Do you know that mainframe systems have several kinds of engines (i.e., processors) not just a Central Processor (CP)? Early mainframes had only one processor – the Central Processing Unit (CPU). As the mainframe industry evolved over the decades, today’s systems have a Central Processor Complex (CPC) consisting of several different processor types. Each processor type is used for a specific purpose. Technically, all processors are the same out of the box, but are configured as specific engine types during installation, or at any time later by IBM. Unlike CPs, which can be configured to run at lower speeds for software cost reasons, specialty processors usually run at full speed.