A lot of mission critical systems are Java on the mainframe. Not just Cobol. Why don't people switch, then? The mainframe gives you a predictible runtime. Lon

A lot of mission critical systems are Java on the mainframe. Not just Cobol. Why don't people switch, then? The mainframe gives you a predictible runtime. Long running jobs don't get rescheduled or hogged by other loads. I know about a firm that uses a mainframe to control a factory line. The problem with replacing stuff that works (and the mainframe does) is then your job is on the line if the transition fails, and there are a lot of business moving parts inside.