I got woken up by a work phone call because a bank couldn't generate a text file on time
Anyone that tells you mainframe systems are reliable is lying to you or has been frozen since the 80s
They were less reliable then, too. Reliable systems are a myth, only redundant backups exist - and there's always a human getting an inconvenient call-in at some point in a 24/7 uptime reliability service. Real systems engineering is about distributing the expected failures such that the likelihood of chained failures leading to catastrophe is minimized. If it's done right, the humans at decision-required stages of this backup process will also have backup humans and be well rested and well compensated. If not... That's more usual, sadly. Stupid profit motive, you go squish now.
Have failsafes, fallbacks and more people as backup?
That sounds expensive and not very Capitalism of you.
an aside about mainframes and regulations:
plane ticketing and scheduling systems are abysmal, and many are on mainframes and minicomputers.
they all know it; they all want to upgrade. But they won't. not until regulations pass.
Whoever decides to spend millions and millions on the migration would have their end product reverse engineered for a fraction of the cost. They'd fall behind in a cutthroat, close market, which means someone else will buy you as you fall behind because you need money to make money.
banks are probably the same, so greedy and doing so well that none of them can afford to not be absolute dogshit if you aren't coming to them for rich people reasons like big big loans or financial planning.
