Comment Articles

The chip turns 30

Rupert Goodwins AnchorDesk

Published: 15 Nov 2001 16:48 GMT

The 4004 microprocessor was the starting gun for a race unparalleled in human history. Looking back over 30 years of intensive commercial and engineering effort is like tracing the growth of fire from flint sparks to nuclear power, compressed into a single generation. The very fact that you can read this article anywhere in the world just moments after it was written is just one tiny facet of the changes made in the wake of Intel's invention.

Although the prehistory of personal computing seems a long way from the latest chips, some things have remained the same. A programmer who can write Pentium 4 assembly language software can take a 4004 data sheet and use many of the same basic skills to produce working code. Look at the block diagram for the 4004's internal workings and you'll find the arithmetic logic unit, which does sums and looks at the results. You'll see a set of registers to hold work in progress and an instruction decoder that turns programs into the signals that drive the processor's circuits. The same ideas are in the Pentium 4, although the circuits themselves are immensely more capable and work in far more sophisticated ways. In a way, that's not too surprising -- this basic architecture was outlined by the genius father of computing, John Von Neumann, in the 1940s. When something works, you stick by it: that's the reason us humans share our underlying body design with vertebrates from 400 million years ago.

The Pentium 4, like the 4004, uses transistors as its basic components. These are switches that are changed from off to on and back again by electrical signals; there are only a handful of ways you can combine these so that they count, compare and make decisions and these same ideas are used as the building blocks for all processors. But while the 4004 used 2250 transistors, the Pentium 4 has 42 million -- that's like comparing the population of a small village to that of the United Kingdom. Yet unlike the population of the UK, every one of those transistors in the P4 does exactly what it's told, often billions of times a second. (The story of how the industry's engineers created the tools and skills necessary to organise, design and test projects on this scale is as incredible as that of the electronics itself, albeit one for another time.)