I want to give clarity: I have great respect for old and new Mainframes, COBOL and other software. I have great respect for the folks that work on these systems today.
My nerd/geek tweet was about my amazement of getting Pi to do this.
The Pi does not replace them.
The limits of twitter and my style created some ill feelings with some folks on this tweet. I can see how my series of sentences in the tweet could be taken without knowing my prior love of this stuff.
No—an entire bank can not run just on a Pi—but the test worked.