The 'older than dirt' crowd here will appreciate this

[Snowhog]

I'm not one of the 'older than dirt' crowd.

[die.boer]

eish , i'm old , but not THAT old

[die.boer]

just for interest sake , here's how it all worked back then lol (credit to me AI)

1. The cards were the program
The paper form in your picture was the planning sheet. A programmer would write the instructions on it, and a keypunch operator (sometimes the programmer themselves) would use a special machine to punch holes into stiff cards.
-Each card typically held 80 columns of data.
-Each column represented one character, encoded by a particular pattern of holes.
-The computer read those holes using a card reader.

The cards weren't merely a way to store the program on paper. They were the actual input medium from which the computer could read the instructions.

2. One dropped deck could ruin your day

Imagine your program consists of 500 punched cards, stacked in a particular order.

Now imagine dropping them all over the floor. 😬

The computer needed the cards in the correct sequence, so programmers often numbered cards or used identification fields to help restore the order. The Identification Sequence column at the far right of your form was designed for that sort of purpose.

A shuffled deck could mean hours of sorting before you could even try running your program again.


3. Every column had a job


Look closely at the form in the picture. The headings aren't just decorative — they tell you where different parts of the assembler instruction belong.

1–8	Name or label
10–15	Operation (the instruction)
16–71	Operands and comments
73–80	Identification or sequence number

These are the normal conventions for the IBM System/360 assembler form; the precise fields have their own rules. Column 72 was used for a continuation indicator when an instruction needed another line.

The interesting part? You couldn't necessarily type an instruction wherever you felt like it. The column positions had meaning to the assembler. It was a bit like programming inside a spreadsheet, except the computer expected you to get the layout right!

4. There was a person between you and the computer

In many computing departments, programmers didn't punch their own cards. They submitted their completed coding sheets to a keypunch operator, who entered the code using a keyboard-driven punching machine.

The process often looked like this:
1. Write the code
The programmer fills in the coding form by hand.













2. Punch the cards
An operator transfers each line to a physical card.













3. Submit the deck
The complete program is prepared for processing.













4. Collect the results
The computer processes the job and produces output, often on paper.


Some departments also used a second keypunch operation to verify the cards, catching typing errors before the program reached the computer.

5. Debugging could take hours over one character


Today, you might edit a line, press a shortcut, and rerun your program within seconds.

With punched cards, a mistake might require identifying the faulty card, punching a corrected replacement, putting the deck back in the correct order, and submitting the job again.

And there were two kinds of mistakes:

• Syntax errors: the assembler couldn't understand an instruction.
• Logic errors: the program ran, but did the wrong thing.

The second kind could be especially frustrating because the computer might happily process hundreds of cards without telling you that your program's logic was nonsense. 😂

The delay between submitting a job and receiving its printed results made debugging a much slower process


6. Computers often worked in batches


A programmer didn't necessarily sit in front of a screen and interact with a running program.

Instead, a deck could be submitted as a job to a mainframe. The computer would process jobs according to the site's scheduling and workload, and the programmer would collect the output later.

At some university computing centres, users submitted programs in the evening and received printed results the next day.

Imagine discovering a tiny typo in your code after waiting overnight. You could lose an entire day to one character!

7. The cards were reusable — but not like a USB stick

Punched cards weren't inherently one-use items. They could be read repeatedly, and a card deck could be stored and reused as needed.

If you wanted to modify a program, you often only needed to replace the cards containing changed instructions rather than punch the whole program again. Of course, you still had to preserve the correct order and keep track of which version you were using.

And yes, some places used differently coloured cards to distinguish things such as program source, data, and job-control instructions.


8. The coding sheet itself was surprisingly practical







Here's a particularly neat detail about the image: the long form was designed so that one horizontal line corresponded to one punched card. The grid aligned with the card's columns, and the form included space for instructions to the keypunch operator.

The shorter form shown below it served the same basic purpose with a different layout. These weren't just stationery; they were part of the programming workflow.


One final mind-blowing fact
Punched cards weren't invented for computers at all!

They were used to control Jacquard weaving looms in the early 1800s. Holes in the cards controlled which threads were raised, allowing intricate patterns to be woven automatically. Later, Herman Hollerith adapted punched-card technology for processing data from the 1890 US Census, and the technology eventually became central to computing.

So the technology that helped make computer programming practical grew out of a much older idea: telling a machine what to do by giving it a physical pattern of instructions.

And here's the thing I find especially interesting: those old cards helped establish conventions that outlived them. The familiar 80-column limit influenced terminals, text editors and command-line environments for decades.

Even today, when you're working in a Linux terminal, you can still encounter traces of that old world.

From weaving looms to IBM mainframes to your Kubuntu terminal — that's quite a journey for a piece of cardboard! 😄

[life0riley]

just for interest sake , here's how it all worked back then lol...

Thanks for that die.boer!

That description and photos triggered my memory and took me back in time. My father told me about this when I was a kid. I recognized the cards. He told me about the tape drives and the large room filled with computers. He was in the financial department, but he was very familiar with the process.

[Qqmike]

At some university computing centres, users submitted programs in the evening and received printed results the next day.
Imagine discovering a tiny typo in your code after waiting overnight. You could lose an entire day to one character!

Yep, exactly right. Well, it isn't "right," but it is "correct"!
Don't ask me how I know that.

Some programs had many hundreds of cards.

[skyfishgoo]

loading any kind of useful FORTRAN program took forever, and god forbid you get one dot or one card out of place and have to do the whole thing all over again.

[oshunluvr]

I was punching cards on that very same machine in 1977!!!!

[Qqmike]

Thinking about this ...
I remember the key was to have a good guy running the computer center,
someone who could help you quickly spot a bad card,
someone who could helpfully schedule jobs to keep everyone going,
someone who might even re-punch a card or two for you if that's all it took to run your deck through.

[kc1di]

remember paper tapes

[Snowhog]

And now, a trip along memory lane (Pun not intended). Timeline of Computer History

[die.boer]

And now, a trip along memory lane (Pun not intended). Timeline of Computer History

interesting stuff !

[Qqmike]

Yeah, the computer history was good. Thanks, Snowhog. 👍