Delete comment from: Ken Shirriff's blog
| 15. A CRT display was used for the console on
| the models 85, 91 and 195. (I suspect this was
| because CRT display technology had advanced by
| the time these later systems were built.)
It had nothing to do with CRT display technology
(advanced OR cheaper). In the case of the 360/91
(and 360/95) and the 360/195 (and 370/195), the
reason for a CRT operator console was speed; the
"printer" (and Selectric typewriter ball-based)
consoles were simply too slow for the fast CPUs.
The 91 (and 95) and 195 models still had huge,
control and indicator panels, but they were not
integrated with their CRT-based operator display
consoles. The 360/85 used an integrated system
console that incorporated both the CRT console
display and the indicator and control panel, but
the indicator panel section was small [like the
CRT console] and the control panel section was
very small (smaller than the one for the 360/30)
and integrated with the chassis that housed the
CRT display.
In other words, starting with the 360/85, they
stopped building huge "blinking lights" panels
that were so popular with executives, visitors,
and media photographers. The CRTs were needed
for message display speed, regardless of cost
(or technology), and computer rooms needed the
space occupied by the 6-, 7-, and 8-foot wide
blinking lights and control panels for actually
useful equipment.
The size of the control and display panels (as
distinguished from the actual "operator console"
on which messages were typed or displayed) was
merely a reflection of the internal complexity
of the CPU. The knobs, switches and blinking
lights were of essentially no use to the actual
computer operator (other than impressing visitors
and enabling one to observe patterns indicating
that the system was operating normally -- or not).
They were mainly needed by the IBM FEs performing
maintenance and running diagnostics.
The indicator panels for the 91 (and 95) and the
195 were huge simply because there was a lot that
needed to be displayed. The Model 360/85 was more
complex; an indicator and control panel for it
that used "discrete" lights and switches would
have been unacceptably huge, so they used the
"Microfiche Indicator Viewer" (part of the "System
Control Panel") instead. The actual 360/85 operator
console (the "Main Control Panel") housed the CRT
(which displayed messages issued by the operating
system, etc.) and the knobs, buttons, and switches
actually used by the operator (such as the blue
LOAD/IPL button and the Load Unit Address dials).
This 360/85 "System Control Panel" was also used
for the System/370 Models 165 and 168 (where IBM
called it the "IBM 3066 System Console"). As far
as I was able to tell in 1971, the 3066 was only
cosmetically different from the 360/85 "console."
Apr 8, 2019, 2:45:37 PM
Posted to Iconic consoles of the IBM System/360 mainframes, 55 years old