ABSTRACT
Most people’s idea of a computer has changed from a giant machine in a secure air-conditioned room to something which can be bought in the High Street. The silicon chip is perhaps the most widely recognized and least understood piece of computer hardware. Powerful microcomputers can run applications that would previously have been hosted on a remote mainframe; indeed, many minicomputer systems are faster and more powerful than machines claiming the title of mainframe. There are two advantages of microform: the storage of documents in this compact form poses fewer problems for the library than the bulky hardcopy originals, and rare items may be made available to customers without risk to the originals. The Central Processor Unit contains the logic circuits which allow the meaningful manipulation of data. The most widely used storage medium is the magnetic disk on which data are stored as local changes in the magnetizable material with which the disk is coated.
