How do you boot a computer from punch cards when the computer has no operating system and no ROM? To make things worse, this computer requires special metadata called “word marks” that can’t be represented on a card. In this blog post, I describe the interesting hardware and software techniques used in the vintage IBM 1401 computer to load software from a deck of punch cards. (Among other things, half of each card contains loader code that runs as each card is read.) I go through some IBM 1401 machine code in detail, which illustrates the strangeness of the 1401’s architecture and instruction set compared to a modern machine.
I simply cannot imagine what wizardry these newfangled computers must’ve felt like to the people of the ’50s, when computers first started to truly cement themselves in the public consciousness. Even though they’ve been around for twice as long, I find a world without cars far, far easier to imagine and grasp than a world without computers.
As someone who collects older computers, i just find it fascinating just how advanced computers have come. If you compare them to something like the motorcar, cars have barely changed at all since the 1930’s. Sure, modern ones have more bells and whistles, but a car from the 1930’s runs and drives nearly the same as one from the 2010’s
However, plonk someone in front of a computer from even the 1980’s and i bet they’d be lost on how to use it. Go further back, like the late 60’s and early 70’s and you’d struggle to switch it on, let alone get a command prompt. Going further back to the 1940’s and 50’s,. and you’re on the cusp of the computer revolution, and the things were made from relays and tubes, totally unrecognisable to most people today.
There is something i’ve learned from studying mainframes and minicomputers, and the tech revolution from the 40’s to the 90’s though. And that is that machines today have kind of stagnated. Even 20 years ago, there was at least half a dozen ISA’s in common use, with a lot of big tech companies even designing their own architectures (DEC, HP, IBM, Motorola just to name a few). However, today, everyone has standardised on ARM and x86, and to be honest, this isn’t very good. Big developments in architectures have stagnated, performance improvements are marginal, and the need to upgrade computers regularly has largely become a thing of the past (a good thing!). But with essentially a monoculture in computing, we have the same issues as a monoculture in agriculture, pests and disease (malware, viruses) can affect wide swathes of the technology sector, rapidly spreading to nearly every piece of computing equipment deployed in the world.
I think i got a bit off-track here… Old computers are cool though, and everyone should own at least something from the 80’s, like a C64 or Sinclair spectrum.