Macintosh, Windows, or Google? 

Search engine giant Google finally unveiled the first "Chromebook" notebooks at the Google I/O conference on Wednesday, laptop computers from manufacturing giants Samsung and Acer that use Google's Chrome operating system and will go on sale in June.

The new Web-centric PCs are a clear incursion into territory dominated for decades by computers powered by the Microsoft Windows and Apple Macintosh operating systems.

"These are not typical notebooks," explained With a Chromebook you won’t wait minutes for your computer to boot and browser to start. You’ll be reading your email in seconds. Thanks to automatic updates the software on your Chromebook will get faster over time."

For nearly two years Google has touted Chrome as an alternative to Microsoft Windows, but has faced delays launching PCs designed to use the software. Meanwhile, the exploding market for smartphones and tablets using Google's Android operating system has quickly taken center stage for the Internet heavyweight, and some observers say Google should reconcile the two. 

Chrome OS assumes you’re always in your browser -- which is the access point for most of your files anyway, right? Web pages, e-mails, documents on Google Docs, photos stored at Flickr, video chats, streaming music from Pandora ... most of what you do is online, isn't it? Skip the traditional desktop and save time, simplicity and memory, Google argues. 

"At the core of each Chromebook is the Chrome web browser. The web has millions of applications and billions of users. Trying a new application or sharing it with friends is as easy as clicking a link," explained Upson and Pichai.

And because it doesn’t load a bunch of background stuff, Chrome OS boots almost instantly. Early demos Google showed last October reveal Chrome OS booting in 7 seconds or less -- significantly faster than the traditional operating systems from Microsoft and Apple.

Google underscored the point in a promotional video, in which the Internet giant estimates that the average desktop user spends 90 percent of his time in a browser -- more than enough to justify the use of a web-only desktop.

Chromebooks will sell at and Best Buy this summer starting at $349, the company said.