TODAY - IN PART THREE - HE ROUNDS UP THE SERIES BY LOOKING BACK AT THE MILESTONES OF CHIP DESIGN AND THEN FORWARD TO THE FUTURE OF THE MEDIUM.

In part one and two of this series I have tried to emphasis that computing is very much a team effort, and that while faster processors play an important role they are not the whole story.

I also outlined the fact that the computer chip industry is becoming more and more competitive with leading player Intel now feeling the pressure from companies such as AMD, Cyrix and IBM.

Today, however, we examine the steps that have been taken to reach this point in history and have an educated guess at the close and distant future.

In computer design circles the 1970 "Intel 4004" will always have a special place. Today the "4004" is acknowledged as being the first example of a "general purpose" microprocessor. Before that integrated chips had been designed to serve only one specific purpose.

Designed by Ted Hoff and Frederico Faggin the 4004 chip was used in the very first generation of (very expensive) silicon-based calculators. It contained the equivalent of 2300 single transistors and was the tiny acorn from which chips such as the Pentium Pro range would grow.

Today modern chips can contained over 5.5 million transistors - and given that newer models have caches and co-processors built-in - the number seems certain to grow. However, while these figures give a good rule-of-thumb as to how powerful the processors are, further improvements can still be achieved by further streamlined design.

Progress was quick in those early days and by 1974 Intel had come up with the 8080, the first general purpose chip designed for "full computer" use and already twenty times faster than the 4004 family. This 8-bit chip found its way in to many kit computers - including the famous Altair - and was more notable for bringing the home computer a step closer.

In 1979 Intel produced the 8088 - perhaps the biggest breakthrough chip of all time. This 16-bit processor drove the first IBM PC which was soon cloned by a wide variety of producers. It's introduction sent Intel share prices in to orbit.

The next milestone was the 80286 - the first of the "286" processors - in 1982. The chip contained the equivalent of 130,000 transistors and was powered by a 12 MHZ clock. Natural progress followed with the introduction of the 80386 chip (the first of the 386 models) in 1985 and 80486 (the first of the 486 models) in 1989. The 386 model featured 275,000 transistors, but this number grew to more than a million for the 486 model.

The next breakthrough came in 1993 with the first Pentium range. While containing more than 3 million transistors the chip was better designed to take into account supporting graphics and communications applications. In short Intel had looked more closely at the role of computers in the modern world rather than simply go for number-crunching speed.

The Pentium Pro came out in 1995 and featured what Intel called "dynamic instruction execution" which means that the maths was streamlined before being performed. The chip also featured the first in-built cache. The Pentium Pro now features more than 5.5 million transistors.

While it may be crude to say that other producers have been playing catch-up, this is essentially what has been happening within the chip industry. Intel have even tried to claim, through the courts, that their rivals are merely "copying" there products - although without success.

While many people view the games industry as a bit-of-a-joke many great strides forward have come about by the games industry - who have been at the forefront of producing high standards in graphic images. Commercial areas such as virtual reality and flight simulation have borrowed heavily from the games industry.

While I've outlined most of the key problems of computer speed in parts one and two of this series, the key debate has been about affordable and practical computing.

For those with bottomless pockets many computer problems can be overcome: Computers from Cray are - at their very heart - simply endless rows of processors wired together like a team of horses. In technical circles these are called massively parallel systems or MPPs.

The problem with this type of computer is not only the expensive component parts, but having to invest far more in software that has to be more structured and multi-functional.

Nevertheless, as outlined in parts one and two, the next-step-forward is to provide better support for the main CPU through co-processors. In short, the same sort of idea, but on a much smaller and more automatic scale.

To continue our central idea of computing being separate parts held together by a central theme, we must consider the central demands of computing.

Computer hardware manufactures can only provide components that their customers want. A chip that can perform a record amount of floating-point maths (per second) will be useless unless there is a reasonable commercial market for it. In other words the designers have to design for the commercial market not for the record books.

Equally important is that computers can be improved simply by being more focused and targeted to the purpose that it has to perform. If the computer is a games console, it is obvious that the user wants fast screen updates and multi-channel sound - things that the "serious" computer user might not.

In certain cases there are components - such as hardware caches - that might actually hinder efficiency when running certain pieces of software, because the design of the software doesn't gain any advantages from having them. Or else the cache is too small or too large for the individual application. Therefore I'd be happier describing these functions as "most of a good thing" rather than "all of a good thing."

In more simple terms the design of a computer can never be perfect. There will always be debates as to whether a particular added function helps or hinders in the world it is likely to encounter.

The biggest stone wall facing chip manufacture is the nature of electricity itself. There is a built in limit to how quickly the central electrons can travel so chips cannot simply become faster and faster without end. Some experts say that the future of computing lies in the use of semiconductor lasers and memory based in chemicals - but this will require a breakthrough that will swamp all those that have gone before.