IT managers have joined Novell in rejecting Microsoft's claims that all Linux distributions may infringe Microsoft's intellectual property.

"I do not believe that my company has an undisclosed balance sheet liability," said Russ Donnan, chief information officer (CIO) at business information provider Kroll Factual Data. Kroll Factual, a subsidiary of global services provider Marsh & McLennan Companies, uses Red Hat Linux servers along with Windows servers in its data centre.

Microsoft chief executive Steve Ballmer openly declared last week that he believes the Linux source code infringes Microsoft's patents (IP), and companies that use Linux, face a latent financial time bomb that he called an "undisclosed balance sheet liability”. Users of SUSE Linux would be free of this, because of Microsoft's deal with SuSE owner Novell, Microsoft claims.

Earlier this week, Microsoft softened Ballmer's remarks but fundamentally stood by them, while Novell's chief executive Ron Hovsepian countered Ballmer's claims in an open letter.

Donnan, who described himself as "not a huge fan of software patents”, said "the threat of such a 'liability' would not in any way influence" whether Kroll would stick with Red Hat or move to SuSE or even Windows. "Steve Ballmer is posturing for mind share to enterprise executives, knowing it will have little to no impact on IT executives," he said.

When Linux began gaining adoption by dotcoms in the late 1990s, many mainstream CIOs considered it risky in part because of their unfamiliarity with the open-source General Public License (GPL) that governs the operating system's intellectual property, according to Gordon Haff, an analyst with Illuminata.

"It wasn't that any circa-1999 CIO had carefully studied the IP issues surrounding Linux, it was that they didn't know much about them and the whole thing sounded kind of fishy to them," he said.

Those risks appeared to become realised in 2003, when The SCO Group, a former Linux distributor-turned licenser, began suing both Linux vendors such as IBM and OS distributor Red Hat for infringing upon its copyrights.

But SCO has made little progress in its lawsuits. Meanwhile, many open-source vendors, including HP, Red Hat, SUSE and others, quickly responded by offering indemnification against potential lawsuits as part of their standard support packages to customers. Others, such as IBM, have long maintained indemnification was unnecessary.

Original reporting by IDG News Service.