Touchscreens are cognitively very easy to access as they provide a direct method of control. Unlike a mouse, rollerball, joystick or switch the touchscreen reacts according to where you touch it; there is no need to understand the remote relationship between the pointing device and the computer screen. This makes touchscreens a good solution for very young children and some people with profound and multiple learning difficulties.
As far as the computer is aware a touchscreen is just like an ordinary mouse and therefore can be used to access any software that you would usually be able to operate with a mouse.
There are two major types of touchscreen.
The original touchscreens were fitted onto existing monitors and were very popular with the old BBC computer and early IBMs. However as screens have improved over the years a greater level of accuracy was required that these retrofitted devices could not provide.
New touchscreens are integrated into the screen during manufacture. These are a bit more expensive but they are far more accurate and reliable.
The newer integrated touchscreens are currently available on both CRT and LCD screens.
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