Re: Multi-tasking..as a matter of interest..
'worked'. It might have done from a programming perspective, but it's an awful OS. Coming to Mac OS late (as at the time it was out it was ridiculously expensive, and almost no-one at any of the many customers we had used one), and comparing it to OS/2 (which I was using at that time period) it's a horrid mishmash of components which work extremely well (multimedia and colour support), and those that don't (multitasking, on any version of Mac OS - 7.6, 8.6, or 9.2. Also fecking resource forks and Mac compression standards are such a pain).
I'll grant that from what I can see OS X is hardly perfect either, but at least they stuck a fairly solid kernel underneath it (although, again, under any PPC version of OS X the spinning colour beachball appears more than you'd expect).
(To be fair, viewed from a modern perspective, OS/2 is also incredibly creaky. The latest versions only bring up to being mildly irritating)