Symbian OS

Symbian OS is an operating system designed for mobile devices and smartphones, with reference to related libraries, user interfaces, frameworks and common tools that were originally developed by Symbian Limited. It is descended from Psion's EPOC and runs exclusively on ARM processors only. Nokia acquired Symbian Software Limited in 2008 and established a new independent nonprofit organization named Symbian Foundation.

Symbian OS and related user interfaces, S60, UIQ and MOAP(S) were donated to the organization by its owners for the purpose of making Symbian platform a royalty free, open source software. This platform was named as the successor to the Symbian OS after the official inauguration of the Symbian Foundation in April 2009.

In February 2010, the Symbian platform was officially made available as open source code. It contributed 46.9% on the sale of Symbian-based equipment and smartphones, due to this it became the world's most popular mobile operating system.