Secondary memory

In Chapter 6 we looked at the RAM, Random Access Memory, that is very closely attached to the processor chip. The big problem with this memory is that when the power is switched off, the stored data is lost. In every computer system, it is necessary to be able to store data and programs even when the power to the computer system is turned off. The devices that provide this facility are called secondary memory or backing storage and this chapter looks at a number of these devices. The two main technologies used for secondary storage devices are magnetic surface and optical technology.