Personal computers

Abstract

The personal computer industry has a short story history which is dominated be a principle of standardization of a rather ad hoc nature. However, due to the enormous sales of personal computers, these standards are commercially more important than those set up by standards organizations. They are, of course, defined by the largest computer company in the world, IBM (International Business Machines). The real-time nature of such a single tasking dedicated processor system will be illustrated by a real example. The history of the IBM-PC began in 1980 with a design which has often been criticized by the computer professionals. The arrival of new models was followed by an enormous commercial success, which took many people, including some in IBM, by total surprise. The major components of the IBM-PC will be described along with its modular and open nature which was a major factor in encouraging third-party developments. The power and weight of the largest computer manufacturer was reinforced by established large and medium producers as well as the, so-called, back garage small companies which gave an artisanal flavour to the industry. Some idea will be given of the range of hardware and software produced as a way of adding value to the industry's successful commercial standard. Another major industry is the production of IBM compatible personal computers. IBM's competition produced clones which faithful copied the original but could be marketed at a lower price. Another successful approach was the production of a superior model where some compatibility would be sacrificed in order to produced enhanced versions at roughly the same price. Enhancements included faster processors, for example the Intel 8086, and better displays. A short review of some contenders will be given. The most notable exception to the trends desccribed above is the Apple Macintosh which is very successful but does not follow the IBM compatible route. While the hardware is radically different from the IBM-PC, one can find similar classes of software running with a completely different user interface. The design of the Macintosh and the range of available software is described and compared with the IBM-PC. New personal computers are still appearing, some of which look quite different from the IBM-PC. There is often an attempt to unite the best of the Macintosh features with the advantages of the IBM-PC. Notable recent personal computers are the Atari ST520 and the Commodore Amiga. The Atari ST520, and now also the Atari ST1040 with larger memory, offer Macintosh style working for a fraction of the Macintosh price. The Amiga offers new facilities for advanced graphics and stereophonic sound which technically put it well ahead of much of the competition. The Commodore company, however, may have overstretched its finances with such an expensive venture. There is another area of personal computing which is covered by the more expensive and more powerful personal workstation. The personal workstations offer fast processing, multi-tasking and excellent networking. Two of the latest entries are the IBM RT-PC and the Apollo DN3000. Both machines run Unix systems and have an AT bus taken from the IBM PC-AT. As well as using the AT bus for connecting peripherals, it is proposed to offer an AT bus card which is a PC and give this ‘PC on a card’ access to the hardware of the personal workstation. This is an interesting switch since, instead of the bus being inserted into the personal computer, the personal computer is inserted into the bus.