A tablet PC is a light weight slate shaped hand-held computer or a slim note book PC. The idea is to replace the traditional pen and notebook with a tablet PC and stylus or digital pen. Historically the tablet was used by the Egyptians to write on clay tablets with a writing stick. In the present day the clay tablet has been replaced with a screen and the writing stick with a stylus. The tablet PC may be considered the pen and notebook of the future. They typically weigh around 2-3 pounds and their main feature is portability. The idea of a tablet PC was floated by Alan Kay of Xerox but was a commercial failure until now, when the prices have fallen down and it is expected that the prices will fall in future. The first widely sold Tablet PC was Newton of Apple Computers.
The hardware consists of a slim touch screen, stylus, optional wireless keyboard and mouse. In this type of computers the data input is not through the traditional mouse and keyboard but through a stylus or a virtual keyboard on the screen. It also has the facility of data input through wireless keyboard and mouse. The stylus is used to write directly/tap on the screen or fingers are used to input data through the touch screen. There is a magnetic field over the screen which interacts with the stylus electronics, hence the user can rest his hands on the screen without distorting the image and only stylus movement affects the screen. They come in various sizes like 8.5 inch, 10 inch and 14 inch.
There are different types of tablet PCs like slates, convertibles and hybrids. Slates consist of just the screen and the stylus. If a slate is attached with a keyboard it is called a convertible. Typically the keyboard is attached with a single joint and it folds/opens onto the screen. The Hybrid has a detachable keyboard so that it can be used both as a slate or a convertible.
Tablet PCs come with resident softwares like handwriting recognition software, speech recognition software, shorthand entry software, virtual keyboard etc,.
There are various advantages like portability, users who are not comfortable with keyboards find stylus more friendly, they do not interrupt line of sight as they are kept on the table and are helpful in meetings and are handheld so can be used in giving presentation while standing up. The disadvantages of Tablet PCs have been cost till now but since the prices have fallen and are falling, hence is not a constraint anymore.