8 Sep
1998
8 Sep
'98
12:14 p.m.
Microcomputer: a computer based on a single
microprocessor.
Almost ALL machines today use just a few chips (at most) in the CPU. The
days of little glue logic chips are long gone. Some S/390s, for example,
typically use only two chips in the CPU, and only for redundancy! Same
with the AS/400s.
Workstation: a computer designed to run Unix with a
bitmapped display.
Unix? What about other OSes? Even NT...
Minicomputer: a timesharing computer that can support
fewer than 100
simultaneous users.
Many minis do not timeshare - embedded control was and is a favorite duty.
PDP-8s were single user machines (yeah, I know about TSS/8, so keep
quite!), yet when someone says "mini", they instantly come to mind of many
people.
Mainframe: a timesharing computer than can support 100
or more users
simultaneously.
Many mainframe applications do not have lots of people online, all tapping
away at their terminals. Some of the big boxes do their best work when
everyone is sleeping.
I think the best definition for a "mainframe" is a machine designed not
for processor speed, but I/O speed (thus the use of channels - some
mainframe CPUs actually _idle_ under a heavy load, because the channels
are doing all the work).
William Donzelli
william(a)ans.net