A French company has filed a complaint with European competition authorities, accusing IBM of allowing customers to run IBM mainframe operating systems only on IBM computers.
Mainframe computers and the associated software and services are still an important source of revenue for IBM.
The complaint by TurboHercules is the latest in a series of similar complaints against IBM under investigation in Europe and the US.
The software company is asking European competition authorities to halt IBM's attempts to tie software to hardware and make its programming interfaces and protocols available to third parties.
TurboHercules claims that when it asked IBM to licence its mainframe operating systems for use with its open source emulation software, IBM accused the firm of patent infringement.
IBM has declined to comment, claiming that it has not yet been notified of the complaint, according to the Financial Times.