The CPU forgets everything every time the power is turned off, which is why start-up takes a few minutes: the CPU must be loaded with instructions before it can work. To back up its operation, it relies on memory stores - fast but unstable, dynamic access memory (RAM), and stable but slower memory from the hard-disk or other storage devices. The computer also has other controllers specializing in looking after, say, the monitor, modem, or a digital camera.
To the average user, this is irrelevant to the job of obtaining results from the computer, but if you bear in mind that the computer is only as good as the instructions given to it, you may remember to approach it systematically and methodically.
Computers are usually built to run continuously for years in an office and so they should be very reliable when used in a domestic environment most problems are to do with the software. You can safeguard your computer's useful life by following some simple rules:
- connect your computer to a surge-protected power supply or block for power plugs.
- do not jolt or attempt to move the computer when it is working.
- earth yourself before opening the computer and touching any internal part or before picking up a component for installation. An earthing wire that attaches to your wrist is readily available.
- once a year, open the computer and carefully vacuum away the accumulated dust - usually worse on the cooling fans and around the drives.
- use virus-checking software and keep them updated, particularly if you are a Windows user.
- keep ample free space at the back of the computer for the air to circulate and keep the machine cool.
