A Microsoft decision to provide licensees with substantially increased access to its source code has helped ease US concerns raised last month.

The company told US and European Union officials it was willing to license its Windows server source code at no additional cost to members of the Microsoft Communications Protocol Program (MCPP) licensing program, giving them access to relevant source code as well as added assistance through online and in-person training in the use of the source code, Microsoft said in a US court filing.

The documents, which include reports from US officials and Microsoft, were filed Wednesday as part of ongoing efforts to ensure Microsoft complies with the final judgments of a US anti-trust case against it, which are contained in a May 2003 court order.

The company's decision to expand its assistance to licensees came in part from concerns filed by US officials in January, according to the documents. In the 23 January filing, US officials said Microsoft needed to significantly expand the resources devoted to responding to issues generated by a US technical committee as quickly as possible.

"Microsoft’s plan - to make Windows server source code available to licensees to assist their development efforts, and to offer licensees both training and technical support - is responsive to Plaintiffs’ concerns," US officials wrote in the court documents.

Microsoft also reported that two additional firms, Hitachi and ONStor, have become licensees under the MCPP programme, bringing the total number of licensees to 25. Hitachi and ONStor will be able to use the licence to create file server appliance products, Microsoft said in the filing. There are 12 licensees shipping products under the MCPP.

In addition to the 25 licensees, Cisco Systems Inc. has taken advantage of the royalty-free protocol license offered through the Microsoft Developer Network, bringing the total number of royalty-free licensees to three, Microsoft said.