It will not have escaped your attention that Microsoft is labouring to finish the next version of its Windows operating system, Vista. A version aimed at the corporate market is supposed to be ready for Christmas, with the consumer edition following some time later (missing the Christmas market, which has irritated computer manufacturers and retailers more than somewhat). Last week, Gartner, a leading IT consultancy, predicted that Microsoft would miss those shipping dates.

'Microsoft's track record is clear: it consistently misses target dates for major operating system releases,' the firm wrote. 'We don't expect broad availability of Windows Vista until at least the second quarter of 2007, which is nine to 12 months after Beta 2.' Microsoft challenged this. A company spokesman told CNET News: 'We remain on track to deliver the final product to volume-licence customers in November 2006 and to other businesses and consumers in January 2007.'

So there! The significant thing about Vista, however, is not the shipping date but the fact that it has been an unconscionable time in the making, subject to endless slippages (which have triggered major organisational changes within the company) and - when it eventually ships - will be just a shadow of the system envisaged when it was conceived. And while all this has been going on, Apple has released several major upgrades of its OS X operating system, and the programmers behind Open Source Linux have significant upgrades over the same period.

The difference between Microsoft and Apple can be largely explained by two factors. One is structural: Apple's OS X is based on Unix, which has a different architecture from Windows, and may be inherently easier to upgrade. The other is that Microsoft is a victim of its past monopolistic success: any new version of Windows has to be 'backwards compatible' with the thousands of programs and hardware devices built to work on earlier versions of the operating system. Apple has much less of a 'legacy' problem in this sense.

The really interesting comparison is with Linux, a product of comparable complexity developed by an independent, dispersed community of programmers who communicate mainly over the net. How come they can outperform a stupendously rich company that can afford to employ very smart people and give them all the resources they need?

Here's a possible answer: complexity. Modern operating systems are staggeringly complicated. In terms of the number of their components, and the richness of the interactions between them, they are far more complex than an Airbus or a jumbo jet.

Microsoft's problems with Windows may be an indicator that operating systems are getting beyond the capacity of any single organisation to handle them. Whatever other charges might be levelled against Microsoft, technical incompetence isn't one. If the folks at Redmond can't do it, maybe it just can't be done.

Therein may lie the real significance of Open Source. In a perceptive book published in 2004, the social scientist, Steve Weber argued that it's not Linux per se but the collaborative process by which the software was created that is the real innovation. In those terms, Linux is probably the first truly networked enterprise in history.

Weber likened Open Source production to an earlier process which had a revolutionary impact - Toyota's production system - which in time transformed the way cars are made everywhere. The Toyota 'system', in that sense, was not a car, and it was not uniquely Japanese. Similarly, Open Source is not a piece of software, and it is not unique to a group of hackers. It's a way of building complex things. Microsoft's struggles with Vista suggest it may be the only way to do operating systems in future.

And while we're on the subject of Vista, have you heard Google's whinge to the folks in Washington? It has complained that nasty Bill Gates has made the MSN search engine the default in Vista. 'The market favours open choice for search,' said Marissa Mayer, vice-president at Google's search products division. 'We don't think it's right for Microsoft to just set the default to MSN. We believe users should choose.'

Right on. So will Google provide links to MSN and Yahoo Search on its Home page? You only have to ask to know the answer. Having already ratted on its 'Don't Be Evil' motto by capitulating to the Chinese government, maybe Google should try 'Don't Be Hypocritical' next.