Apple Computer, Inc. v. Franklin Computer Corp.
714 F.2d 1240 (3d Cir. 1983) - full text opinion
Franklin copied large portions of Apple's operating system software in order to allow its computer run Apple programs*. In a time before hard disk drives, the operating system was stored on ROM chips.
Even though Franklin Computer lost this case, the company survived and is now one of the largest producers of hand-held electronic devices, including the eBookman (discussed on the Random House v. Rosetta Books, LLC page). Apple has long refused to license the production of its hardware to third parties. As a result, it retains a monopoly on producing Apple-compatible computers.
*This link opens a FTP site containing disk images from hundreds of old Apple II-compatible programs.