Linux vs. SCO: The Decision Matrix

Likelihood

Most likely

Proven

Possible

Very likely

Unlikely

Possible

Possible

Unlikely

Unlikely

Impossible

Evidence

SCO have yet to reveal any conclusive evidence that they can show there is code that they have developed, which is now in Linux illegally.¹

Further, various people (including Linus Torvalds) have pointed out that for those areas of infringing code that SCO have publically identified, SCO didn't develop anyway. IBM (or others) did. Torvalds specifically points this out for the code which implements RCU.⁸

Full, documented evidence of this exists.^{2, 3}

SCO notified IBM of the infringing code problem and for over two months after this event, SCO purposefully continued to ship SCO Open Linux source code, under the GPL. SCO therefore have donated any purported infringing code to the Linux community.

SCO could have released possibly infringing code from their code base, just to subsequently use this as an attack on Linux.

There is no direct evidence on this, but if the firm, which is facing extinction, had planned a final 'Battle of the Bulge' attack against its biggest competitor, Linux, this would be its best-effort chance of doing some damage.

Journalists have reported interviews with SCO staff which have made this direct claim. If so, then SCO UnixWare may be subject to the licence requirements stipulated by the GPL

SCO's Chris Sontag when explicitly asked about this exact issue replied that SCO themselves had no evidence to suggest that IBM had taken SCO code and released it to Linux¹

According to court evidence, there is a lot of un-attributed BSD-licenced code in the former AT&T System V codebase which forms the basis of SCO UnixWare, the centre of this infringing code issue.⁵

It is very likely however, that most/all of extant BSD code in Linux was in place well before any IBM contributions.

Once the exact nature of any purportedly infringing code is known, the Linux revision control process should be able reveal who contributed this code, and a decision can be made on who provided it. At present no direct and unequivocal evidence has been demonstrated by SCO.

One of the world's most respected Unix and Linux kernel source code experts, Greg Lehey has experience with BSD, Linux and proprietary Unix kernels, believes that due to the core architectural differences between AT&T Unix and Linux, that this is highly unlikely⁵

There is some debateable language in the former AT&T-IBM contract for the licencing of System V Unix, that might be interpreted to imply that SCO can claim ownership to extensions written by IBM to the System V codebase. SCO further claim that since IBM gifted this code to Linux, that this constitutes a violation of the SCO-IBM contract.

SCO will need to show how it is able to claim rights to code that SCO did not create, and that IBM has used in various non-System V software platforms.

SCO owns none of the extant Unix patents. Most of the AT&T patents on Unix have also expired some time ago..¹²

What if SCO is right?

If SCO is right and there is infringing code, then the fact that they willfully released any such code within their own Linux kernel distribution, even after they knew that there was supposed code infringement, released that code into the GPL forever, absolving it from any further claims by SCO.

SCO made initial IP claims against IBM in March 6^th 2003², and only removed the source code to its Linux distribution in May 14^th 2003³ Thus SCO have gifted this code to the Linux community.

Further, SCO have also indemnified all users of Linux against any prosecution⁷

Additionally, SCO have indicated that due to their recent realisation of the requirements mandated in the GPL, they cannot legally pursue, on the purported code infringement basis, any organisation (such as Suse or Red Hat) that distributes Linux, as this would be in violation of the GPL.⁹

SCO claims that they were duped into releasing the source code initially, that they didn't realise that the Linux kernel had their source code. There has also been much discussion about legal precedent on this, relating to the selling of pregnant cows.

Even after SCO did come to believe that the Linux kernel contained infringing code, they continued to ship that source code under the GPL. They have thus gifted any purported infringing code to the Linux community.

SCO made initial IP claims against IBM in March 6th 2003², and only removed the source code to its Linux distribution in May 14th 2003³. Thus SCO have gifted this code to the Linux community.

Further, SCO have also indemnified all users of Linux against any prosecution⁷

Additionally, SCO have indicated that due to their recent realisation of the requirements mandated in the GPL, they cannot legally pursue, on the purported code infrigement basis, any organisation (such as Suse or Red Hat) that distributes Linux, as this would be in violation of the GPL.⁹

SCO will certainly claim that they did not release the Linux code as a form of entrapment.

N/A

SCO will need to prove that they owned the IP to any purportedly disputed code. This may be impossible to do (see BSD code issue). Secondly, SCO's legal claim is one of contract violation, so they will need to show that IBM have violated the SCO-IBM contract.

If SCO can prove these points, they may be able to cancel IBM's System V licence used for AIX. However, this doesn't directly affect Linux.

The court may also decide to seek the removal of the disputed source code from Linux, However, the Linux community can seek the reversal of this decision based on the documented fact that SCO themselves purposefully and knowingly elected to donate this same code in the months after their initial notice to IBM.

Further, SCO have also indemnified all users of Linux against any prosecution⁷

Additionally, SCO have indicated that due to their recent realisation of the requirements mandated in the GPL, they cannot legally pursue, on the purported code infringement basis, any organisation (such as Suse or Red Hat) that distributes Linux, as this would be in violation of the GPL.⁹

SCO will claim that all UnixWare code is original and belongs to SCO

SCO will have to prove that this is the case, which may be impossible.

Further, SCO have also indemnified all users of Linux against any prosecution⁷

Additionally, SCO have indicated that due to their recent realisation of the requirements mandated in the GPL, they cannot legally pursue, on the purported code infringement basis, any organisation (such as Suse or Red Hat) that distributes Linux, as this would be in violation of the GPL.⁹

SCO actions to date have been against IBM, but they have hinted that there may be another Unix-oriented hardware vendor that they may target as well.

Regardless, if it is shown that any other party contributed the purportedly infringing code, the fact remains that SCO elected to reveal and release this code under the GPL, even after their epiphany on the infringement.

SCO made initial IP claims against IBM in March 6th 2003², and only removed the source code to its Linux distribution in May 14th 2003³. Thus SCO have gifted this code to the Linux community.

Further, SCO have also indemnified all users of Linux against any prosecution⁷

Additionally, SCO have indicated that due to their recent realisation of the requirements mandated in the GPL, they cannot legally pursue, on the purported code infringement basis, any organisation (such as Suse or Red Hat) that distributes Linux, as this would be in violation of the GPL.⁹

If old Unix code was used in Linux, then this isn't a real issue, as SCO had recently released this code under a quasi-open source licence.⁶

Further, SCO have also indemnified all users of Linux against any prosecution⁷

Additionally, SCO have indicated that due to their recent realisation of the requirements mandated in the GPL, they cannot legally pursue, on the purported code infringement basis, any organisation (such as Suse or Red Hat) that distributes Linux, as this would be in violation of the GPL.⁹

If SCO is right about some of the gifted code belonging to them, this still has no implications to the Linux kernel, and is a contractual matter between IBM and SCO.

Linux kernel developers did not sign or knowingly agree to the derivative works clause in the IBM-AT&T contractual agreement.

Further, if impelled by the US courts, then this offending code will be backed out and Linux continues as before.

However the fact that SCO wilfully continued to release any such disputed code within their own Linux kernel distribution, even after they knew that there was supposed code infringement, released that code into the GPL forever, absolving it from any further claims by SCO.

SCO made initial IP claims against IBM in March 6^th 2003², and only removed the source code to its Linux distribution in May 14^th 2003³ Thus SCO have gifted this code to the Linux community.

If SCO somehow manages to dig up some long-lost patent which has been implemented in Linux, then they have removed thier rights to make claims on that patent through the distribution (over the past 8 years) of the source code which implements any such patent IP, through the release of the code under the GPL¹¹

If SCO claims that it released this source code unknowingly at first, then this defence is removed by virtue of the fact that they continued to distribute their Linux kernel source code after they became aware of any IP issues.

SCO made initial IP claims against IBM in March 6th 2003², and only removed the source code to its Linux distribution in May 14th 2003³. Thus SCO have gifted this code to the Linux community.

Final Outcome

Linux is unaffected

Linux is unaffected

Linux is unaffected

Linux is unaffected

Linux is unaffected

Linux is unaffected

Linux is unaffected

Linux is unaffected

Linux is unaffected

Linux is unaffected

1. No conclusive proof of violated source code:

http://www.newsfactor.com/perl/story/21722.html

2. SCO makes initial claims about infringing source in Linux:

http://www.eweek.com/article2/0,3959,920731,00.asp

3. SCO finally removes their Linux source code from public access:

http://lwn.net/Articles/32124

Some readers have indicated that SCO didn't stop distributing Linux on May 14, and that they downloaded the source code in the 5^th and believe it was still available on June 18. http://radio.weblogs.com/0120124/2003/06/18.html

NB: I have been alerted to the fact that SCO continue to ship their Linux kernel source code, as of the current publication date.

ftp://ftp.caldera.com/pub/scolinux/server/4.0/updates/SRPMS

4. SCO staff claim SCO put Linux code into UnixWare:

http://www.eweek.com/article2/0,3959,1123176,00.asp

5. Greg Lehey's comments on this suit:

http://www.lemis.com/grog/sco.html

6. Caldera/SCO offers several ancient UNIX versions under a quasi-open source

license : http://minnie.tuhs.org/Seminars/AOSS2001/openunix.pdf

Further information on ancient UNIX versions is available here:

http://www.lemis.com/grog/UNIX/

7. SCO, OpenLinux, Linus And The GPL

http://yro.slashdot.org/yro/03/06/24/0237200.shtml?tid=106&tid=185

SCO have granted immunity to SCO Linux customers, but the GPL requires this immunity to be granted to all users of GPL software included in SCO Linux.

http://www.caldera.com/scosource/letter_to_partners.html

8. “The only IP issues they have brought up in a verifiable way has been the RCU [Read Copy Update, a way to access data structures that may be changing on multiple CPUs with less locking than normal] work that IBM did, and that SCO doesn't have any IP rights to that I can see: the patents are all IBM, and the code was written by (and thus copyrighted by) IBM too. Well, it was Sequent at the time, but they're all IBM now”

http://www.eweek.com/print_article/0,3668,a=43740,00.asp

9. ComputerWire: Linux Distributors Appear to be Safe From SCO

"Linux distributors are safe from legal action by The SCO Group Inc, because the company does not want to destroy Linux, according to SCO's SVP and general manager of the SCOsource intellectual property enforcement division, Chris Sontag.

"Although the Lindon, Utah-based Unix operating system vendor is sticking by its claims that Linux contains code that has been illegally copied from its Unix System V, it appears the company is unlikely to follow up its $3bn lawsuit against IBM Corp with similar actions against Red Hat Inc, SuSE Linux AG or others.

http://www.computerwire.info/brnews/6FF3308412856B4D80256D4E005D45FA

10. An excellent overall reference resource on this topic can be found here:

http://sco.iwethey.org/

A simpler resource is this

http://www.wikipedia.org/wiki/SCO_v._IBM_Linux_lawsuit

11. OSI Position Paper on the SCO-vs.-IBM Complaint

http://www.opensource.org/sco-vs-ibm.html

12 The SCO case gets weirder

http://lwn.net/Articles/33902/

Follow the Patents, People

http://www.ssc.com/pipermail/atc/2003-March/000034.html

13. Legal status of this case:

http://radio.weblogs.com/0120124/stories/2003/06/28/legalLinks.html