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Home-Built Relay Computer Clicks & Clacks on the Wall

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Max The Magnificent
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Re: Relays -- hah, how about this...
Max The Magnificent   8/6/2013 4:17:25 PM
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@IJD: A couple of years ago I was talking to a Russian (now working for an Israeli company) who had worked on a pneumatic computer used to control a Russian nuclear power station.

I'd heard about pneumatic logic being used to implement small control functions, but not to implement an entire computer. Do you knwo of any pictures / specifications for this beast?

OldSchoolTwidget
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Re: Eniac days
OldSchoolTwidget   8/5/2013 11:54:34 AM
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A long time ago I had a pre-PC keyboard, I'm thinking it was from Burroughs, that had fairly mushy (no snap-action) keys.  They actually built in a small solenoid in it to give you a nice loud click for audible feedback, and a little vibration for tactile feedback, on each keypress.

IJD
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Relays -- hah, how about this...
IJD   8/5/2013 4:50:18 AM
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A couple of years ago I was talking to a Russian (now working for an Israeli company) who had worked on a pneumatic computer used to control a Russian nuclear power station. It was the size of a supercomputer, and was all built with pneumatic logic gates and ran off air pumped in by a huge set of fans which were so noisy that the operators had to wear ear protection.

Given the low reliability of the hardware the whole machine used redundant and error-correcting logic (3-way majority voting on *everything* IIRC, gate-level and module-level) such that failed modules could be hot-swapped *while the control program was running* with no effect.

Why do this? Bacause nothing is more rad-hard if something goes horribly wrong than a computer which doesn't use electronics, only AC power...

David Ashton
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Re: Drum cards rule!
David Ashton   8/4/2013 6:08:16 PM
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Doubt it was exactly the same course, but I think in that era most computers were shared with punched card input.  It was lots of fun.  I'd just discovered biorhythms (remember them?) and as an (unofficial) exercise wrote a Fortran program to print them out.  Obviously doing graphs on text-based printouts wasn't that easy, but I got it working pretty well.   I was tweaking something and did the (for me) inevitable - forgot to close a loop.  When I went to get my printout (which was usually about 3 or 4 sheets) I had half a ream of fan fold 132-column paper waiting for me with my biorhythms for the next 50 years...and a VERY stern talking to from the head operator (especially as it wasn't set classwork).  If nothing else it taught me to check my loops VERY carefully in future.

Tom Murphy
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Re: Click & Clack
Tom Murphy   8/4/2013 4:58:03 PM
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Me, too, David.  But just barely.  I used them in a statistics class at UCSD back in '72. I remember we had to wait to do our class work at night because the serious engineering students had claim to the big computer during the day.  My relatively simple statistics problem took about an hour to run. Today, we could all probably get a lot more done sharing a smartphone. ;-)

Speaking of punch cards....some San Francisco trivia;  I once heard the four Embarcadero Center office buildings were designed to look like punch cards standing on end. I think of that every day as my ferry pulls into the embarcadero.

kfield
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Re: Drum cards rule!
kfield   8/4/2013 11:47:18 AM
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@Davidashton I took that same Fortran course! I remember the agony of waiting for the results and crossing my fingers that I got all the coding right!

betajet
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Re: Drum cards rule!
betajet   8/4/2013 9:19:42 AM
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Yep, that's a drum card.  Wikipedia calls them "program cards", but we never called them that because usually your whole deck of cards was a program.  Its main use was for setting tab stops, so you'd have one card for Fortran and another card for assembly language (tab stops for opcode, operands, and comments).  But it could also automatically skip columns, duplicate a column from the previous card, and automatically shift to numeric so you wouldn't have to hold down the numeric key when entering data.

   If you were entering fixed-format data such as "   .word  12345,67012,45670, ..." you could have the drum card automatically copy the ".word" and commas, skip to the correct columns, and shift to numeric so all you had to key in was the numeric values.  This was a very fast way to enter a lot of numbers, and I've yet to see a screen-based editor with similar capability.

David Ashton
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Re: Drum cards rule!
David Ashton   8/4/2013 4:27:13 AM
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@Betajet...Drum Cards...was reading more about these... seems they would enable you to put your statement numbers, contents etc in the right columns, and also limit what you could type in them......am I right?  The machine I used was used by a number of different users for different purposes and I don't think had a drum card used....but I could be wrong.   I can see it would be really useful if you were only entering (eg) Fortran statements.

David Ashton
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Re: Drum cards rule!
David Ashton   8/4/2013 1:51:22 AM
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@Betajet...no. just the usual punched cards done on a machine like this:

https://en.wikipedia.org/wiki/File:IBM_card_punch_029.JPG

I did a FORTRAN course once and you had to punch your cards out on the machine, then take them down to the computer centre (you learned to use 2 elastic bands the first time they fell apart :-) and they'd run it and you'd collect your printed output later.  Along with the wrath of the operators if you had an endless loop that chewed up valuable computer time.....

I take it you are talking about something like this:

https://en.wikipedia.org/wiki/File:IBMkeypunchDrumCard.MWichary.jpg

That would have been something else again....

betajet
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Drum cards rule!
betajet   8/3/2013 10:30:52 PM
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Did you program and use your own drum cards?


Personally, I am very grateful that I'm old enough to have come of age at the beginning of the microcomputer revolution and enjoyed the exciting "barnstorming" days before the "suits" took over.  Now it's all DRM and patent infringement lawsuits.  But there's still plenty of fun to be had in embedded design where you can still program at the bare metal, and in open source hardware and software where there's so little money to be made that the patent extortion entities find better targets.

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