The PC has come a long way since the first IBM was launched, says Alan Stewart
In August 1981, the world's leading manufacturer of mainframe computers took a giant step and announced to an astonished world the arrival of the IBM Personal Computer.

By 1989, it had become clear to Frank Cary, chairman of IBM, that the corporation must have its own machine to head of the "threat" from Apple.

IBM was late into the micro game. The first microprocessor had been produced by Intel in 1971, the first microcomputer, the MITS Altair, which came in kit form, went on the market in 1975, and the first ready-assembled microcomputers in 1977: the Tandy TRS-80 and the Apple II. These machines were extremely popular, especially the Apple.

In 1981, the IBM PC contained 16KB (yes, KB) RAM, optional cassette storage and a monochrome monitor but no hard disk. The processor chip it used, the Intel 8088, was not as fast as its sister chip, the 8086. Altogether, it was not a very promising start, but the new machine had three magic letters: IBM. This meant it was a real computer, not like an Apple or a Tandy.

Why did the PC catch on? First, because other companies could make "IBM- compatible" PCs, as long as they used their own BIOS, the ROM-based software which kick-starts the PC. Second, because IBM let Microsoft, the then- small company that produced the PC-DOS operating system, license it to other hardware suppliers as MS-DOS. The PC really took off, but the real winner in the long run was Microsoft.

The early PC was a stand-alone machine, but by the late Eighties corporate PCs were being networked using Novell NetWare, and LAN applications such as Lotus cc:Mail were starting to appear. Supposedly portable computers (eg, the Osborne 1) were around before the PC, but these were heavy, bulky objects, a far cry from today's notebook PCs, which can be connected to a mobile phone and used on the move.

In the Nineties, the PC has become an Internet client with access to real-time streamed sound and video, and a powerful network work station for games such as Doom and Quake. Although PC sales in America outstripped those of televisions in 1995, the PC is now challenged by the mythical network computer.

Introduced to Britain in January 1983, the PC had by then 64KB RAM, a 160KB diskette drive, a monochrome display and cost pounds 2,080.

Today, for the same money, you would expect a top-of-the-range 166Mhz Pentium with 16MB RAM, 1.6GB hard drive, CD-Rom drive, 2MB video card, 15-inch SVGA monitor, 28.8kbps modem, sound card with speakers, and a whole lot of software.

What will the PC be like in another 15 years - the size of a watch, with a virtual 3-D image, wireless communication and voice control? Why not? The technology's already there. One thing is sure, in 15 years' time the PC won't be anything like it is today.