Early in my career I spent some years working at the biggest bank in Canada, they were (and still are) an enormous IBM customer. Hardware, software, consulting, and probably lots of other things I had no visibility into.
Beneath the countless layers of VMs and copious weird purpose built gear like Tandem and Base24 for the ATMs was a whole bunch of true blue z/OS powered IBM mainframes chugging through thousands and thousands of interlocking COBOL programs that do everything from moving files between partner banks all over the world, moving money between accounts, compounding interest, and extracting a metric shitton of every type of fee imaginable.
If you know z/OS there's work available until your retirement. Miserable, pointless, banal, and archaic legacy as fuck mainframe work.
Beneath the countless layers of VMs and copious weird purpose built gear like Tandem and Base24 for the ATMs was a whole bunch of true blue z/OS powered IBM mainframes chugging through thousands and thousands of interlocking COBOL programs that do everything from moving files between partner banks all over the world, moving money between accounts, compounding interest, and extracting a metric shitton of every type of fee imaginable.
If you know z/OS there's work available until your retirement. Miserable, pointless, banal, and archaic legacy as fuck mainframe work.
https://en.wikipedia.org/wiki/Tandem_Computers
https://en.wikipedia.org/wiki/BASE24
https://en.wikipedia.org/wiki/Z/OS