halforcwarlockbabe:gameraboy1:‘How it works’ The Computer - A Ladybird Book by David Car

halforcwarlockbabe:gameraboy1:‘How it works’ The Computer - A Ladybird Book by David Carey, 1971Illustrations by B. H. RobinsonWhat the fuck are punch cardsOh! They’re incredible! They’re ridiculous! They’re one of the earliest ways to program computers that didn’t require you to rewire the whole entire machine!Way way back in the day, computers were a mess: in the 20′s and 30′s if you had a “computer” it was more like a dedicated machine that did a certain calculation, and if you wanted it to do a different one you had to set aside a couple weeks or months for a team of engineers and mathematicians to figure out how to rewire the whole thing to do your new task. This is a mess, and a nuisance, and so we eventually decided to make general-purpose computers that could run programs.Slightly less way back in the day (long before I was alive, this was the 40’s or so), computers weren’t a thing that you had access to. If you wanted to run a program on a computer (or feed it data), you wrote the program, first by hand, so that you could edit it and make sure you got it right, then you would carefully sit down at a card puncher and you would painstakingly copy your program by typing it in, which would punch out each a hole in the card corresponding to each character. Think like a typewriter with extra steps.This is an example of a typical punch card, specifically an 80 character one. It contains a fragment of a FORTRAN program that goes “Z(1) = Y + W(1)”. You can see it printed out on top. Each column is punched out to correspond to that text, and the computer can read from this card directly into memory. 80 character card means this can only store 80 characters of text, and since your program may end up running into the thousands of characters, you would punch DOZENS and SCORES and HUNDREDS of these things. Each one was punched with a sequence number as well, so that you could try and keep them in order (and so that if you did mix them up, the computer would know)Once you punched your cards, you would carefully box them up and take them over to your computer operator, who had the job of taking each person’s work, putting it into the machine, getting any results, and giving them back to you (usually the next day, maybe several days if it was a very busy university). Cards were used to store programs and data well into the 1960′s, after which point they were gradually replaced, first by tapes and then made completely irrelevant by the advent of multi-user computers, which could have many people working on them at once, writing, compiling and testing their code as they went.Punch cards in slightly different forms are fairly historically important even prior to computers, they were used before modern computers to control mechanical looms to weave patterns into fabric, and thanks to the way that they can be used in combination with cleverly designed rods to create a fully-mechanical searchable database, they were used by IBM and other early calculating machine companies to produce fairly advanced information storage tools. Nowadays no one uses them, and they’re mostly a curiosity for tech history geeks.There are still plenty of remnants of it left over: the typical computer terminal is standardized at 80 characters wide, some versions of FORTRAN still need you to leave space for the start of each punch card, and there are programs in use at major companies who do serious electrical engineering design that still make reference to punchcards in their error messages. Heck, there’s even a program on my computer for drawing what a punchcard containing some text should look like!punchcards!EDIT: here’s a lovely video where someone who actually used punchcards talks about them -- source link

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