Big iron. Sounds indestructible, right? Reliability is indeed an advantage of mainframes, and it’s one of the primary reasons they have anchored the IT systems of Global 500 enterprises for more than 50 years. In fact, despite claims that mainframes are going the same route as the dinosaurs, they’re still in use by 70% of Global 500 companies with a mean time between failures (MTBF) that’s commonly measured in years. The problem is that these systems, relied upon to meet vital bulk data and transaction processing needs, are facing a greater cybersecurity risk than we truly realize.