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Hold on, let me turn my TeamOS/2 mug around so it can't see me type this... Firstly, NeXTStep came out in 1989, and had both preemptive multitasking and thread

Hold on, let me turn my TeamOS/2 mug around so it can't see me type this... Firstly, NeXTStep came out in 1989, and had both preemptive multitasking and threads, and OS X 1.0 didn't really improve on NeXTStep in that area at all. Secondly, while OS/2 1.0 had threads and preemption, it was text-only and had to run on IBM AT 80286 PCs so most of that technological might was wasted. It would be 1990 before it had a real GUI. And it would be nearly 1992 before OS/2 was 32-bit.

JdeBP 3y ago
It's eduction's choice of metric, not mine, and by that "multithreaded, preemptive multitasking OS" metric, OS/2 1.0 qualifies. eduction didn't say anything about graphics. Presentation Manager was available in 1988, by the way, not 1990. Petzold's book on it came out in 1989. First (and only) edition sitting on my bookshelf as I type this.