Computer Science Essays - Discuss the current situation with respect to Input Media.

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Input Media.

Discuss the current situationwith respect to Input Media. What are the current limitations and what newdevelopments are in progress:

The typewriter keyboard -Keyboards have been around over 100 years and are in widespread use both ontypewriters and as input deices to computers. The location of letters andnumbers on keys has been a matter of research. Although other typewritersexisted previously, the design given by Sholes in 1868 was the first to includemany of the characteristics of modern day typewriters (Yamada, 1980). Theletters originally had an alphabetic arrangement which gave trouble to fatstypists because the type bars of successive keystrokes would interfere witheach other.

This gave way to QWERTY layout in which the spacing between common pairs of letters was increased to reduce the frequency of jamming. This design also facilitates the frequent alteration of left and right hand which is a key factor in fast typing (Zhai et al, 2003). There have been many attempts to improve the keyboards layouts better than QWERTY arrangements but none of them have been successful and still QWERTY layout is the most commonly used layout in keyboards.

Pointing and Picking Devices: These devices are generallyused for selecting an item, specifying a position, rotating an object, drawinga line or entering text. Some of these devices currently in use arediscussed below.

The touch-sensitive panels - A touch screen deviceproduces an input signal in response to a touch or movement of the finger onthe display. The most important touch screen characteristic is ease of learningand operation. In touch screens, the input device is also the output device andthus it requires no additional space and enables direct eye-hand coordination.Also all valid inputs are displayed on the screen therefore no memorization ofinputs is required. This technology has been very durable in public accessapplications.

The light Pen - The light pen is a stylus thatgenerates position information when pointed towards a display screen. Like thetouch screen, the light pen uses the output display as the input interface andthus it provides a direct relationship between output and input and does notrequire any extra storage space.

The digitizing Tablet - Graphic Tablets consist ofa flat panel placed on a table near a display. The tablet surface representsthe display and any movement (finger or stylus) on the tablet provides cursor locationinformation. A tablet can be positioned separately according to the user'sneeds and they can transmit information in more than two dimensions.

The Joystick - A joystick consist of a lever mountedvertically in a fixed base. It requires only a small amount of space. It iskept remote from the display therefore it does not obscure the screen. It isusually quite inexpensive.

The tracker ball - The tracker ball is amechanical rolling ball set into a surface with buttons associated with it forselection purposes. It is generally comfortable to use for extended periods oftime because users can rest their arms and spin and stop the trackball with thefingers. It requires a small amount of space and can be integrated with akeyboard.

The Mouse - A mouse is a small hand held box thatfits under the palm and fingertips. Movement of the mouse on a flat surfacegenerates cursor movements. Mice have becomes very popular as computerperipheral devices. Cordless mouse are available now which uses infrared beams.

QWERTY Layout -named for the top-left most row of letters.