Updated Microware, developer of the OS-9 real-time operating system, this week went ahead with its planned trademark infringement suit against Apple. Des Moines, Iowa-based Microware's beef centres on Apple's decision to call the next major release of the Macintosh operating system, Mac OS 9. That, says Microware, is an illegal use of its OS-9 trademark. The suit is particularly ironic given that Apple is currently suing PC vendors eMachines and Future Power for illegally using its iMac design -- a design that was recently granted trademark status. And, as one Register reader pointed out, "it's also ironic in that when Jobs announced that the new server OS would be called OS X (or Carbon, for the tenth element) he state specifically that one of the reasons that they were skipping OS-9, was that it was trademarked by another company. How he (and the whole legal department) happened to 'forget' this is a mystery". OS-9 a Unix-derived operating system aimed at the embedded market and has been Microware's flagship product since the company was formed back in the mid to late 70s. It was originally released on the Motorola 6800 CPU family and, like the Mac OS, now operates on the PowerPC processor, among others. Microware's suit was filed with the US District Court for the Southern District of Iowa on Wednesday. ® Related Stories Analysis: Apple attacks iMac rip-offs Apple takes anti-eMachines suit to Japan