Microsoft admits shared kernel across NT versions.

Microsoft has owned up to the fact that Windows NT Server and Workstation share a single code kernel, despite insisting that different prices and licence conditions should apply to the two products on the grounds that they are very different from each other.

The software giant's insistence that NT Workstation is a different product from NT Server has already brought it into conflict with its customers.

This summer, angry beta testers forced Microsoft to remove a software block from the final version of NT Workstation 4.0. The block was intended to enforce licence conditions preventing the use of NT Workstation as a Web server by limiting the number of Internet accesses which it could handle.

Microsoft was accused of trying to force users to buy NT Server, which costs around # 500 more than Workstation.

The supplier admitted last week that just two registry values in NT determine whether the operating system configures itself as a server or a workstation platform. 'When the system boots up, it makes automatic changes to configure itself as either Workstation, or Server,' said Microsoft's UK marketing manager Mark Hassall.

Microsoft UK would only confirm the existence of the single NT kernel - initially publicised by a US software developer - after clearance from the company's US headquarters last week.

The single kernel was found by Mark Russinovich, consulting associate for Open Systems Resources, who said: 'There are two system threads in NT which have been written expressly to prevent the two values being changed, and to change them back if they are altered.'

He has written a utility to change the settings, which, he says, are the only things which prevents NT workstation running Microsoft's Internet Information Server Web server software, or the BackOffice suite of utilities.