I recall reading a story about IBM systems programmers writing code for zSeries mainframes. A thing that stuck with me was a discussion about code at the core

I recall reading a story about IBM systems programmers writing code for zSeries mainframes. A thing that stuck with me was a discussion about code at the core of this work; virtual memory, IO subsystems, etc. The engineer reflected on how the code he was writing would still be in production when he died. It would survive evolution of the hardware for many generations; they designed it to do this and provide permanent APIs to relying code. I wish I had a copy (..link) to that article. Byte, Computer Shopper... something like that. There are a few pieces of code I wrote in the 90's (in C) that I know are still in use and may survive a few more decades; as long and the companies that I worked for at the time are still in operation anyhow.