Firefox OS is an open source operating system built entirely on web technologies like HTML5, CSS and JavaScript. It allows web apps to access functionality previously only available to native apps. The first phones running Firefox OS were released in early 2013 in South America and later in Asia and Europe. Firefox OS is developed by Mozilla and uses three main software layers - Gonk for the Linux kernel and hardware support, Gecko for the application runtime, and Gaia for the user interface which is written entirely in web technologies and controls everything displayed on screen.

2. •What is Firefox OS?
• How it work?
•The first smart phones running Firefox OS is slated to be released in the first
half of 2013. It will first be released in South America, and will later come
to Asian andEuropean markets.
•The phones are being developed by Geeksphone — a Spanish smartphone
start-up — and Telefonica, one of the largest telecommunications companies
in the world (and also Spanish).
•The mozilla firefox os is still on development it is launched on market is on
feb 2013

3. •On July 25, 2011, started this at Mozilla Corporation, announced the
"Boot to Gecko" Project on the mozilla.dev.platform mailing list.
The project proposal was to "pursue the goal of building a complete,
standalone operating system for the open web" in order to "find the gaps
that keep web developers from being able to build apps that are —in every
way— the equals of native apps built forBlackBerry
10, iPhone, Android The announcement identified these work areas:
new Web APIs to expose device and OS capabilities such as telephone and
camera, to safely expose these to web pages, applications to prove these
capabilities, and low-level code to boot an Android-compatible device.
According to "Mozilla says that B2G is motivated by a desire to
demonstrate that the standards-based open Web has the potential to be a
competitive alternative to the existing single-vendor application
development stacks offered by the dominant mobile operating systems.
In July 2012, Boot to Gecko was rebranded as 'Firefox OS' after Mozilla's
well-known desktop browser, Firefox, and screenshots began appearing in
August 2012

4. In this completely open standards and there’s no proprietary software or
technology involved. The software stack is entirely HTML5
HTML-5
Mozilla's HTML 5-based smartphone operating system has been
rebranded as Firefox OS, and the first supported phones will launch in
2013.
Previously named Boot2Gecko, Mozilla's pocket OS is built entirely upon
open web standards. Every app right down to the phone caller will be
made in HTML5, and the OS will allow web-based applications to access
system files: something only native apps can do on Android and iOS and
such.
HTML5 has potential to replicate almost anything you'd see on a typical
smartphone: even 3D games. Apps can also be cached to the phone, so
your mobile doesn't become a useless brick when you lose your data
connection.
Mozilla points to the "removal of unnecessary middleware layers" and the
optimisation towards entry-level devices as something that will let
operators hit a range of price points -- including the lowest end of
smartphones, "helping to drive adoption across developing markets".

5. The initial development work involves three major software layers: Gonk, Gecko,
and the HTML5 layer, which includes the Gaia user-interface.
Gonk
Gonk consists of a Linux kernel and userspace hardware abstraction layer
(HAL). The kernel and several userspace libraries are common open-source
projects: Linux, libusb, BlueZ, etc. Some other parts of the HAL are shared with
the Android project: GPS, camera, among others. Gonk is basically an
extremely simple Linux distribution and is therefore a porting target of Gecko;
there is a port of Gecko to Gonk, just like there is a port of Gecko to OS X, and
a port of Gecko to Android. Since the B2G project has full control over Gonk,
Gecko
Gecko is the application runtime of B2G. Gecko implements the open
standards for HTML, CSS, and JS. Gecko includes a networking stack, graphics
stack, layout engine, virtual machine (for JS), and porting layers
Gaia
Gaia is the user interface of Firefox OS and controls everything drawn to screen.
Gaia includes implementations of a lock screen, home screen, telephone dialer,
text-messaging application, and camera app. Gaia is written entirely in HTML,
CSS, and JavaScript. It interfaces with the operating system through Open Web
APIs, which are implemented by Gecko. Because it only uses standard web
APIs it can work on other OSes and other web-browsers.

6. Mozilla has released some screenshots of its upcoming Firefox operating system
(OS) for smartphones.