IBM's mainframes are the oldest line of computers, dating back to 1964 and occupy a special place as the world's first instruction set architecture. This longevity and extreme backwards compatibility are responsible for perhaps the most lucrative computer franchise. IBM's z196 is the first mainframe with an out-of-order CMOS microprocessor, and also the first with an integrated L3 cache. These two innovations are largely responsible for a 30-40% improvement in performance over the previous generation z10 servers.

While mainframes are only found in rarified server environments, the impact on modern computing is undeniable. They are found in many critical applications such ATMs, airline reservations, and hardly a day goes by when a consumer does not indirectly use a mainframe.



Link: Real World Tech