A tablet computer is a mobile computer with touch-screen display, circuitry and battery in a single unit. Tablets come equipped with sensors, including cameras, a microphone, an accelerometer and a touchscreen, with finger or stylusgestures substituting for the use of computer mouse and keyboard. Tablets may include physical buttons (for example: to control basic features such as speaker volume and power) and ports (for network communications and to charge the battery). They usually feature on-screen, pop-up virtual keyboards for typing. Tablets are typically larger than smart phonesor personal digital assistants at 7 inches (18 cm) or larger, measured diagonally. One can classify tablets into several categories according to the presence and physical appearance of keyboards. Slates and booklets do not have a physical keyboard and typically feature text input performed through the use of a virtual keyboard projected on a touchscreen-enabled display. Hybrids and convertibles do have physical keyboards, although these devices typically also make virtual keyboards available.
Conceptualized in the mid-20th century and prototyped and developed in the last two decades of that century, tablet devices became popular in 2010. In March 2012, PC Magazine reported that 31% of U.S. Internet users owned a tablet, used mainly for viewing published content such as video and news. The top-selling line of devices was Apple’s iPad with 100 million sold between its release in April 2010 and mid-October 2012, but iPad market share in 2013 (number of units) was down to 36% with Android tablets selling to 62%. Android tablet sales volume was 121 million devices, plus 52 million, in 2013 and 2012 respectively. Individual brands of Android operating system devices or compatibles follow iPad with Amazon’s Kindle Fire with 7 million, and Barnes & Noble’s Nook with 5 million. By May 2013, over 70% of mobile developers were targeting tablets (versus 93% for smartphones and 18% for feature phones).