TUHS November 2024

tuhs@tuhs.org

24 participants
12 discussions

Re: SCO's "evidence" (was: RIP Darl McBride former CEO of SCO)

by jnc＠mercury.lcs.mit.edu

> From: Warner Losh >> On Mon, Nov 4, 2024 at 8:14PM Larry McVoy wrote: >> The bmap implementations I saw were bit for bit identical, same code, >> same variables, same style, same indentation. I'm 100% sure they were >> not independent. > They are different in 4.3BSD. They are different in 4.2BSD (but less > different). The underlying filesystems are different on disk, so they > routines have to be different. That last sentence points out something important that people need to remember in this discussion: in between 4.1 and 4.2 (technically, in 4.1B), BSD switched to the BSD Fast File System, so I very much doubt that the low-level (i.e. logical file block to disk block) file system code in anything after 4.1A looks much like the AT+T low-level file system code. (I have no idea how the BSD code compares to the Linux file system code, but that's between the Linux people, and Berkeley.) Noel

4 months, 3 weeks

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

by 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

4 months, 3 weeks

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TUHS November 2024