IBM on Tuesday offered to make it easier for competitors to provide maintenance services for its mainframe computers, a move that helped European regulators to close an antitrust probe.

The European Commission, the European Union's competition watchdog, opened two investigations into whether IBM was abusing its dominant position in the market for mainframe computers in July 2010. One of the probes focused on the company's maintenance services.

In August this year, the Commission informed IBM of its concerns that the company may have abused a dominant position by imposing 'unreasonable' supply conditions for certain inputs to competing suppliers of mainframe maintenance services. To address the concerns, IBM committed to ensure the expeditious availability of certain spare parts and technical information to Third Party Maintainers (TPMs) in the EEA, on reasonable and non-discriminatory terms and conditions over a period of five years.

Mainframes are powerful computers which are used by large companies and governments to store and process critical information.

"I commend IBM's readiness to address our concerns about fair competition in the market for large computers which are crucial for the functioning of today's economy," said Commission Vice President and Competition Commissioner Joaqu?n Almunia.

A summary of the draft IBM's commitments is published in the EU's Official Journal.

The Commission also closed a separate investigation into IBM after three small rivals withdrew their complaints that the firm had tied its mainframe hardware with its operating system.

IBM had said at the time of the allegations that Microsoft and other competitors had inspired the actions by emulator software vendor T3 Technologies Inc. and TurboHercules.

The third complainant was Texas-based Neon Enterprise Software.