Comment by bombcar

Yeah, mainframe coding is much closer to "code NASA runs on spacecraft" than what most people consider coding to be today. And the level of hardware support (mainframes are basically redundant on everything) and software support is unheard of. Consider that these things are so integrated into major banks, etc, that even minutes of downtime would cost millions upon millions, and think of all the things you can spend millions on to reduce the chance of it happening.