recovered from an IBM Internal Use Only laserdisc, IBM Library number ZZ25-6897.

Many people have heard the term mainframe, but have no real idea what one was. The 3090, was one of the last actually mainframe based systems. Today's zSeries mainframes are actually a computer in the same way a PC is a computer. While the Input/Output devices are not inside the zSeries processor, everything else is.

Here on the 3090, many of the components of what makes are modern computer are outside, in their own "frames". This video will help you understand the major components of the IBM 3090 Processor.

When people used to complain about the price of mainframes, in the same way, most people didn't have a clue about the level of complexity and engineering that went into the design of these systems. There is almost nothing like this anymore.