We've heard it all before - and we'll check that APIs really are exposed, say regulators

Microsoft's announcement that it is opening up its programming interfaces (APIs) to developers has been greeted with scepticism in many quarters.

The move, announced by chief executive Steve Ballmer at a press teleconference, means developers will get documentation and details of APIs that they were previously charged for.

Microsoft has also been accused in the past of keeping some short cuts to Windows services secret to gives it applications a performance edge over rivals.

Companies are still liable to pay royalties on the use of Microsoft-patented technology.

Interoperability is one of the issues being looked at by the European Union's Competition Commission as part of a new Microsoft anti-trust investigation launched in January.

But the Commission reacted to Ballmer's announcement with some scepticism. It said in a statement: "The Commission would welcome any move toward genuine interoperability.

Nonetheless the Commission notes that today's announcement follows at least four similar statements by Microsoft in the past on the importance of interoperability."

The statement also points out that the Microsoft announcement "does not relate to the question of whether or not Microsoft has been complying with EU antitrust rules in this area in the past. "
The current anti-trust investigation would verify whether Microsoft's change of policy is implemented in practice.

Analysts quoted by Network World said Microsoft's new openness would allow Windows applications to run "nicely" in Linux using WINE, the open-source implementation of the Windows programming interface..

Alternative messaging, calendaring and workflow suites would benefit from being able to work properly with Microsoft's Exchange Server. Vendors wanting to get their client software interoperable with Exchange.