The three major mobile operating systems currently dominating the smartphone market are Symbian, Microsoft, Apple, and Google Android. 1. Symbian: The predecessor of the Symbian operating system is the EPOC OS developed by Psion in the UK, designed to be a simple and practical mobile OS. Although based on EPOC, its architecture includes features like multitasking, multi-threading, and memory protection. Techniques such as memory-saving and stack clearing effectively reduce resource consumption; these technologies are also applied to phone memory and storage cards. Symbian uses event-driven programming where the CPU shuts down when applications aren't processing events, making it very energy-efficient. However, this complexity makes C++ development for Symbian quite challenging. Many devices running Symbian also support Python, QT, and J2ME for development purposes. Currently, only Nokia manufactures phones using the Symbian OS. 2. Google Android: Android is an open-source operating system based on Linux primarily used for portable devices; there isn't a unified Chinese name yet—many in mainland China refer to it as 'Android' or 'Anzhi.' Initially developed by Andy Rubin with primary support for smartphones before being acquired by Google in 2005 which formed the Open Handset Alliance to enhance its capabilities gradually expanding into tablets and other areas as well. Its main competitors include Apple's iOS and RIM's Blackberry OS; in Q1 2011 Android surpassed Symbian globally for the first time with a market share of over 59% worldwide according to July 2012 data—76.7% within China alone—with several manufacturers adopting this platform today. 3. Apple iOS: Developed by Apple Inc., iOS was first announced at Macworld on January 9th, 2007 initially intended for use with iPhone but later adapted across various products including iPod touch, iPad & Apple TV among others just like Apple's Mac OS X which is Darwin-based thus classifying it under Unix-like commercial operating systems originally named iPhone OS until rebranded as iOS during WWDC on June 7th ,2010 . As of November 2011 , Canalys reported that iOS held approximately thirty percent (30%) global smartphone system market share while achieving forty-three percent (43%) within US markets predominantly found among users utilizing their flagship products such as series of both iphones & ipads.
