out-of-mainstream minis
mark at markesystems.com
mark at markesystems.com
Mon Jul 6 17:34:25 CDT 2015
OP (about the 68000 box) here – thanks for all the informative comments!
I did spend some time using the 68010-based Apollo workstations, and as I understood it they were equipped with two processors, one shadowing the other, because not enough information was saved to completely restart an instruction – particularly a block transfer – if a memory paging operation was required. Apparently the 68020 somehow fixed this problem. (The 68008, BTW, was just a 68000 with limited address space and an 8-bit data bus. It was primarily targeted at deeply embedded systems, not “general purpose computing” applications.)
Thanks for the clarification about V7 Unix not requiring demand paging; this makes complete sense, since it was never mentioned in any of the documentation I read. And yes, it it was Unix V7, not “System 7” (sorry, it was a while ago...).
Thanks for the pointer to the Convergent Technologies boxes. This wasn’t them (the case was different: it was black, and horizontal-profile), but the functionality looks very similar; they could easily have had the same motherboard or other guts. Also, I forgot to mention in my original post that there was a 5-1/4” floppy on this thing, too.
~~
Mark Moulding
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