front panel display for a modern PC

[Chris Kennedy]

Chuck Guzis wrote:

> The front-panel thing seems to have been a cultural phenomenon.  

I suspect it has more to do with technology price-point.  I couldn't 
have build an operating system for an unmapped Nova in 1974/5 without 
one; "program load" was an uncommon option on earlier versions of the 
later 800/1200 family and even then required the switch register in 
order to get the device code to use. Bigger iron had the option of 
dedicated supervisory processors, but I doubt that the "affordable" 
(i.e., low five figures) minicomputers of the early-to-mid 70s could 
have really managed that trick without breaking the bank.

In my experience the front panel was also critical for figuring out what 
new and novel way the machine had broken.  MTBF was measured in months, 
and while a machine might have been too sick to load diagnostics it's 
surprising how much could be learned by poking at it through the front 
panel with a scope handy.  This proved true even in somewhat extreme 
cases, like the early S/200 with interleaved core in a memory expansion 
chassis that tended to fail pretty much any time the metal door to the 
machine room was opened or the 800 that we had to repair ourselves after 
the company with the maintenance contract refused to touch it (a current 
loop TTY with a hot chassis had worn through its data cable, dumped line 
voltage onto the loop, nuked the current loop/EIA converter, the mux, 
part of the bus interface on every board in the chassis and a chunk of 
both CPU1 and CPU2).

-- 
Chris Kennedy
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