uniting its suite of online products – like Gmail, Google Docs and Google Calendar and others from the Chrome Web Store – to offer software and services that are based online rather than locally.

The other key focus is on speed with Google's first wave of devices offering solid state drives for speedy boot-up, with the search giant keen to get you online quicker.

Most secure OS ever

Chrome OS has a much greater focus on applications, downloadable from the Chrome web store, allowing you to replicate much of a traditional computer's functionality, but keeping most of the software and data online rather than on the device itself.

Google is claiming it to be the "most secure consumer operating system to ever be released". Software and apps will also be updated automatically by the operating system, making it "forever new" and giving users greater security and ease of use.

Verified boot, which will ship with all Chrome notebooks, will also mean that the hardware cannot be changed by software. All of this should seriously reduce the risk of viruses infecting your PC.

Pilot program

Seeing as we'll have to wait until well into next year to get our hands on devices, Google is giving a few folks the chance to test a "limited number" of unbranded notebooks as the refining process continues.

Attendees from the media at the San Francsico event, business partners, developers will be given a notebook in January, while a few members of the public will have the chance to test the OS by contacting Google directly.