Interestingly, the guys who hacked the bank mainframes[1] in Europe used Hercules and bootleg copies of z/os to find the exploits they used.<p>[1] <a href="https://www.pcworld.com/article/2034733/pirate-bay-cofounder-charged-with-hacking-ibm-mainframes-stealing-money.html" rel="nofollow">https://www.pcworld.com/article/2034733/pirate-bay-cofounder...</a>