Showing posts from July 21, 2013

Development of Computers

Development of Computers The earliest known device to record computations was the abacus. It dates back to ancient times and was invented by the Chinese. Ten beads were strung onto wires attached to a frame. Addition and subtraction were read from the final positions of the beads. It was considered the first manual tool used in calculating answers to problems that provided information and in a primitive way storing the results. Abacus Mechanical Clock During the Middle Ages the first closed system in terms of calculating information was invented by use of a mechanical clock. The parts of the clock calculated the time of day. The time was displayed through the position of two hands on its face. The inventor pre-programmed the clock instructions through the manner in which the pull of the weights and the swing of the pendulum with the movement of the gears established the position of the hands on the clock face. Mathematics John Napier (Scotsman mid 1600s) discovered logarith

Scanning Devices

Download free latest unlimited KCSE revision papers @ - Author: Atika M. Nyamoti 3. Scanning Devices -These are devices that capture data directly into the computer. -They can also be defined as devices that use a magnetic or photo-electric source to scan and convert images into electric signals that can be processed by an electronic apparatus, such as a computer.

Pointing devices

Download free latest unlimited KCSE revision papers @ - Author: Atika M. Nyamoti 2. Pointing Devices these are devices used to control the pointer/cursor on the screen. Examples: mouse, joystick, trackball, light pen etc    The Mouse there are different types of mice namely: ps/2, optical, wireless/cordless etc