Microsoft last week released a five-year road map for its Windows Server that contains licensing and support requirements experts say are another tactic to pressure corporations to accept the software giant's controversial licensing program.

The road map, highlighted by the first ship date announced for the Longhorn Server operating system, lays out a four-year cycle between major operating system upgrades.

Next year, Microsoft plans a smaller upgrade of Windows Server 2003, which will add support for features such as Trustbridge, directory-enabled middleware that supports the federating of identities across corporate boundaries.

The update will require users without maintenance contracts to purchase a new server license. In addition, the update will be bound retroactively to the five-year support life cycle of the original operating system release, meaning users will lose years off the life expectancy of the software and years of free maintenance support.

However, the update will be available at no charge to customers with Software Assurance maintenance contracts or corporate Enterprise Agreements.

Some say the move highlights the fact that Microsoft is making it tougher for users to reject Software Assurance, a maintenance program that is part of Microsoft's controversial annuity licensing plan. When Software Assurance was introduced in 2001, many users determined the program would increase their software costs and rejected it.

"This will wind users up again because it gives them less and less choice about being on Software Assurance," says Steve Dunton, CTO of activAeon, which develops a tool that analyzes license usage. "Microsoft knows with [Software Assurance] that unless they bring out new software within the three-year life of the contract people won't buy it."

With server software development now on a four-year cycle and with Software Assurance contracts covering only three years, Microsoft needs something to fill the gap to appease those on Software Assurance.

"Software Assurance is a nice side effect of the update. It gives value to people with [Software Assurance]," says Samm DiStasio, group product manager for the Windows Server division.

Some customers have complained recently about not receiving new software, and hence no value, from their first Software Assurance contracts for SQL Server and Windows XP, which are set to expire in June.But as with every other major vendor, Microsoft does not guarantee software upgrades as part of its maintenance contracts.

"If you need [Software Assurance] for these updates, then we are screwed, because we have made a corporate decision not to purchase [Software Assurance]," says George Defenbaugh, manager of global IT infrastructure projects for petroleum company Amerada Hess. He also says purchasing an update and sacrificing two or more years of support doesn't make any sense.

"Buying Microsoft infrastructure software is like buying a perishable item at the grocery store - once the expiration date hits you better not use it," Defenbaugh says.

Some analysts say the support hit and Software Assurance requirements likely will dictate how corporations deploy Microsoft software in the future.

"It is very unlikely that people without [Software Assurance] will buy the interim release every two years; they will leapfrog between major releases," say Al Gillen, an analyst with IDC.

That scenario is what makes Defenbaugh think Microsoft might be polluting a good idea.