On 8/1/23 15:44, Phil Smith III wrote:
Jon Perryman wrote:
The last Fujitsu mainframe is scheduled for 2030 and dropping all
support by 2035. Honeywell Bull GCOS and Unisys OS 2200 and MCP are
now x86 based. Are these mainframes or are they PCs?
PCframes? mainCs? It is hard to define rigorously, but as someone else quoted SCOTUS,
"I know it when I see it".
In common use, I'd argue (not very vociferously, I admit) that only IBM
machines-and maybe Fujitsus-are really mainframes: The others are just very
large computers. But this may be due entirely by the fact that I have to
explain to sales reps on a regular basis that our z/OS support means IBM
machines, not Unisys or whatever!
Fujitsu machines following S/370 architecture are mainframes. Amdahl
machines were definitely mainframes.
Look for channelized I/O, then other physical attributes (not just size,
not just the instruction set). It's not difficult, and it's not merely
cultural.
On balance, I encountered a Unisys machine, with the instruction set of
a much older system (which might have been a mainframe in its time)
which was definitely *not* a mainframe (because the contemporary box
just did not fit the class).
So Unisis machines not so much.
-- R; <><
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