They didn't copy directly, they just re-implemented from memory. I worked for Digital right out of college at the "DEC West" site off 520. A number of my co-workers REALLY hated Microsoft. Swore up & down they had colleges who had seen NT source code when they started working together with Microsoft on "Wolfpack" server clustering that they were using the exact same terms & constants (e.g. structs for system values were identical). Dave Cutler & his crowd were not popular. That $60M - $100M was payoff money to avoid a very public & very nasty copyright suit. And back then, $60M - $100M was considered real money.
Did they really? I thought MS just implemented their own version of the tech and was accused of violating patents. Did they actually steal IP?
Reading the Wikipedia article, it's not really clear what happened. Looks like MS review Stac code during licensing talks, but there's no mention of accusations of code theft. Then there's discussion of patent violation lawsuits and payoffs going both directions.
