Mozilla plans to release the Firefox OS in 2013 but with a new Firefox add-on, you can get a taste of new OS straight from your desktop browser.
Mozilla has made available the Firefox OS Simulator
a prototype Firefox add-on that makes it easy to install B2G on your Windows, Mac or Linux computer. B2G is undergoing heavy development, and the Firefox OS Simulator makes it easy to stay up-to-date. Mozilla's main goal with 1.0 is to make it easy for app developers to run B2G and install apps that they are working on into it.
The Firefox OS Simulator is different from some mobile environment simulations in that it doesn?t create a virtual computer. Instead, it is actually B2G Desktop, a version of the Boot2Gecko project that is built for desktop operating systems. This allows the Simulator to run very quickly and with minimal startup time on your computer.
Firefox OS will join a crowded field of mobile operating systems - and iOS, Android,Windows Phone 8 and the upcoming BlackBerry 10. Mozilla will have to convince developers getting interested in the new OS.