[TUHS] IBM's involvement (was: SCO's "evidence" (was: RIP Darl McBride former CEO of SCO))

[TUHS] IBM's involvement (was: SCO's "evidence" (was: RIP Darl McBride former CEO of SCO))

[Douglas McIlroy]

As a bit-part expert witness for the other side of the SCO case, I saw
hundreds of pages of evidence in the form of side-by-side code
comparison. As I recall, the vast majority of highlighted
correspondences were small snippets, often rearranged. I didn't
interact with the lawyers enough to form a solid opinion about where
this stood on the spectrum of coincidence to fair use to plagiarism.
It certainly wasn't wholesale copying. I do not recall being asked to
opine on whether trade secrets had been stolen.

Apropos of rearranged snippets, one of the diff algorithms I
experimented with in the mid-70s identified rearrangements. I
abandoned it because real life code contains lots of similar lines, so
many in PDP-11 assembler programs as to suggest that these programs
are largely permutations of each other. The phenomenon is much less
common in C, but still present; witness the prevalence of code like
      int i, n;
      for(i=0; i<n; i++) {
The phenomenon may have been afoot in the SCO evidence.

In regard to trade secrets, I was surprised when I moved from Unix at
Bell Labs to Linux at Dartmouth and found calendar(1) to be completely
rewritten, but with logic absolutely identical to the original version
I wrote at the Labs. That was so idiosyncratic that the identity of
the two could not have been an accident.

Doug

[TUHS] IBM's involvement (was: SCO's "evidence" (was: RIP Darl McBride former CEO of SCO))

[Greg 'groggy' Lehey]

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On Monday,  4 November 2024 at 17:05:45 -0700, Marc Rochkind wrote:
> By evidence, I mean evidence that was part of the legal case(s). Material
> presented as a part of a marketing, sales, or public relations effort is
> not evidence in this sense.

OK, that makes sense.  Did it contradict the "evidence" that we
mortals saw?  That wouldn't have made sense.

> The way the copyright case ended doesn't mean that Linux development
> didn't violate copyrights. I'm pretty sure that it did, based on
> conversations with a friend of mine who was a technical expert on
> that part of the case.

Yes, I established that in the article that I wrote.  The real
question is how serious the violation was.  In the case (malloc()) it
was put in the Linux tree by somebody at SGI, and its use as
"evidence" appeared to show that System V was still using a very old,
inefficient memory allocation scheme.  More egg on SCO's face than
anything.

> One might ask, how could Torvalds and all those Linux developers
> violate System V copyrights since they had never seen System V code?
> The answer is that corporations such as IBM also contributed to
> Linux, and those corporations did have such access.

I worked for IBM's Linux Technology Centre at the time.  Everything
was very encapsulated.  I had the task of writing a JFS 1
implementation for Linux.  We already had JFS 2, but JFS 1 was a very
different beast.  It was written by IBM, so you'd think that I would
have had access to the sources.  No such luck.  All I got was the
header files.  This was before the SCO debacle, so it wasn't a
consequence of that.  I greatly doubt that any System V code came into
Linux via IBM.

> I just a few minutes ago glanced at the Wikipedia article "SCO–Linux
> disputes" and it's not bad. It does pretty much explain the breach of
> contract case. There is a section titled "IBM code in Linux" that lists
> some technologies (e.g., JFS, RCU), and that's the area that I
> worked on.

The JFS would have been JFS 2, of course--see above.  I can't comment
further.

My understanding had been that RCU originated in Linux (Paul
McKenney).  Following up, though, there's a patent
(https://patents.google.com/patent/US5442758) to this effect that puts
him in second place behind John Slingwine, and it started off at
Sequent.  I discussed the matter with Paul at the time, and he
dismissed the use of System V code out of hand.  Knowing Paul, I
believe him.  What level of code similarity did you find there?

> I wrote a program that could in effect do a "diff" on entire
> operating systems, hundreds of thousands of lines of code. It was
> amazing to see the results.

Did it establish the direction of the transfer?  The other "evidence"
that was published showed SCO claiming that the Berkeley Packet Filter
was part of System V (which I suppose it was), but of course it went
from BSD to System V, and presumably SCO had removed the Berkeley
license header.  And in the RCU case, I could imagine that some of the
RCU code found its way from Sequent to System V.

Greg
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