A lot has been written about Microsoft's strategy to force IT managers to abandon the long-serving Windows NT operating system in favour of Windows Server 2003. However, though the software giant is keen to move customers to Windows 2003 and the lucrative support contracts that go with it, many firms are in no hurry to shift.

Recent research by NOP found that up to 77 percent of firms of all sizes were still using Windows NT within their IT infrastructure, although only 18 percent were using it as the principal operating system.

Of course, the phenomenon of vendors forcing customers to spend on the latest products by stopping support for older ones is neither a new development or one confined to Microsoft. Most software vendors actually depend on it, otherwise they would only every write one version of any application and would depend more heavily on revenue from support contracts for the products already shipped.

If it were not for the fact that Microsoft is probably making little or no money out of NT, it would probably be content to leave customers to use the platform indefinitely and make their own arrangements for ongoing support. Companies can tap the knowledge of the vast army of IT professionals who have supported NT over a number of years, and there is a library of books and articles on the subject, as well as a maze of online resources.

Most firms hanging on to NT say they are in no hurry to upgrade because the platform is stable and there are many IT professionals who can support NT Server, which has been around for almost a decade, without having to pay Microsoft for the privilege. There is also what vendors call "stickiness", a phenomenon that can be loosely translated as the familiarity with a certain product that makes users sluggish to accept change.

In fact the NOP research suggests that the vast majority of firms are probably running more recent platforms. But it also implies that many have a smattering of older systems that continue to chug away happily running the NT operating system that probably came on the hard disk. Many of these machines probably sit in obscure corners of buildings or remote offices that have been overlooked or ignored by the IT department.

As far as Microsoft is concerned, however, every NT user is a potential customer for a new operating system, and as long as its business is that of selling software, users can expect to be sold upgrades by hook or by crook. And like many salespeople, Microsoft may sometimes dress up its product pitch, to make customers believe that software they don't really need is something worth having.