"Only" In the context of that time, "only when you're trying to achieve CPU concurrency" was meant as "only if you're doing something exotic" (though it wasn't

"Only" In the context of that time, "only when you're trying to achieve CPU concurrency" was meant as "only if you're doing something exotic" (though it wasn't as exotic as Osterhout thought - I'd already been working on MP machines for years). In the context of this time, it means "only" in an extremely common case. The difference matters. People who read the presentation without putting it in historical context will be misled, even if Osterhout weasel-worded his conclusions because he kind of knew he was wrong already.