What amazes me is the software running the banking accounts. Whenever I go to an ATM machine, and I get the receipt, I never for a moment think they can be wron

What amazes me is the software running the banking accounts. Whenever I go to an ATM machine, and I get the receipt, I never for a moment think they can be wrong by even one cent. Because they've never been wrong. From time to time you hear of a case where someone found a million dollars in their account, but this gets to be reported in newspaper. And to be honest I don't even remember how many years ago I read such a story. I imagine there are tens of millions of people accessing their bank accounts every single day. A bank like Chase or Bank or America, or Wells Fargo probably processes millions of transactions per second. With essentially zero errors. Meaning 99.99999999% correctness, with too many nines to count. How is that possible? Not to mention, these guy are probably under hundreds of hacker attacks per day.