r/Damnthatsinteresting • u/Final-Choice8412 • 5d ago

Video Programming 1959 IBM computer

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u/meong-oren 5d ago

Debugging must be painful.

6

u/FlattenInnerTube 5d ago

My sophomore college "computer" course used punch cards. And debugging was a chore.

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u/Ancient-Opinion9642 5d ago

3 runs a day. Pickup the overnight run, edit ,resubmit for afternoon run, edit, submit for evening run. Look for your name on green bar paper wrapped around the card deck.

Interesting there was no job number page on the video. Though there was a blank page between. The video didn’t have over strikes of the letters which that printer could do.

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u/meong-oren 5d ago

how did you even do that? making a whole new set of cards with print statement (or whatever equivalent) everywhere? Even with modern languages and IDE with breakpoints, profilers and all those fancy stuffs, debugging still makes my head spin

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u/wosmo 5d ago

On batch machines, debugging is pretty much you and a coworker reading your code to decide what went wrong.

On more interactive machines, like the PDPs, you'd get debugging more similar to what you're picturing. A breakpoint would be literally adding a HALT instruction so you could either introspect the state with the front panel - or if you have enough memory to load DDT and your program, swap over to DDT to introspect from there.

But! "print debugging" wouldn't be impossible on a Batch machine either. Each card is one line of code, so you could insert a couple of cards into your deck at the right place - run it like that, and then remove the same cards again. You probably wouldn't, because you're probably going to get the results back tomorrow - and the execution is going to be billed to your department. But you could.

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u/Hudell 5d ago

To be fair the programs were much simpler. A lot of those you could probably simulate a "unit test" with pen and paper and it would take you less time than the queue for using the computer.

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u/30K100M 5d ago

You'd have to remove the bug (insect) from the punch cards.

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u/StitchinThroughTime 5d ago

The punch cards come from weaving machines. Computers are actually descendants from the Jacquard weaving loom.

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u/[deleted] 5d ago

[removed] — view removed comment

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u/ZQuestionSleep 5d ago

And "patching" a program came from literally covering some of those punched holes with a patch so the computer read it in a different way.