What Is a zIIP Specialty Engine?

Though physically identical to a central processor, the zIIP engine is microcoded at installation time to run specific types of workloads. The central processor continues to handle the operating system, I/O interrupts and timer interrupts, job initiations, and user interactions with the operating system. The zIIP concentrates on CPU intensive workloads, leaving the central processor more time to absorb otherwise queued workloads, thereby achieving some overall performance improvement across all mainframe activity.