MS-DOS Not Stolen, New Forensic Analysis Concludes

theodp writes "Challenging earlier assertions that Bill Gates got the rewards due Gary Kildall, a forensic analysis conducted for the latest issue of IEEE Spectrum concludes that the landmark MS-DOS operating system which Bill Gates and Microsoft licensed to IBM was an original piece of work, not stolen goods. Using his company's CodeSuite forensic software, Bob Zeidman said he found no evidence that QDOS or MS-DOS was copied from or was a derivative of Gary Kildall's CP/M. So, what do you think of Microsoft expert witness (pdf) Zeidman's "if-the-codebase-doesn't-fit-you-must-acquit" arguments?"

Comments

Re:Alternatively...

[squiggleslash]

More likely CodeSuite is right.

I know everyone wants to believe the story that a devious Bill Gates simply changed the copyright message on a copy of CP/M and re-released it, but there are numerous issues with the story:

- CP/M is tiny. Really, really, small. And has a well documented API. Anyone conversant in 808x assembler can put together a clone in a matter of days. This isn't an academic statement, I put together one myself for a A Level Computer Science course in the 1980s when I wrote a "CP/M emulator" for the Sinclair QL as my final project. (Appropriately the Sinclair QL's native operating system is also called QDOS. Go figure.)

- QDOS wasn't even a direct clone. The largest - or at least most complex - component of CP/M is the file system - almost everything else is an almost 1:1 call to a BIOS routine. And QDOS didn't have CP/M's file system - it used FAT, not the somewhat inefficient CP/M system which, IIRC, required scanning the entire directory to determine where the free sectors were. So even if someone had started off with a copy of CP/M and directly ported it, 90% of it or more would have had to be rewritten to produce QDOS.

The stories of Gary Kildall typing in some obscure set of keystrokes causing a copy of PC DOS to announce that it was actually CP/M - haha! - always struck me as improbable, and the fact they only appeared in dubious sources several years after this had supposedly happened makes me think the stories are outright fabrications. That doesn't mean there weren't potential copyright issues, and I suspect most of the stories of IBM somehow settling with DR over the similarities have some elements of truth - but this is because this was the early eighties, the era of Pacman lawsuits, to be followed a few years later by Apple's infamous look and feel suits against DR and Microsoft/HP.

In terms of actual code being copied however - no. It would, arguably, have taken more work to translate CP/M into 8086 assembler and then make all of the changes necessary to turn it into QDOS than it would to write QDOS from scratch. QDOS had a similar API, and a similar but not identical shell. Otherwise it wasn't remotely similar.

Re:meh

[bill_mcgonigle]

Now nothing was illegal - but my god. What a complete lack of any decent human characteristic.

I'm no Bill Gates fan, but that's a hard case to make. He had information that both IBM and Brock lacked, and without that information, Brock might never have made any money on the product. There's no denying that his mother's connections to IBM folks made that happen for him, but he was the essential link in the chain (even if not a very talented one). It's those essential connections where profit happens.

Gates gave SCP a decent payday (explicitly an acceptable price to Brock) and then gave Patterson a job three times, and bought Patterson's company from him. Heck, Patterson was such an early Microsoft employee that he could have made (did make?) a killing on its stock. SCP made healthy independent profits riding on the coattails of Microsoft's IBM-PC success, but then sued them for more profits, which only wound up in a settlement. Since we're judging all this in hindsight, Brock would have been better off joining Microsoft with Patterson if he wanted to share in its profits.