Sorry your browser is not supported!

You are using an outdated browser that does not support modern web technologies, in order to use this site please update to a new browser.

Browsers supported include Chrome, FireFox, Safari, Opera, Internet Explorer 10+ or Microsoft Edge.

Geek Culture / How do punched card readers work?

Author
Message
Libervurto
18
Years of Service
User Offline
Joined: 30th Jun 2006
Location: On Toast
Posted: 10th Oct 2009 07:40
Link
Very old school question here: I've been searching for how those punch cards worked but I can't find anything describing how the machine actually read the data from them.
Are any of you old enough to even know what I'm talking about?
This has been driving me mad and I can't figure it out. Does something go through the holes?

TGC Forum - converting error messages into sarcasm since 2002.
Back to top
Profile PM Email
NeX the Fairly Fast Ferret
20
Years of Service
User Offline
Joined: 10th Apr 2005
Location: The Fifth Plane of Oblivion
Posted: 10th Oct 2009 11:57 Edited at: 10th Oct 2009 11:58
Link
I have no idea, but if I was doing it I'd have metal balls that either get held in place by the lack of a hole and complete the circuit or fall down a few MM into the hole and break the circuit.



As for making them not fall out of the machine... springs?

Back to top
Profile PM Website
BatVink
Moderator
22
Years of Service
User Offline
Joined: 4th Apr 2003
Location: Gods own County, UK
Posted: 10th Oct 2009 11:58 Edited at: 10th Oct 2009 12:00
Link
they work on a binary system. The holes in the card generally allow 2 contacts to touch, and the combination of holes generates a byte (technically, it was less than a byte, 6 bits was common). each horizontal line is a byte, and the stream of attached cards, or the deck in other systems is your serial input.

Here's the impressive bit. While we're trying to create sorting algorithms in a few lines of code, here's the punch card equivalent. It keeps filling the bays and restacking them until they are eventually fully sorted. We used the one in our store room for making the tea on. No - I'm not old enough to have used these, but we had all the kit in storage behind the computer room.



EDIT - here you go, the IBM System 3 which was punch card driven - http://en.wikipedia.org/wiki/IBM_System/3

Back to top
Profile PM Email
JLMoondog
Moderator
16
Years of Service
User Offline
Joined: 18th Jan 2009
Location: Paradox
Posted: 10th Oct 2009 14:23
Link
My mom use to have to program punch cards at a hospital. She said the average program was around 1000 cards. She use to bring home boxes of them for me to look at. Crazy stuff.


Back to top
Profile PM Email Website
Jeff Miller
20
Years of Service
User Offline
Joined: 22nd Mar 2005
Location: New Jersey, USA
Posted: 10th Oct 2009 15:05
Link
It's not like from the Jurassic period. There are at least 3 forum members I know of who used these to program in Fortran in the 1960's, myself included. I still have some programs on these cards packed away somewhere. Most of the typing consoles would print the characters you were punching in along the top edge of the card. Program lines did not accommodate comments following the command, but you could scribble in your own, which was convenient.
Back to top
Profile PM Email
Mnemonix
22
Years of Service
User Offline
Joined: 2nd Dec 2002
Location: Skaro
Posted: 10th Oct 2009 17:07
Link
My mum used to work for a bank typing punch cards using COBOL and FORTRAN. She has tried to explain it to me a number of times but it always confused me

Mnemonix
Back to top
Profile PM Email Website
Back to top

Login to post a reply

Server time is: 2025-05-25 20:06:56
Your offset time is: 2025-05-25 20:06:56