IBM owns Sequent (and the patent), employs one of two inventors
Posted Jun 13, 2003 15:43 UTC (Fri) by emk
In reply to: Does SCO own read-copy-update?
Parent article: Does SCO own read-copy-update?
IBM apparently bought Sequent for $810 million dollars. Therefore, if Sequent is the assignee for the RCU patent, IBM owns the patent.
IBM also employed McKenny, one of the two inventors of RCU.
Since RCU was published and patented, SCO can hardly claim RCU is a trade secret. And since IBM appears to control the RCU patent, SCO doesn't have any obvious way to claim patent infringement.
This leaves charges of copyright infringement. For IBM to have infringed on SCO copyrights, SCO would need to have implemented a technique patented by Sequent, and given the code to Sequent. This is possible, but hard to believe. It's certainly more plausible that Sequent wrote the RCU code themselves and later contributed it to Project Monterey, from where it migrated into SCO's code base. But there's no way to tell.
It's also possible that every Project Monterey participant signed a contract with SCO, handing over control of any patents and copyrights for work they developed independently. But again, this is hard to believe.
In any event, the original RCU diffs added only 1,811 lines to the kernel, including copyright notices and documentation. A top-notch C hacker working in user space can average 250 lines/day on tricky algorithms (I've seen it done), so we're looking at a few engineer-months, maximum.
This first concrete allegation of wrongdoing looks pretty marginal. I was expecting something less ambiguous; perhaps a few hundred lines of random subroutines from the SVR4 code, contributed by somebody who didn't understand the responsibilities of a SVR4 license. If SCO wants to claim they own the RCU code, they'd better be prepared to show they actually wrote it, and didn't just misplace the copyright notices when borrowing some of Sequent's code.
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