[vcf-midatlantic] What we can learn from vintage computing

Herbert Johnson hjohnson at retrotechnology.info
Thu Dec 22 18:45:38 UTC 2022

Jeff Jonas discussed the IBM 1130 front panel. He noted well-labeled 
controls and computer operations to the single instruction or cycle or 
clock. It's good information. But Jeff ends with this:

> All that was lost with the microprocessor :-( All the data busses and
> registers are internal with no pins, thus relying on a monitor to
> view/alter registers. That's the glory of REAL font panels: they're all
> HARDWARE, they can't lie :-)

The MITS Altair 8800, the IMSAI 8080, the MITS 680, the Ithaca 
Intersystems DPS-1; all supported MITS-class front panels. The earliest 
1802 computers, same era, had a byte-level, single clock/instruction 
front panel (and little else).

Home-built early 8008 and 8080 systems, often included front panels. 
Terminals were expensive, memory was limited, and front panels helped 
debug the hardware. People looking back today, don't appreciate the 
limited resources (and limited wealth) during 1970's micro computing.

MITS people may not have known about the IBM 1130 front panel. But 
certainly, Ed Roberts knew about the Data General NOVA, which sat in his 
office, and which has a front panel. (David Greelish interview with 
Roberts.) The MITS front panel, like the Nova, permitted single-cycle 
and single-instruction operation of the 8080 microprocessor. It could 
not display registers, those are internal to the 8080.

So, front panels were not "lost with the microprocessor". They simply 
fell out of favor, by the late 1970's. Briefly: as microcomputers became 
more powerful and hardware stabilized, software debugging was cheaper 
and preferable to hardware debugging. Computers designed for the office 
and home, were styled like office equipment. I lived through the era, 
it's hard to prove why something stopped happening.

On "hardware panels can't lie". They can fail too. And some devices 
won't run at toggle-clock speeds. Problems may not manifest on a 
front-panel if they are intermittent.

Front panels are a tool, like other tools they have utility or not. 
Should I say, "all that was lost, when personal computers became 
commonplace"? Things change, sometimes there's reasons.

Regards, Herb Johnson

Herbert R. Johnson, New Jersey in the USA
http://www.retrotechnology.com OR .net
preserve, recover, restore 1970's computing
email: hjohnson AT retrotechnology DOT com
or try later herbjohnson AT comcast DOT net

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