chapter  3
11 Pages

The CPU and a microprocessor system

Computer memory devices come in two basic types, RAM and ROM. These words are not as helpful as they could be. RAM stands for 'random access memory', a term which can in fact be applied to both types. ROM is 'read only memory' which means that the computer system can obtain information stored in the memory ('read' it) but can't store anything new in it ('write' to it). RAM stores can both be read from and written to, but both ROM and RAM have the random access facility. Put simply, this means that any data byte stored in the memory chip can be obtained as easily as the next; it doesn't matter whereabouts in the chip it is.