iOS (previously iPhone OS) is a mobile operating system developed and distributed by Apple Inc. Originally released in 2007 for the iPhone and iPod Touch, it has been extended to support other Apple devices such as the iPad and Apple TV. Unlike Microsoft's Windows CE (Windows Phone) and Google's Android, Apple does not license iOS for installation on non-Apple hardware. As of June 12, 2012, Apple's App Store contained more than 650,000 iOS applications, which have collectively been downloaded more than 30 billion times. It had a 23% share of the smartphone operating system units sold in the first quarter of 2012, behind only Google's Android. In June 2012, it accounted for 65% of mobile web data consumption (including use on both the iPod Touch and the iPad). At the half of 2012, there were 410 million devices activated.

Android is a Linux-based operating system primarily designed for mobile devices such as smartphones and tablet computers utilizing ARM processors. A secondary target for the light weight OS is embedded systems such as networking equipment, smart TV systems including set top boxes and built in systems and various devices as varied as house hold appliances and wrist watches. Most embedded applications are for ARM based devices but notably Google's Google TV devices use Intel chips with the x86 version of Android. The x86 processor architecture is also utilized, to a lesser extent, in traditional personal computer applications most notably with netbooks and, rarely, laptops and desktops. It is developed by the Open Handset Alliance, led by Google.

Android has a large community of developers writing applications ("apps") that extend the functionality of the devices. Developers write primarily in a customized version of Java. Apps can be downloaded from third-party sites or through online stores such as Google Play (formerly Android Market), the app store run by Google. In June 2012, there were more than 600,000 apps available for Android, and the estimated number of applications downloaded from Google Play was 20 billion.

Windows 7 is the current release of Microsoft Windows, a series of operating systems produced by Microsoft for use on personal computers, including home and business desktops, laptops, netbooks, tablet PCs, and media center PCs. Windows 7 was released to manufacturing on July 22, 2009, and reached general retail availability worldwide on October 22, 2009, less than three years after the release of its predecessor, Windows Vista. Windows 7's server counterpart, Windows Server 2008 R2, was released at the same time.