Gone are the days when operating systems meant Windows or Linux or Mac. In the present days operating systems also mean Symbian, Android, Windows Phone, iOS or Blackberry OS.A mobile operating system is the operating system which controls the mobile device like how Windows or Linux controls a desktop or laptop. Smart phones, PDAs, tablets are few devices which run on Mobile operating system. People use smartphones for many purposes. The basic needs of mobile phones have changed over the years. Mobile phones are not only used for calling or texting which were the basic needs of mobile phone. They love to use the phone on the go to browse, connect with people on web, pay tickets for movies, Shopping, take pictures, watch live soccer and many more. So the mobile companies have responded the people in best possible ways. All said mobile phones have become an essential electronic device that helps us to navigate our day. 
2. What is an Operating system?
In simple words an operating systems is a platform for mobiles to function. Michael Jipping(April 2007, p.2-3 ) tells that Operating system consists of programs that control the device. It is basically a software that manages the resources and provides common service to applications. It is just loaded into the device and instructions are executed like any other software. Operating system plays an intermediate role between hardware and applications in allocating memory and hardware functions like input and output. Altogether it binds the software and hardware together. It presents the software to the hardware. A main feature of mobile operating system is memory allocation. Which application should be given top priority and which should not? 
2.1 Different Mobile operating systems:
4. Windows phone
7. MeeGo OS
1.1 Basic Features of Operating systems:
Comparison of few basic features with respect to latest version of different operating systems. 
FEATURE/OS| IOS| ANDROID| WINDOWS PHONE| BLACKBERRY OS | SYMBIAN| Programmed in | C,C++| C,C++,Java| .NET| Java | C++|
‘Undo’ option| Yes| No| No| No| No|
Official App store| App Store| Android Market| Windows phone Market place,Zune| App world| Symbian Horizon, Ovi Store| Screen lock| Yes| Yes| No| Through 3rd Party S/w| Yes| Sound recorder| Yes, But voice not controlled| Yes but voice not controlled and doesn’t work in background| Can be done through a 3rd party software| Yes but voice not controlled and doesn’t work in background| Yes| Tethering| Bluetooth, USBiphone4,iphone4Sor through jailbreak| Mobile Wi-FiBluetoothUSB| Internet sharingWIFI| Mobile Wi-FiBluetoothUSB| Mobile Wi-FiBluetoothUSB| Multitasking| Only for Apple approved applications| Yes| Yes| Yes| Yes| Bluetooth Keyboard| Yes| Available on most of the versions, else can be done through 3rd party S/w | No| Yes| No| Screenshot| Yes| Yes| No, but possible through homebrew or SDK| 3rd party software| Yes| Official SDK Platform| Mac OS SDK| Linux, Mac OS, Windows| Windows| WindowsMac OS| Windows Symbian or Nokia SDK,Mac OS , Linux| Printer Support| Yes through Airprint| Yes via cloud print| Yes by a 3rd party s/w| No| No|
Symbian is an open source mobile operating system designed for smartphones and it is currently being maintained by Accenture. It was first established on June 24 1988 in partnership with Psion, Ericsson, Moto and Nokia. Later in 2009 Nokia completely acquired the Symbian ltd. In February 2010, the source code of Symbian was published. The Symbian foundation reported that it was the largest codebase in open source history.  The latest version of Symbian is Symbian^3.One unique feature in this version of operating system is the HDMI outlet which lets the user to plug and play...