Hi, this is Bill. Gimme a bite of your Apple

Imagine if the Reverend Ian Paisley were to appear on a video screen at Sinn Fein's next conference, to announce that he had taken a seat on its controlling council. Or the reverse - Gerry Adams being inducted as a priest into the Protestant Church and hailed by Paisley as the great saviour of the Unionist cause.

Amazing? Unlikely? Of course. But that gives you some idea of the frisson that ran through the crowd of programmers - who take computers every bit as seriously as some people take religion - at Apple's MacWorld conference in Boston when the luminous, grinning, giant face of Bill Gates, head of Microsoft, appeared, and told them that his company had bought $150m worth of non-voting stock in the company.

The crowd hissed and booed. One would have expected at least that somebody would have stood up with a heavy object and hurled it at the video screen, to shatter the ghastly vision of Microsoft's triumph over a company which has always had the better ideas, but has consistently failed in that vital field - marketing.

That image, of smashing the monolith, was the one that Apple chose in 1984 to push its "windows-based" PCs over the perceived tyranny of IBM, which since 1982 had dominated the market for corporate PCs. But Apple chose the wrong target. It should have been attacking the software, not the hardware. For in the 1980s, the corporations did stop buying IBM - but they bought cheaper machines which could still do all the same things as the IBM ones, because they ran the same software, written by Microsoft.

Yet the surprising thing about this week's announcement (if the two warring, neo-religious sides can be brought together without Mo Mowlam having to be parachuted in to act as peace-keeper) is that in the long run, the real beneficiaries might be you and I, rather than just Bill Gates.

We might in future get computers which have the same look and do all the things we really want, at a price that we want. For Microsoft might even find it useful to incorporate some of the most useful aspects of Apple's operating system - such as the seamless nature of its operation, the look and feel of the "desktop" on the screen, the way it handles files, its insistence that every program follows certain "Human Interface Guidelines", established by ergonomists rather than programmers.

Why don't we have that already? Because Apple had the good ideas, but Microsoft had the muscle. The two have always been arch-rivals, incompatible: you can't put Apple software on to a machine that runs Microsoft's Windows operating system, and you can't run Windows on an Apple machine. They're water and oil, chalk and cheese, Tom and Jerry. Yet now they're strangely linked, because Gates needs Apple to survive.

That's surprising, because in the past, Gates has never been afraid to fight dirty to see off rivals. For example, in 1991, a company called Digital Research developed an operating system called DR-DOS, that would run underneath Microsoft's Windows 3.1. The advantage for computer buyers would be one of choice: DR-DOS or Microsoft's MS-DOS. Let the best product win.

Except Microsoft's programmers responded by inserting a few lines of programming code into Windows 3.1 that detected DR-DOS if it was being used, and flashed up a screen message saying "non-fatal error detected". Non-fatal? What the hell did that mean? Users, frightened by the gobbledegook, bought MS-DOS instead, which didn't come up with inexplicable messages.

Effective? Certainly. Gary Kildall, founder of Digital Research, wrote bitterly in his memoirs, "I have grown up in this industry with Gates. He is divisive. He is manipulative. He is a user. He has taken much from me and the industry."

Similarly, though Apple used to have more than 10 per cent of machine sales, Microsoft was always strangely tardy in writing programs that could run on them. MS-DOS versions were always there first - even though the software and the operating system are written in different parts of the company.

But though Microsoft years ago won the commercial battle, it couldn't win the ideas battle. Apple was years ahead in offering an operating system for a personal computer which relied on "windows" - a "Graphical User Interface", or GUI - rather than one based around typing commands and file names at a blinking prompt (known as the "Command Line Interface", or CLI).

CLIs are what you see in films to denote behemoth machines. The blank screen's blinking cursor immediately suggests that the machine behind it is both complicated, unfriendly to the user (unless you know the magic words, it won't work) and old. MS-DOS was a classic CLI. In fact, Windows 3.1 and Windows95 still are CLIs - but they disguise the fact beautifully by running a sophisticated graphics program - Windows - over the blinking cursor.

Sneaky? That doesn't concern Gates. His real worry, and his most significant fights, have been against the US Department of Justice's anti-trust lawyers, who have investigated Microsoft's near-monopoly of the desktop several times.

Without Apple, Microsoft would be a logical target for a break-up on monopoly grounds. A three-way split, into an operating system company, an application software (such as word processing and spreadsheets) company, and an Internet software company would be logical. It would destroy the empire Gates has worked so intensely to create. Therefore, keeping Apple alive is utterly in his interest.

There is a perception (reinforced by Microsoft's huge marketing operation) that it never makes mistakes. That's entirely untrue. But Gates knows that it's better to make a lot of decisions quickly, correcting as you go, than to move slowly and correctly. Much is often made of his wealth, based on his stock value. People assume he's thus in it for the money, that he wants to own the world.

From meeting and interviewing him, and watching him operate for more than 14 years, I would say that actually he doesn't care about money. What he wants is for the world to agree that he's always right, and get itself in order so that what he thinks turns out to be right.

His vision of the future, as depicted in his book The Road Ahead, is dull and full of platitudes, lacking the sparkle of diversity and danger that real endeavour encourages. But possibly Gates doesn't want the world to be like that. Steve Jobs, one of Apple's founders, who is now back on its board, and one of the architects of this week's deal, told the shocked audience: "We have to let go of the notion that for Apple to win, Microsoft must lose." To really fit Bill Gates's world, we should let go of the idea that Microsoft can lose. The question is, will we win too?