Why the world's most powerful computer may be useless

"Better, " Said Abraham Lincoln, "to remain silent and be thought a fool, than to speak out and remove all doubt."

This often comes to mind when famous men make confident predictions which turn out to have been fatuous misjudgments. One thinks of Ken Olsen's 1977 opinion that "there is no reason for every individual to have a computer in his home". (Olsen founded the Digital Equipment Corporation, which was once the world's second-largest computer manufacturer, but is now just a nameplate in HP's extensive collection of defunct companies.)

Then there's Bill Gates's alleged 1981 comment that "640 kilobytes [of RAM] ought to be enough for anybody", or the prediction supposedly made in 1943 by Tom Watson of IBM that the world market for computers was five machines.

The trouble with these quotes is that even when they are accurate, they are usually taken out of context. So while Olsen did indeed voice his scepticism about people needing their own computers, what he meant was not PCs but powerful central computers controlling every aspect of a house's functioning.

As for Gates's quote, nobody has ever produced a convincing source for it and he's always strenuously denied saying it. In one of his newspaper columns in the mid-1990s he wrote: "I've said some stupid things and some wrong things, but not that."

So what about Watson's prediction of the world market for computers? Once again, there's no convincing evidence he ever said it. According to Wikipedia, the earliest known citation is in the email signature of a Usenet member in 1986, which simply says "remark attributed to Thomas J Watson (chairman of the board of International Business Machines), 1943" - not exactly an impeccable source.

Nevertheless, Watson was on many people's minds this week, after a talk given in San Francisco by Rick Rashid, the computer scientist who now heads Microsoft's formidable research division. According to the Financial Times reporter who broke the story, Rashid said that "around 20 per cent of all the servers sold around the world each year are now being bought by a small handful of internet companies - he named Microsoft, Google, Yahoo and Amazon".

If true, that's an amazing statistic, and one that suggests we are well on the way to the kind of world supposedly envisaged by Watson. At any rate, Rashid's figures indicate that the trend towards "cloud computing" is stronger than most commentators have realised. My hunch is that the Microsoft boss may have actually underestimated the trend by including Google in his list. The prevailing belief in the industry is that the search giant does not buy "servers": it simply buys commodity PCs and builds its own server farms out of them.

So the reality might be that Microsoft, Yahoo and Amazon are already responsible for a fifth of all server purchases, while Google continues to build an unknown, but doubtless unconscionable, number of servers in its own sweet way.

If we are moving to a world powered by a small number of megacomputers - made up of four colossal server farms - the question becomes: what will we do with them? At the moment they are used to provide search, file storage, image- and video-serving, email, word-processing and other, relatively straightforward, services. But such petty applications will only scratch the surface of the computing power provided by these giant machines.

Many Microsoft researchers are thinking about this stuff, so it's not surprising that Rashid went on to speculate. The emerging cloud-computing infrastructure would give us, for example, "the ability to assemble truly vast sets of data in one place and crunch them all at once, [and thus] could transform science. If all the data collected by all the Aids organisations around the world were centralised, what more could be learnt that isn't already known?"

The problem - as Rashid observed - is that many scientific researchers feel extremely proprietary about the data they collect. Unlike, say, economists, who are accustomed to working with publicly available shared databases, scientists jealously guard their datasets, and I can't see many being willing to share them for the common good any time soon.

So here's a foolish prediction. We'll build the network of global megacomputers envisaged by Rashid - then wonder what to do with them.