Does SCO own read-copy-update?
Now, it's hard to point at a particular spot in the kernel and say "this is the NUMA (or SMP) implementation;" that code tends to be widely distributed. But read-copy-update is a different story. RCU is a complex locking technique that is well suited to data structures that are read often and modified relatively rarely; LWN covered RCU on the Kernel Page almost one year ago. The RCU patches did indeed come from IBM, with early patches showing up in the first part of 2001. IBM also presented RCU at the 2001 Ottawa Linux Symposium. SCO could conceivably have a case here.
The origins of RCU are described in this paper by Paul McKenney and John Slingwine. In the acknowledgements there you'll find:
The paper is intense and detailed - if its authors copied the technique from Unix, they went to unusual lengths to track down earlier work, perform benchmarking, and apply complicated mathematics to the question of which locking scheme is best. The real proof of origin will be in the reports the authors sent back to various funding agencies over a period of almost thirty years. It would appear, however, that SCO is going to have a hard time establishing ownership of this technique.
The code, however, could be a different story. The original Linux RCU patch was taken out of Sequent's old Dynix/ptx operating system. Information on Dynix/ptx is a little hard to come by now, but the Internet Archive has its uses... here's a copy of a Sequent.com page from 2000 describing the system. Among other things, this page says:
So, work from project Monterey did go into Dynix, and code from Dynix went (after some significant transformations) into Linux. So it is truly possible that SCO is sitting on a code base which contains an RCU implementation that is remarkably similar to the one found in the Linux 2.5 kernel. Who owns that code, however, will depend entirely on the history of contracts between SCO and IBM. It seems unlikely that RCU was part of the original Unix code base; more likely it was added to Monterey by Sequent/IBM. Depending on what contracts IBM signed, it may well have given up the right to release the RCU code under the GPL. Or maybe not.
RCU is used in several places in the 2.5 kernel. It has, in general, been
retrofitted into existing areas of code as a performance improvement. If
need be, those patches could certainly be reversed and RCU removed from the
kernel. It would slow down 2.6, and have a small performance impact, but
it would not be that big of a problem. But that is an issue for the
future; SCO first must prove its rights to the code.
Posted Jun 13, 2003 14:40 UTC (Fri)
by StevenCole (guest, #3068)
[Link] (3 responses)
This patent lists the
Evidently, on 08/15/1999, that patent expired due to non-payment of a maintenance fee, but on 05/31/2000 a petition to accept late payment of the fee was filed, and on 06/14/2000 that petition was granted.
For additional information on this patent, go to the
USPTO Patent Full-Text and Image Database. Select Patent Number in Field 1 and enter 5442758 in Term 1.
If SCO's code is using RCU, they may be infringing on that patent.
Posted Jun 13, 2003 15:08 UTC (Fri)
by freeio (guest, #9622)
[Link] (1 responses)
But then again, since IBM is supporting Linux, there is no problem with Linux using the technique (as opposed to the actual code) either. If IBM contibuted code that used the technique (under GPL) then the technique is OK for that use even if the exact implementation were not. Marty
Posted Jun 13, 2003 15:25 UTC (Fri)
by shahms (subscriber, #8877)
[Link]
If SCO wins the lawsuit on copyright infringement, the RCU code has to be removed from Linux, whoo, it can be rewritten (the GPL doesn't prevent patented algorithms from being used, it just states that the GPL implementation of that algorithm must be "freely redistributable"). But SCO is SOL, given that I don't think IBM is going to say "we just lost a lawsuit to you, so we're feeling inclined to just let you use an algorithm we have a patent on without paying for it" more likely they'll say: "you're free to use the GPL implementation, but if you do, you'd better GPL UnixWare or we'll sue *you* for copyright and patent infringement"
Posted Jun 13, 2003 15:43 UTC (Fri)
by emk (subscriber, #1128)
[Link]
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.
Posted Jun 13, 2003 14:57 UTC (Fri)
by keithw (guest, #3127)
[Link]
Posted Jun 13, 2003 15:27 UTC (Fri)
by southey (guest, #9466)
[Link] (1 responses)
Posted Jun 13, 2003 18:52 UTC (Fri)
by torsten (guest, #4137)
[Link]
Second, the terms of the Project Monterey contract needs to be made public, especially if exclusive rights of code were made.
SCO has, from the beginning, stated that IBM violated their mutual contract by breaking off from the Monterrey project to develop Linux. I think the interpretation of the contract from the Monterrey project will be the defining factor of infringement.
The only real problem for IBM is if they already agreed not to share Monterrey code outside of that project, and are still bound by that agreement. We'll see.
Posted Jun 13, 2003 15:48 UTC (Fri)
by eru (subscriber, #2753)
[Link]
I wonder if she was seeing code snippets that might appear (as C-like pseudocode) in Maurice J. Bach's The Design of the Unix Operating System, a widely read text book? I could imagine some algorithms adapted from it appearing in the kernel, but would that be illegal copying of Unix code?
Posted Jun 13, 2003 15:51 UTC (Fri)
by ssharkey (guest, #4451)
[Link] (2 responses)
+ * And this comment also stands out: + * Author: Dipankar Sarma <dipankar@sequent.com> No SCO copyrights occur anywhere that I could find in the patch. *ASSUMING* that IBM did not assign the copyrights to SCO at some The original author was from Sequent, based on code from an All this "proves" is that there is code from IBM in the kernel. -Scott
Posted Jun 13, 2003 16:23 UTC (Fri)
by iabervon (subscriber, #722)
[Link] (1 responses)
Posted Jun 13, 2003 16:50 UTC (Fri)
by emk (subscriber, #1128)
[Link]
It's possible that the Monterey contract gives each participant the right to use the code developed in it, but not the right to transfer the license to this code to outsiders without the permission of the other participants. Possibly. But I get the impression that the consortium members frequently donated their own, in-house code to Monterey. And if some code was written for Dynix/ptx (on behalf of Sequent), it seems likely the Sequent would retain rights to use the code independently. Would IBM or Sequent really sign a contract which said, "SCO can veto how you use code that you wrote?" Maybe they would, but I'd expect IBM's lawyers to be a bit more cautious than that. The RCU code appears to have been written by one of the original RCU researchers for use in Dynix. IBM apparently now owns Dynix, and the RCU patent.
Posted Jun 13, 2003 17:15 UTC (Fri)
by emk (subscriber, #1128)
[Link] (1 responses)
SCO has complained several times about SCO-owned NUMA code winding up in Unix. This claim has always struck me as odd, because SCO doesn't even support NUMA (link, link). On the other hand, Sequent had deep expertise in NUMA. And Sequent was also the source of the Linux RCU implementation. Since Sequent participated in Project Monetery (along with SCO and IBM), and appears to have been bought by IBM, it looks like Sequent may be a major focus of this case. Perhaps SCO is suggesting that since Sequent's Dynix was a version of Unix, any technology developed by Sequent--no matter how far advanced beyond the ancient SVR4 code SCO owns--is therefore inevitably contaiminated with SCO's copyrighted code? Or are they suggesting that no Project Monterey-related technologies--even if they were largely developed by Sequent or IBM--can be included in Linux? Either claim would be pretty aggressive. Any advanced techniques developed internally at Sequent would probably contain only miniscule traces of SVR4 code, if they contained anything at all. (Similar things could be said about IBM's OS/2 version of JFS, also mentioned in the SCO complaint.) Of course, SCO started seriously looking at the GPL very recently--despite the enormous implications of the GPL for this case--so we have to assume that their lawyers aren't necessarily on the ball. And their initial complaint included lots of dumb errors, too. So maybe SCO is a bit confused, here. It's hard to say.
Posted Jun 24, 2003 17:10 UTC (Tue)
by booch (guest, #1416)
[Link]
Give that man a cigar. SCO's amended complaint seems to make it clear that this is what SCO is basing pretty much their whole case on. As Cringely and a few other have pointed out, it's a pretty hard argument to win. The UNIX license does say that added code becomes part of UNIX. But if the code existed before it became a part of UNIX, then the author obviously must have a right to create unencumbered derivative works from the original source.
Let's assume IBM agreed not to release such code that later got added to UNIX. And assume that they lose the case on the grounds that they divulged information that by contract SCO did not allow. (The language in the contract is a little vague, so it's theoretically possible.) That still doesn't effect Linux. Because even though IBM contributed the code in violation of their contract, they did own the copyright. So after they pay for the violation of their contract, there's no more dispute.
Linux users/distributors are not a party to the contract, so they can't be held liable for anything to do with the contract (with the exception of intentionally disrupting a contract). There's no copyright infringement, since the code was contributed by the copyright owner. There's no patent infringement, since IBM owns the patents. SCO doesn't own the trademark to the word UNIX. So the only thing left they could use against Linux users is trade secret law. That's typically only used against the person who leaked the info, not everyone who distributes it. (The DeCSS case being a good counter-example.) And since IBM intentionnally gave away their copyrighted code, I think the copyright would override the trade secret in such a case. Especially if IBM has already paid for releasing such info to the public.
Posted Jun 13, 2003 17:18 UTC (Fri)
by ncm (guest, #165)
[Link]
He went off to work at Sequent a long time ago.
While there, he and Slingwine invented RCU. (Somebody
else at IBM invented it independently, later.)
When IBM bought Sequent, they got Dynix, and Paul, and the
patent.
Paul started working on getting RCU usage incorporated
into Linux a few years back. The mailing list archives reveal
that for way too long, several of the
kernel maintainers were unconscionably rude over what turned
out to be differences of macro naming style. Now the RCU
technique is used in a half dozen places in the kernel,
and its use will probably continue to grow. It's a brilliant
technique, and remarkably underreported.
IBM has published a license allowing RCU to be used freely
in GPLed code, but retains all other rights. The BSDs can't
use it. One thing is certain, though: SCO doesn't own it.
Interestingly, the patent implicitly forbids use of RCU in
proprietary drivers. That is, the driver vendor would need
a separate license from IBM. It's not clear whether proprietary
drivers can even use the regular kernel header macros without
a license.
Incidentally, while at Sequent, Paul also did seminal work
on SMP/NUMA memory allocators, and some of the principles
he identified are about to be folded into GNU libstdc++ memory
management. I think the kernel memory allocator has yet to be
blessed with McKenney goodness.
Posted Jun 13, 2003 17:22 UTC (Fri)
by xorbe (guest, #3165)
[Link] (1 responses)
Posted Jun 15, 2003 13:38 UTC (Sun)
by edt (guest, #842)
[Link]
Posted Jun 17, 2003 16:31 UTC (Tue)
by angdraug (subscriber, #7487)
[Link] (1 responses)
Posted Jun 19, 2003 20:24 UTC (Thu)
by lovelace (guest, #278)
[Link]
Posted Jun 20, 2003 13:35 UTC (Fri)
by LenZ (subscriber, #1051)
[Link]
http://www.pbs.org/cringely/pulpit/pulpit20030619.html
Read-copy-update technology is covered by US Patent 5,442,758 "Apparatus and method for achieving reduced overhead mutual exclusion and maintaining coherency in a multiprocessor system utilizing execution history and thread monitoring".
Does SCO own read-copy-update?
Inventors: Slingwine; John D. (Beaverton, OR); McKenney; Paul E. (Beaverton, OR)
Assignee: Sequent Computer Systems, Inc. (Beaverton, OR)
Sequent is now part of IBM, is it not? One has to assume that the Monterey agreements included cross-licensing of patents between SCO and IBM, and so SCO is probably covered in its use of the technique described in the patent.Does SCO own read-copy-update?
Of course, even if the Monterey agreements included cross-licensing agreements suing for breach of contract certainly puts them in a dubious position wrt those other agreements. Assuming the Linux RCU code in question was copied from SCO, doesn't the existance of this patent mean that, either way, SCO loses? (I'd pretty much assumed that anyway, even if SCO wins the lawsuit it means they exist as a viable entity for what, another two years?)Does SCO own read-copy-update?
IBM owns Sequent (and the patent), employs one of two inventors
Or linux is infringing on it, or both...
Does SCO own read-copy-update?
This seems to show that IBM has been very careful by going back to original code that predates this project or was unused (JFS came via OS2). Second, the terms of the Project Monterey contract needs to be made public, especially if exclusive rights of code were made. Otherwise there is nothing stopping Sequent and/or IBM from providing the code to two different places under two different licenses. This would mean that SCO doesn't have a case with this code and only can show that IBM may have used knowledge gained to improve this code. But, as pointed out by the NZheretic article, IBM can also claim the same.Does SCO own read-copy-update?
Does SCO own read-copy-update?
A quote from The Age interview: The Yankee Group as well as the other analyst firms and members of the press, were only shown small portions of a few pieces of code. In my case, I saw Unix System V, version 4.1. Incidentally, this particular code is from the early 1980s, and hence predates Linus Torvalds' first Linux code.
Bach?
If you look at the patch, there are several places where the followingDoes SCO own read-copy-update?
copyright occurs:
+ * Copyright (c) International Business Machines Corp., 2001
+ *
+ * (Based on a Dynix/ptx implementation by
+ * Paul Mckenney <paul.mckenney@us.ibm.com>)
+ *
point in it's relationship, HOW, exactly, does SCO claim any
ownership rights?
IBM employee (who also happens to be the author of the paper
cited in LWN, and apparently contributed to IBM's patenting the
technique). Unless SCO somehow obtained all the *exclusive*
copyrights (and rights to the associated patents) to all code
from Project Monterey, it's difficult to see where they have a
claim. In fact, IBM may certainly have patent infringment claims
vs SCO, and/or copyright violations if this code is indeed in
SCO Unix.
It does NOT prove that SCO ever had any rights to that code.
It's possible that the Monterey contract gives each participant the right to use the code developed in it, but not the right to transfer the license to this code to outsiders without the permission of the other participants. This would make sense for a partnership agreement between proprietary software vendors, as it would prohibit commoditization of the results if one of the participants lost interest while letting each of the participants get their money's worth.Does SCO own read-copy-update?
Does SCO own read-copy-update?
What about NUMA? That's Sequent-related, too.
Bingo
Perhaps SCO is suggesting that since Sequent's Dynix was a version of Unix, any technology developed by Sequent--no matter how far advanced beyond the ancient SVR4 code SCO owns--is therefore inevitably contaiminated with SCO's copyrighted code?
I went to school with Paul McKenney.
RCU, IBM, Sequent, and Paul McKenney
It doesn't matter whether is is right or wrong
The company behavior has been completely unacceptable
concerning this matter, and they should be fined for,
uh, causing terror and financial disruption in the
marketplace for advancing their own agenda.
IBM's DMS product from the 70s-80s used something that could be called read Prior art - maybe?
copy update. To avoid locking records being updated it would get the record,
save a copy let the user do his or her thing with it, get the record a second time,
this time locking it, compare the originals. If they were the same the update
would proceed, but the time the record was locked would be quite short.
They called this Save Compare mode. Could this be prior art?
Ed Tomlinson
ps. if my memory serves me correctly the product number was 5746-xc4
Wasn't NUMA code in Linux introduced by SGI, not IBM?
Does SCO own NUMA?
Yes, the NUMA code was first done by SGI. The question there is what licenses does SGI have with respect to the System V code? IRIX is a descendent of System V but what were the terms of their contract?
SGI and NUMA
Seems like Cringely has been reading this article too:
Does SCO own read-copy-update?