Symbian

Symbian is a mobile operating system designed for smartphones originally developed by Psion as EPOC32 and later passed to and managed bySymbian Ltd.. As of 2011 it was maintained by Accenture. It was the world's most widely used smartphone operating system until Q4 2010. It has become obsolete since 2011 when Nokia, the last remaining OEM and by far Symbian's most popular OEM, dropped the platform in favor ofWindows Phone.

The first Symbian phone, the touchscreen Ericsson R380 Smartphone, was released in 2000,  and was the first device marketed as a "smartphone". It combined a PDA with a mobile phone. Later in 2000, the Nokia 9210 communicator was released.

The 7650 from 2002 was the first camera phone to hit the European market – it was also Nokia's first with a color screen display and the first to run on Nokia's Series 60 (later known as S60) platform, which would become a major smartphone platform in the coming years. In 2007, Nokia launched the Nokia N95, which integrated various multimedia features: GPS, a 5-megapixel camera with autofocus and LED flash, 3G and Wi-Fi connectivity and TV-out. In the next few years these features would become standard on high-end smartphones.

In 2010, Nokia released the Nokia N8 smartphone with a stylus-free capacitive touchscreen, the first device to use the new Symbian^3 OS. Its 12-megapixel camera able to record HD video in 720p. It also featured a front-facing VGA camera for videoconferencing.

Some estimates indicate that the number of mobile devices shipped with the Symbian OS up to the end of Q2 2010 is 385 million. Symbian was the number one smartphone platform by market share from 1996 until 2011 when it dropped to second place behind Google's Android OS.

In February 2011, Nokia announced that it would replace Symbian with Windows Phone as the operating system on all of its future smartphones. This transition was completed in October 2011, when Nokia announced its first line of Windows Phone 7.5 smartphones, Nokia Lumia 710 and Nokia Lumia 800. Nokia committed to support its Symbian based smartphones until 2016, by releasing further OS improvements like Belle, and new devices, like the Nokia 808 PureView. On January 24, 2013, Nokia officially confirmed that 808 Pureview would be the last Symbian smartphone.

Unlike other smartphone platforms in the early years, Symbian was the first to popularize mobile phone multimedia such as music, video and gaming. The other major smartphone operating systems at the time like Windows Mobile, BlackBerry OS (in those days) and Palm OS were solely focused on business-use. Despite this Symbian S60 still remained as a popular platform for business use as a result of Nokia's Communicator series such as the E90, as well as the Navigator series. Symbian's popularity in multimedia was centred in its Nseries, with devices such as the N73, N93, N95 and N97.

On September 3, 2013, Microsoft Corporation announced that they will buy Nokia's phone business and license its patents for 5.44 billion euros ($7.2 billion).