Will Longhorn be worth the pain?

And one compelling reason to upgrade, he believes, is Longhorn's new Active Protection feature, which recognises the presence of viruses or worms by their behavioural characteristics rather than their signatures and is also aware of whether a given machine is patched or not.

But Olivier Nguyen van Tan, chief operation officer of Pierre Audoin Consultants, believes that Microsoft will also push a fifth key tag line in the form of 'integration innovation'.

"When Microsoft started its platform strategy about three years ago, it was the first time that it had pushed the idea of integration innovation, meaning that all of its products are linked together and work together efficiently. Integration is a big pitch for Microsoft because the appeal to the market is that it means more productivity and less cost," he says.

But the big question, of course, is whether the messages around such apparently mundane, albeit useful, functionality will be enough to tempt the average customer to switch, particularly given the time and resources that such upgrades demand.

Jump warns that even a minor OS upgrade generally takes enterprises between nine and 15 months to complete, including testing and roll out, while major releases can take anything from between 12 to 18 months.

Over the next two years, organisations should try "as much as possible" to move their PCs to the latest version of Windows, which in the case of the client version means XP, because it will make migration to Longhorn much easier, explains the Gartner analyst.

Although it is currently unclear how much of a leap from XP to Longhorn it will be, Jump does expect the Avalon user interface element to make the move as tricky as it was from Windows 3.1 to 95, which involved the rewriting of many older applications.

"If you skip versions and aren't on XP, you'll have to do a big bang migration and you need a very big budget for that. Also it costs more in the long-term for a big migration," she warns.

The issue is, however, that only 32.5 percent of the total desktop installed base is currently using XP, while another 38 percent is on Windows 2000. A further 2 percent employ MacOS, 1.5 percent have Linux clients and the remaining 26 percent still use unsupported versions of Windows, including 95, NT 4 and Millennium Edition.

In short, if nearly two thirds of Microsoft's customers need to move to XP before they even consider migrating to Longhorn, it appears that the supplier has quite a major challenge ahead.

On the upside though, Quirk indicates that the OS will run on the same hardware as XP works on now, which will at least save money here, although he "won't promise that it will run on a low spec machine".

But the downside for Microsoft is that none of the analysts are advising organisations to rush into anything, recommending rather that they take a pragmatic approach and adopt the OS only where they see real business value.

"The key is to focus on the value of the upgrade. Applications that provide compelling features may make it worth moving, but you also have to think about how much it costs to do mass deployments," Macehiter concludes. "There are no hard and fast rules, so I think it will be a trickle migration and consumers will probably take it up faster than companies because they'll buy new PCs with Longhorn loaded."

On the final page, you can find an explanation of the the original 'three pillars of Longhorn', and what happenned to them in between their announcement and the current time.