The pc revolution Part I

Two technical innovations in the field of microelectronics – the integrated circuit (1959) and the microprocessor (1971) – resulted in creating microcomputers. The IC permitted the miniaturization of computer memory circuits, and the microprocessor reduced the size of a computer's CPU to the size of a single silicon chip.

The first desktop computer designed specially for personal use was called the Altair 8800. (See Figure 1) It was developed by a small firm named Micro Instrumentation Telemetry Systems in 1975. The Altair was a blue, box-shaped machine that measured approximately 43 cm by 46 cm by 18 cm. There was no keyboard, video terminal, paper-tape reader, or printer. The Altair used an 8-bit Intel 8080 microprocessor, had 256 bytes of RAM. Commands, or programs, were input by flipping the switches on the front panel of the machine. A pattern of flashing lights on this panel showed the results of a program.

T hough the Altair was popular among computer hobbyists, its commercial application was limited, since buyers had to assemble the machine from a computer kit¹. The kit contained all of the components necessary to build an Altair computer: a box, a CPU board with 256 bytes of memory, and a front panel. It was sold for $397, barely more than the cost of the Intel 8080 microprocessor that it used. It took an electronics expert many hours to assemble the computer.

Figure 1

An assembled Altair 8800 microcomputer (1975)

T he Altair hardly represented a revolutionary invention, but it encouraged computer experts to take the next step. The personal computer industry actually began in 1977, when Apple Computer, Inc., founded by Steven Jobs and Stephen Wozniak, introduced the Apple II. (See Figure 2) It was one of the first pre-assembled, mass-produced personal computers. Its monitor supported relatively high-quality color graphics. The computer had its own keyboard, power supply, a floppy-disk drive and eight slots for peripheral devices, which gave users wide possibilities for add-on devices and software programs. The machine used 8-bit microprocessors (which process information in groups of 8 binary digits at a time) and had rather limited memory capacity.

Figure 2

The original Apple II Computer

The Apple II initially was used mainly for running video games. Its popularity considerably increased when Daniel Bricklin wrote a program called VisiCalc – the first electronic spreadsheet (computerized accounting program). Other types of application software were soon developed for PCs. Because personal computers were much less expensive than mainframes, they could be bought by individuals, small and medium-sized businesses, as well as by primary and secondary schools. The era of personal computing began in earnest².

Part II

The IBM Corporation, the world's dominant computer maker, entered the new market in 1981, when it introduced the IBM Personal Computer. The IBM PC was only slightly faster than other desktop machines, but it had about 10 times their memory capacity. The IBM PC had one or two floppy disk drives and a color monitor. Intel Corporation's 16-bit 8088 microprocessor was selected as the CPU for the computer, and for software IBM turned to Microsoft Corporation. Until then, the small software company had concentrated mostly on computer languages, but Bill Gates and Paul Allen found it impossible to miss this opportunity. They bought a small operating system from another company and turned it into PC-DOS (or MS-DOS, or just DOS, for disk operating system). The IBM PC became the world's most popular personal computer, and both its microprocessor and its operating system became industry standards.

In 1982, a firm called Compaq Computer Corp. introduced a portable computer that was compatible with the IBM PC. These first portables resembled sewing machines when they were closed and weighed about 13 kg – at that time a true lightweight. Compatibility with the IBM PC meant that any software or peripherals, such as printers, developed for use with the IBM PC could also work on the Compaq portable. The machine was immediately in demand.

Compaq was not only successful but showed other firms how to compete with IBM. Quickly thereafter, many computer firms began offering IBM PC clones³. Rival machines that used Intel microprocessors and MS-DOS became known as “IBM compatibles” if they tried to compete with IBM on the basis of greater computing power or memory and “IBM clones” if they competed simply on the basis of low price.

I n 1983, Apple introduced Lisa, the first personal computer with a graphical user interface. The Lisa's GUI made computers easy and fun to use and eliminated the need to type in complex commands. The Lisa was followed by the famous Macintosh PC, which was developed in 1984 and proved extremely successful. (See Figure 3) It was based on the 68000 microprocessor manufactured by Motorola. The Macintosh was particularly useful for desktop publishing because it could lay out text and graphics on the display screen, as they would appear on the printed page.

Figure 3

Apple Macintosh Computer

The Macintosh's GUI style was widely adapted by other hardware and software manufactures. In 1985, the Microsoft Corporation introduced Microsoft Windows – a graphical user interface that gave MS-DOS–based computers many of the same capabilities of the Macintosh. Windows became the dominant operating environment for personal computers.