[a] case where AT&T attempted to see whether its
Unix code had been stolen
Coherent?
I doubt it. The only access to Coherent that I am aware of was Dennis's
site visit (recounted in Wikipedia, no less). Steve's Yacc adventure
probably concerned another company.
Besides the affairs of Coherent and Yacc, there was a guy in
Massachusetts who sold Unix-tool lookalikes; I don't remember his name.
We were suspicious and checked his binaries against our source--bingo!
At the same time, our patent lawyer happened to be negotiating
cross-licenses with DEC. DEC had engaged the very plagiarist as
an expert to support their claim that AT&T's pile of patents didn't
measure up to theirs. After a day of bargaining, our lawyer somehow
managed to bring casual conversation around to the topic of stolen
code and eventually offered the suspect a peek at a real example.
He readily agreed that the disassembled binary on the one hand must
have been compiled from the source code on the other. In a Perry
Mason moment, the lawyer pounced: "Would it surprise you if I told
you that this is ours and that is yours?"
The discredited expert didn't appear at next day's meeting.
The lawyer returned to Murray Hill aglow about his coup.
The product soon disappeared from the market.
Doug