The Mac clone maker being sued by Apple because it installs Mac OS X on generic Intel-based systems said it bought copies of the operating system from Apple itself, court documents show.

In papers filed with a San Francisco federal court last week, Psystar repeated its argument that Apple has abused copyright laws by tying the Mac operating system to Apple hardware.

The filing came in response to an Apple motion asking US District Court Judge William Alsup, who tossed out Psystar's original antitrust allegations against Apple last November, to also throw out the Florida company's revamped countersuit.

"Apple contends that because Psystar is 'distributing computers with Apple's copyrighted software loaded on them' that 'Apple is within its rights in asserting copyright infringement'," said Psystar in the papers filed 7 January.

"Apple's assertion that Psystar cannot distribute computers with Apple software (and that a purchaser could not use the same) would run roughshod over 17 U.S.C.," Psystar added, referring to the section of US law that pertains to copyright.

To make its point, Psystar claimed that it has purchased some copies of Mac OS X - which it pre-installs on the Intel-powered machines it sells under the "Open Computer" and "OpenPro" labels - straight from Apple.

"Psystar distributes computers with legitimately purchased copies of Mac OS loaded thereon," the company said. "Many of those copies [were] directly obtained from Apple.

While Psystar complies with Section 117(b) of the Copyright Act, Apple attempts to usurp those limitations by telling Psystar and its customers that Apple - and Apple alone - will say 'whether, how or by whom its software is ... distributed or used.

NEXT: Apple, argued Psystar, can't have it both ways