The TX-2 at Lincoln Labs had an oscilloscope driven by the following
inputs: the y axis had 0 at the top and had the program counter mapped into
it so that the highest address in the machine put the beam at the bottom of
the scope. The x axis bias to the right was made proportional to the
distance of the jump. Thus, the scope showed the dynamic nesting of the
executing program. The most executed loops of course showed up brighter. It
was pretty sweet to look at.

Cheers,

Alan

------

At 5:54 PM -0800 5/11/00, demiourgos at smalltalk.org wrote:
>On Thu, 11 May 2000, Peter Crowther wrote:
>
>>
>> > From: Dan Ingalls [mailto:Dan.Ingalls at disney.com]
>> > (now don't get me started on printer music ;-).
>>
>> The system console on the 1900 series had a built-in speaker that clicked
>> whenever a particular instruction related to a context switch was executed.
>> We had a program that would play the Close Encounters alien theme on the
>> speaker... if you ran it at a sufficiently high priority (and irritated all
>> the users).
>
>[snip]
>
>When time-sharing came into vogue, I missed having the box right there
>so you could use it to debug programs.  Of course, today we have PCs
>and workstations.  One of the things which interested me were experiments
>people proposed to either wire the address lights on the console into an
>oscilloscope with a bit of circuitry, or to drive an audio system.  In either
>case, the idea was to learn more about the program being executed by
>seeing or hearing patterns.  Initially I imagine, this would be pretty tough.
>But one could learn, I guess.  A bit like the displays in "The Matrix", albeit
>at a lower bandwidth.
>
>  --jtg
>
>__________________________________________________
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