There are tons of programs related to moving money from one place to another, all written in COBOL or Fortran at the time when men wore hats and smoked indoors.
First they were kept alive by cobbling together new hardware to keep the old monster running. Then they were moved to virtualized environments that emulated the original hardware with all its weirdnesses and glitch.
These are the zombies we're talking about. The useful living dead. We feed them their pound of flesh every now and again in the form of coders who can still speak the ancient incantations, but otherwise we keep them in the basement toiling away.
We don't touch them because we are too afraid. No one dares to take the responsibility of rewriting all that code that still works, no matter the cost.
And what's the alternative? We rewrite the whole stack in Java/C++/C# this year, and in 20 years we rewrite the whole thing again in Rust? That really doesn't seem like an improvement to me.
Same thing happens everywhere. Fire code, regulations and other best practices improve and we don't use asbestos, leaded pipes or non-grounded electricity to build houses anymore, despite how good and convenient it was 30 years ago.
Now you could still live in such an old house today and be happy but the moment you remodel and tear down that asbestos wall you will need to sanitize the whole thing from dangerous particles. Same thing with old programming languages, they don't have the same guard rails as today so once you start tearing up old dust there could be invisible demons awaiting, especially if done by people with limited experience in such environment.
The alternative would be to keep the code fresh. If you let it stagnate, the hidden knowledge on how and - more importantly - WHY it does things gets lost.
If you write it once and fire all the programmers, every update is a huge undertaking with immense risks. But if you keep reiterating and refactoring it slowly over time, the code stays fresh and the knowledge isn't lost.
You might change the language stack for the whole product during the iterations, maybe just use a fresh stack for a part of it. Maybe keep the old tech, but make it more readable and easier to integrate with other systems.
Anything travel related as well. Somebody in the 1980s thought that being able to read your order with just your surname as a password was a good idea. Or that passwords have to be 8 character maximum, no profanities or common words, and they can't have Y or some other characters since you could not have dialed it on a specific model of 1980s phone. I haven't touched a GDS for the past 10 years or so, but they are out there, probably still on mainframes as well.
First they were kept alive by cobbling together new hardware to keep the old monster running. Then they were moved to virtualized environments that emulated the original hardware with all its weirdnesses and glitch.
These are the zombies we're talking about. The useful living dead. We feed them their pound of flesh every now and again in the form of coders who can still speak the ancient incantations, but otherwise we keep them in the basement toiling away.
We don't touch them because we are too afraid. No one dares to take the responsibility of rewriting all that code that still works, no matter the cost.