Gordon Moore: How I came up with the Law

Intel co-founder and former chief executive Gordon Moore, who became famous for the eponymous law that describes how the number of transistors on a processor will increase, took time out on Wednesday to explain how he came up with his famous law, and what it means for the future:

"This week is the fortieth anniversary of the publication of the article that became the basis for what became known as Moore's Law. It is an article I wrote in response to request to predict what would happen in the next ten years, from 1965 to 1975.

1965 was very early days for integrated circuits. They were mostly used in military applications where there were no cost concerns. The principal themes I wanted to get across [in the article] were that integrated circuits were the route to inexpensive circuits, and this would happen because the systems would get much more complex. At the time I wrote the article, integrated circuits had 30 components in them, and we had one in the lab that had 60 components.

I looked back and saw that we had doubled the number every year. I took this and extrapolated it for ten years to say the number of component would go from 60 to 60,000 on a chip. I frankly didn't expect it to be at all precise. But it fact it turns out to be much precise than it had any good reason for being, and a colleague dubbed it Moore's law.

So in 1975 looked back at why this was happening, and I saw three reasons: First, there was higher density on the chips; second, we were making bigger chips as processing improved; and third, we were squeezing the waste space out of chips.

We had squeezed all the waste space out by 1975 so I said we could lose that factor, and said the number of components on a chip would double every couple of years instead of every year.

Amazingly we have stayed on that trend for 40 years, and we have got to the point where participants realise they have to move along at at least that rate. If you fall behind a generation your cost suffers. It is a self-fulfilling prophecy that the industry recognises it has to go that fast. I have been amazed that we've been able to keep it going so long. I never expected to predict so far in the future.

The nature of exponentials is that if you extrapolate them far enough you always get a disaster. I can see the extra two or three generations of technology likely to proceed, and expect we have another ten or 20 years before we hit a limit. But by then engineers will have budget of billions of transistors to do their designs, so there will be a lot of innovation they're able to continue with."

Q: Moore's Law is often misquoted as referring to computing power doubling every 18 months. Who is to blame for that?
A: A lot of people have applied the term to anything that increases exponentially. I think the thing about power came from an Intel fellow called David House who saw that the complexity of the circuits was doubling every two years but that they were becoming more powerful at the same time, so he figured that computing power was increasing faster. He's the one that deserves credit for that.