• Registered: 2022-01-21
  • Posts: 382

Topic: Ancient IBM mechanical punchcard keyboard

This video is about a repair of a mechanical keyboard from an IBM mainframe. I understand from a short skim of the beginning of the video that it is about a keyboard used to punch IBM cards, where a visitor to the museum exhibiting the machine has pressed a key too hard.

What is interesting, especially to anyone au-fait with mechanical drawings, are the drawings of the parts and assembly of the keyboard shown in the IBM manual for the device. They are a dazzling display of technical artwork.

https://www.youtube.com/watch?v=ZWLptl0cKSc

Does anyone remember using these punch cards to input to a computer?  I had to do that for input to a Digital (the brand) computer used in our development lab. I believe I had to input a Fast Fourier Transform program in Fortran, or at least the data. Oh! for the days when I could make Fortran sing! I spent some time, not successfully and not in that lab, to write a Basic program to do the same thing

2 Reply by William (edited by William 2022-11-20 16:56:59)

  • Registered: 2022-01-21
  • Posts: 1,198

Re: Ancient IBM mechanical punchcard keyboard

I used punched cards a couple of times but I never typed them myself.

This was in the early 1970s.

Computer users had to write the desired text on forms that had 80 cells per row, and about 20 lines, and produce a collection of sheets numbered 1 of (total number), 2 of (total number), and so on.

These were handed in at a reception desk and staff keyboard operators keyed the text.

One got back a deck of cards and one's sheets all together with an elastic band around them together with the lineprinter output of a run of the program.

If I remember correctly that included a listing of the program.

I think the computer was an ICL 1900 series mainframe computer.

There were no lowercase characters.

A zero had to be written with a diagonal line through it to distinguish from a letter O.

There was a facility to resubmit a deck of cards, possibly with some removed, and folded coding sheets for extra cards placed within the deck at one or more places, all held together with elastic bands.

The staff member would then produce an updated deck of cards and the program run, and the cards, the coding sheet and any output returned to the user.

William

  • Registered: 2022-01-21
  • Posts: 382

Re: Ancient IBM mechanical punchcard keyboard

In Fortran as I remember it, as opposed to simple  Basic programs where each line had a unique number, only "pivot" lines were identified. If you dropped the card deck or got the cards out of order some other way - I guess the program would not run properly.
In any event, I don't think Basic was run on card input machines.

You obviously wouldn't get lines out of order with punched tape inputs.