A tablet computer, or simply tablet, is a one-piece mobile computer. Devices typically have a touchscreen, with finger or stylus gestures replacing the conventional computer mouse. It is often supplemented by physical buttons or input from sensors such as accelerometers. An on-screen, hideable virtual keyboard is usually used for typing. Tablets differentiate themselves by being larger than smart phones or personal digital assistants. They are usually 7 inches (18 cm) or larger, measured diagonally.
Though generally self-contained, a tablet computer may be connected to a physical keyboard or other input device. A number of Hybrids that have detachable keyboards have been sold since the mid-1990s. Convertible touchscreen notebook computershave an integrated keyboard that can be hidden by a swivel or slide joint. Booklet tablets have dual-touchscreens and can be used as a notebook by displaying a virtual keyboard on one of the displays.
Conceptualized in the mid 20th century and prototyped and developed in the last two decades of that century, the devices only became affordable and popular in 2010.
As of March 2012, 31% of U.S. Internet users were reported to have a tablet, which was used mainly for viewing published content such as video and news.Among tablets available in 2012, the top-selling line of devices was Apple's iPad with 100 million sold by mid October 2012 since it had been released on April 3, 2010,followed by Amazon's Kindle Fire with 7 million, and Barnes & Noble's Nook with 5 million.