[Leica] Back ar work

[Jim Nichols]

That's interesting, Herb.  I switched from EE to Aeronautical Eng. at 
the end of my freshman year, so I can't appreciate all of the electrical 
wizardry.  But one of the section heads working for me, an ME, had 
acquaintances with the requisite skills.  All I did was to provide the 
digital inputs and the calibration data.

Jim Nichols
Tullahoma, TN USA

On 6/26/2016 8:39 PM, Herbert Kanner wrote:
> Thanks Jim for the account of your PDP-8 encounter. You might be interested in how the four-part music was generated. Peter got permission to attach wires to four of the six sense lights and programmed the computer to turn on and off each light at the desired sound frequency. This gave a square wave (ugh) from each for the four wires. Then passing the resulting signals through an R-C circuit smoothed the square edges giving a musical quality. It all then went to a Heathkit amplifier. Of course, there was no control of dynamics.
>
> Herbert Kanner
> kanner at acm.org
>
> Question Authority and the authorities will question you.
>
>> On Jun 26, 2016, at 4:00 PM, Jim Nichols <jhnichols at lighttube.net> wrote:
>>
>> Thanks for the memories, Herb.  My first encounter with a mini-computer was, I believe, a PDP-8, a descendant of your original.  It arrived as a part of the fuel control system for a turbine engine test, and, when the test ended, our Plant Engineering "hackers" looked for other applications.  We started with the two critical pressure measurements needed for an accurate Mach number calculation during operation of the 16ft. Transonic Wind Tunnel.  By using the ratio of static to total pressure and the corrections determined during the wind tunnel calibration, the PDP-8 gave us real-time Mach number, displayed on small B&W TV monitors in front of the various operating personnel.  Things really developed from that small start.
>>
>> Jim Nichols
>> Tullahoma, TN USA
>>
>> On 6/26/2016 5:45 PM, Herbert Kanner wrote:
>>> My mail program went nuts last week. Twice I sent a rather long piece of mail describing the circumstances around a Gallery picture and each time the mail went into a black hole and the text had to be composed again. This time I'm being smarter and writing and saving it first in a word processor.
>>>
>>> OK. Don't remember what I last posted re health, but I was in the hospital for over a week with congestive heart failure. Made a rapid recovery as soon as I got home, and after a couple of weeks, returned to volunteer week at the Computer History Museum.
>>>
>>> As a consequence of the loss of the Babbage Difference Engine, I rejoined the group that gives twice monthly demonstrations of a working PDP1 computer (vintage 1960), the first “mini-computer”, in fact, the manufacturer (Digital Equipment Corporation) coined the term.
>>>
>>> The PDP1 is about the size of three household refrigerators. It's turned on at the throw of one switch. It sold for $120,000. In the year it came out, the manufacturer donated one to MIT. One professor permitted “hackers” access to it from midnight to morning. This was before “hackers” became a pejorative term. One of those hackers was Peter Samson, who figured out how to make the machine play four-part music, and our demo inclueds the opening of a Bach fugue. The other, Steve Russell, largely wrote the code for the world's first video game, Space War, which later became an arcade game.
>>>
>>> When I arrived at the Museum a week ago Saturday, I found the PDP1 team in the cafeteria area enjoing a post-lunch bull session. I just had to take a picture. We were all wearing our uniform red shirts. Note the guy on the right; that's Steve Russell.
>>>
>>> http://gallery.leica-users.org/v/herbk1/L1000005_001.jpg.html <http://gallery.leica-users.org/v/herbk1/L1000005_001.jpg.html>
>>>
>>> Please look “large”.
>>>
>>>
>>>
>>> Herbert Kanner
>>> kanner at acm.org
>>>
>>> Question Authority and the authorities will question you.
>>>
>>>
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>>>
>>
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