Archived posting to the Leica Users Group, 2016/06/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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. >>> >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >>> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >