Date: Tue, 2 May 2000 02:00:49 -0700 (PDT) From: "Rodney W. Grimes" <freebsd@gndrsh.dnsmgr.net> To: chad@DCFinc.com Cc: dr@dursec.com, kpielorz@tdx.co.uk, djb@ifa.au.dk, smp@csn.net, chat@FreeBSD.org Subject: Re: hlt instructions and temperature issues Message-ID: <200005020900.CAA04147@gndrsh.dnsmgr.net> In-Reply-To: <200005012233.PAA18008@freeway.dcfinc.com> from "Chad R. Larson" at "May 1, 2000 03:33:57 pm"
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[Moved to -chat, left others on thread in cc's, they may want to drop out though.. also I am not on chat, so I'll loose the thread if someone chops the cc's] > As I recall, Rodney W. Grimes wrote: > > Right along with the chain breaking/hammer bank smoking code for the > > 1403 printers.... basically a very specific sequence of lines with > > very special character sequences could cause 1/3 of the hammer bank to > > fire every 14uS or so, do that for more than 10 cycles or so and you > > could litterly break the print character chain. De-optimize it for > > chain breaking and run it for 10 minutes and you would start smoking > > the hammer coils.... > > Ah, yes. I had one that would play "The Iowa Fight Song" (I was > working for Collins Radio in Cedar Rapids at the time--circa 1969). > > Worked best with a single sheet of paper, and the paper thickness > set for 6-part forms (very rattley). And the feed clutch > open, so you could use "line feed" as a drum-beat. We had a printer > controller (built by Collins, the 8401 I believe) that would allow > you to gang printers, in case you needed more than 6 copies. Get > five or six printers going and you could hear the song all over the > building. I seem to remember one of my cow-workers wrote "On > Wisconsin" as well. Thats a new one on me! Or at least the use of a printer to make ``computer music''. We use to do that with PDP-8's and an AM radio, you did diffent pitches by loop length and device type. I've heard bach done on a pdp-8, pretty impresive for a 100kHz computer :-O. > > But shattering the chain was pretty spectacular. You'd want to be sure > the covers were down or someone could get hurt. The IBM CEs loved us. Yea, them little slugs go every which way. > > Sometime I should tell you about making the Bryant disk drives walk > across the floor... Easy.. done that with lots of disk drives... ever see a 5MB RK05 rack mount unit pop itself out of the cabnet... I was lazy and those things where heavy! Just unlatch it then run this... n=#cylinders while true do; seek 0; for 1 to n seek n; done ; And when your done with the head alignment and don't feel like shoving it back in by hand run this... n=#cylinders while true do; seek n for n to 1 seek n; done ; Or was that the other way around.... any way most drives can be made to move considerable distances with this type of code, even a modern IDE drive on sitting on a piece of glass or other low friction surface can be made to move this way. > > -crl > -- > Chad R. Larson (CRL15) 602-953-1392 Brother, can you paradigm? > chad@dcfinc.com chad@larsons.org larson1@home.net > DCF, Inc. - 14623 North 49th Place, Scottsdale, Arizona 85254-2207 > -- Rod Grimes - KD7CAX @ CN85sl - (RWG25) rgrimes@gndrsh.dnsmgr.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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