IBM has had a win in its long court battle with SCO over just who owns Unix and, by extension, whether Linux is an unauthorised clone.

Some quick and simplified history: SCO – short for The Santa Cruz Operation – was a software company that offered a version of Unix for x86 chippery. When Linux came along in the late 90s and started turning into a business, SCO more or less sank and it attacked both Novell and IBM for their role in helping to spread Linus Torvalds' brainchild. At stake was whether those who distribute and profit from Linux should share some of their bounty with SCO. If a court had found in SCO's favour, it would have been bad news for Linux.

The Novell suit ran for about six years, but SCO lost. After that, SCO endured all manner of financial strife, but managed to crawl from the crypt more than once. Last year, SCO managed to secure approval to re-open the case against IBM.

Groklaw's now posted a ruling [PDF] from last week in which Judge David Nuffer of the US District Court for the District of Utah appears to deliver good news for IBM.

The crucial bit of the ruling looks to be this paragraph:

SCO is bound by, and may not here re-litigate, the rulings in the Novell Judgment that Novell (not SCO) owns the copyrights to the pre-1996 UNIX source code, and that Novell waived SCO’s contract claims against IBM for alleged breaches of the licensing agreements pursuant to which IBM licensed such source code.

Interestingly, it looks like IBM is hurrying this one along: the ruling says Big Blue moved for partial summary judgement in the case.

The ruling also appears to knock out SCO's claims that IBM has indulged in unfair competition or other commercial no-nos.

SCO is scarcely alive: it's been in bankruptcy for years and appears not to have thrown a punch since 2013. Yet it would be a brave writer who suggested this new ruling is the end of the affair. The SCO zombie has shuffled on after taking much worse punishment than this and come back for more brain-straining action. ®