Today, a programmer just needs to open an editor, type a few lines, press “Run” — and he immediately sees the result. Now imagine: you are a programmer in the 1960s. You have no screen, no keyboard, no Stack Overflow. All you have is paper, a pencil, and a stack of punched cards.

Code — on paper first

Programmers first wrote code by hand — carefully, in special notebooks or on forms with templates. This was their “IDE”. Made a mistake? Rewrite the page. Comments were made by hand in the margins, flowcharts were drawn with a ruler.

Punched cards: physical code

Each line of the program was turned into a separate punch card — a piece of cardboard with holes punched in strictly defined places. A special punch was needed to turn handwritten code into “machine code”. One wrong symbol — and the program broke. One line per card. The order is critical. A stack of hundreds of cards falls — and that's it, start over. Some programmers wrote line numbers in pencil in the corner — just in case.

The "compiler" was in another building

To test the code, you had to hand the cards over to an operator who ran them on a room-sized computer. The queue could take hours. And if there was an error in the code, go back, fix it, print the card again and put it back in the queue. And so on — day after day.

In your head — a debugger and a call stack

Since there was no time or resources, most errors were caught in your mind. Programmers memorized the syntax, imagined the code working step by step and carefully calculated resources. No logs, no tracebacks. Just logic, attention and paper.

Why is this important

It sounds crazy by the standards of the 2020s, but this is how the foundations of the programming we use today were laid. Those who wrote code by hand created the first compilers, operating systems, databases. They couldn’t “google” an error. They had to understand how each instruction worked. The next time your IDE prompts you for syntax, and your linter fixes spaces, remember that there was a time when all this was done by hand. And not because they were superheroes. But because there were no other options.