The iPad is a line of tablet computers designed and marketed by Apple Inc., primarily as a platform for audio-visual media including books, periodicals, movies, music, games, apps and web content. Its size and weight fall between those of contemporary smartphones and laptop computers. The iPad runs on iOS, the same operating system used on Apple's iPod Touch and iPhone, and can run its own applications as well as iPhone applications. Without modification, the iPad will only run programs approved by Apple and distributed via the Apple App Store (with the exception of programs that run inside the iPad's web browser).
Like iPhone and iPod Touch, the iPad is controlled by a multitouch display—a departure from most previous tablet computers, which used a pressure-triggered stylus—as well as a virtual onscreen keyboard in lieu of a physical keyboard.
iPad is sold in Wi-Fi and cellular models. The Wi-Fi connection is used to access local area networks and the Internet. Cellular models have a 3G orLTE wireless network interface which can connect to HSPA or EV-DO data networks in addition to Wi-Fi. Since the release of iOS 5, the device does not need to be managed and synced by iTunes running on a personal computer via USB cable.
Apple released the first iPad in April 2010, selling 300,000 units on the first day and selling 3 million in 80 days. During 2010, Apple sold 14.8 million iPads worldwide, representing 75% of tablet PC sales at the end of 2010. By the release of the iPad 2 in March 2011, more than 15 million iPads had been sold selling more than all other tablet PCs combined since the iPad's release. In 2011, it took approximately 73% of the tablet computing market share in the United States. During the fourth quarter of 2011, Apple sold 15.4 million iPads.