Under the bonnet

Abstract

There is a mystique surrounding computers. I f we say that these machines do no more than process information, how does this help tile nurse wishing to operate the machine? The newcomer's perception is coloured by a natural fear of new technology and a misconception of the abilities of the computer. Although many sophisticated computer systems exist, the principles of their operation can be equally demonstrated by the ordinary home computer. Looking at the basic home computer, such as a Sinclair Spectrum or Commodore 64, what does the potential user see? Tlle computer itself resembles a typewriter keyboard with its QWERTY layout, connected to a domestic television set, a tape-recorder and perhaps a printer. How do these devices combine to make such a powerful machine? First, the keyboard is the means of putting information into the computer, the TV screen displays the results of this input, and the cassette recorder can be used to store a permanent record of the data for later retrieval. At the heart of all computers is a silicon chip, called the central processing unit. This central processor is the main operational device in the computer, being responsible for the majority of functions. It controls both Read Only Memory (ROM), where the operating systems which control the computer exist, and the Random Access Memory (RAM), the area where tile programs and data reside. As well as these important activities, in many microcom-