Platforms are made up of operating systems. A mobile operating system is the software that controls all basic operations. It allows the installation and execution of applications. Operating systems often have toolkits that allow applications to communicate with each other. Android OS is the largest operating system. Android OS uses an open source operating system under Google. Although the main operating system is open source, other parts are licensed. An Android trademark can only be used if it is certified by Google against the Compatibility Definition Document (CDD) (Healey, 2014, chapter 6, p. 33). Android OS updates are named after desserts (Cupcake, Ice-cream Sandwich, Jelly Bean, etc.). Android provides development tools for creating applications that take advantage of the hardware capabilities available on each device ("Android", nd). The operating system developed and distributed by Apple is iOS. iOS is derived from Apple's Mac OS X and is only available on Apple devices (Healey, 2014, chapter 6, p. 33). It was initially developed for iPhone devices but is now available on other Apple devices. Windows Phone is a proprietary operating system developed by Microsoft as a replacement for its Windows Mobile platform (Healey, 2014, chapter 6, p. 35). Live tiles appear on their home screen as active links to their apps. In 2011, Nokia partnered with Microsoft, announcing that it would make Windows Phone the operating system for its smartphones (Nokia, 2014). Nokia would replace its Symbian operating system with Windows Phone. BlackBerry OS was developed by Research in Motion. It is a proprietary operating system used on Blackberry handheld devices ("Mobile Operating Systems,...... middle of paper......e-WP_MobileApps2.pdf. Operating Systems mobile operating systems (mobile operating systems) explained (2011, August 10). Accessed March 3, 2014 at: http://www.webopedia.com/DidYouKnow/Hardware_software/mobile-operating-systems-mobile-os-explained.html. Nokia Story. Retrieved March 3, 2014 from: http://www.nokia.com/global/about-nokia/about-us/the-nokia-story/ Orlando, D. (January 25, 2011). Retrieved March 7, 2014 from: http://www.ibm.com/developerworks/cloud/library/cl-cloudservices/iaas/ December 17, 2010. Cloud Computing Fundamentals: A Different Way to Deliver Computing Resources. DeveloperWorks. Retrieved March 7, 2014 from: http://www.ibm.com/developerworks/cloud/library/cl-cloudintro/index. HTML.