how did we make the first computer operating system if we didn’t have computers to make them on?
In: Technology
Very early computers didn’t have an OS. You’d just run a program directly. (Also applies to some later computers, for example game consoles through the mid-90’s typically ran games as programs directly from ROM cartridges.) So I’ll rephrase your question as “How do you get a program onto a computer if you don’t have any running program on that computer, or any other?”
Three main ways:
– (1) Toggle switches. A computer has memory unit and CPU, plus a bunch of connecting wires called “bus lines”. Build switches that let you manipulate the bus lines directly. The memory does what the bus lines tell it. Have a human operator switch off the CPU, then switch the bus lines to input your program. One bit at a time.
– (2) Hard wired. Instead of having a memory unit that can store anything you want, instead hard-wire its responses to all possible inputs (addresses), to represent the program you want it to run. For e.g. the Apollo guidance computer, some worker had to [weave wires by hand](http://www.righto.com/2019/07/software-woven-into-wire-core-rope-and.html).
– (3) Punch cards. Mechanical, or mechanical / electric hybrid, machines had been used to process punch cards for decades, most famously starting with the [1890 census](https://en.wikipedia.org/wiki/1890_United_States_Census#/media/File:1890_Census_Hollerith_Electrical_Counting_Machines_Sci_Amer.jpg).
Punch cards are particularly fascinating. Basically you have a piece of cardboard, and a machine with electrical wires that try to make contact through the cardboard. Based on which wires make contact, the electrical part of your device “knows” if there’s a hole at a specific spot. Put maybe 100 or so spots on a cardboard. Then you can build specialized tools or simple mechanical machines to help people punch meaningful patterns on the cards efficiently.
Make feeder / hopper mechanisms to support working with large decks of cards. It’s an electronically accessible mass storage medium, that was already decades-old mature technology by the time the first computers came on the scene. If you were inventing one of the first computers, you could simply *buy* a typewriter that converted keystrokes into hole patterns on punch cards.
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