Re: 80386 vs 80286
Thw 286 lacked the virtual86 mode (used to run DOS in protected mode by Windows) and couldn't exit protected mode once entered it (but forcing the CPU to a warm reset).
The 286 could address 16MB of RAM, and it was a fairly amount then. Most 386s (and I guess a lot of 486s) never saw that much RAM - despite their 32 bit address space.
What the 286 couldn't do easily was running both many real mode DOS applications at the same time of any protected mode OS. The tricks used brought the 286 back to the plain, single thread, real mode, while Virtual 86 still runs in protected mode and can "emulate" multiple, separate real mode processors.
Thereby there was not much interest in developing an OS that couldn't run the large number of available DOS applications much better than DOS itself. A true 286 OS - even without a GUI - would have allowed multiprocessing, but application would have need to be rewritten for protected mode (and most DOS applications were written to directly access the hardware also). LAN Manager 1.x, IIRC, was written for 286 protected mode - but it was just a network OS offering no dektop capabilities, and no need to run DOS applications. Microsoft had Windows run on 286, but Windows itself took off really with version 3 and its applications, when 386 were already affordable enough, and there were really no reason to run it on the older 286.
Your informations about the Pentium Pro looks largely innacurate.
Biting the hand that feeds IT
