RBOS

You probably don’t know the Red Baron Operating System, “R-Boss” (RBOS). It was named for a strip bar in Houston Texas and it carried billions, probably trillions, of dollars of credit card authorizations for American Express – including long after they lost the source code for it.

My first programming job was for the American Express Space Bank at the end of the 1960s. “Space Bank” was a relatively short-lived hotel and motel reservation system run by the credit card people.