Front panel switches - what did they do?

Al Kossow aek at
Tue May 24 12:00:20 CDT 2016

On 5/24/16 9:34 AM, William Donzelli wrote:

> The demise was really about money. All those lights, switches, wiring,
> metalwork, etc. for a full panel was EXPENSIVE.

And the functionality could be replaced by scan chains connected to a small computer
so you still had all the visibility w/o the expense. Amdahl mainframes and the Xerox
Dorado come to mind.

When hardware was BIG, it was easier just to put major controller registers on panels
above the logic, ala DEC peripheral controllers, or on maintenance panels that the
customers would never see (Burroughs, Univac)

Something else that control panels could do is single step or single cycle a CPU.

A few PDP's had a knob that would let you vary the processor clock rate (from memory,
the PDP-6, 7, 10 and 12)

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