Showing posts from July 22, 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


Download free latest unlimited KCSE revision papers @ - Author: Atika M. Nyamoti PROCESSING DEVICES THE CENTRAL PROCESSING UNIT(CPU) The CPU also known as the processor is mounted on the system board (mother board) inside the system unit. It’s regarded as the brain of the computer because it does all the processing activities in the computer. The figures below shows the top and bottom view of a the CPU respectively.

The computer Lab and the Keyboard-Review questions

Download free latest unlimited KCSE revision papers @ - Author: Atika M. Nyamoti  The computer Lab and the Keyboard   Review questions How does a computer differ from a calculator? List any three safety precautions one should observe when entering a computer lab