Service Assist Processor

SAP (Service Assist Processor) is a special type of processor , in IBM - mainframe computer is installed.

In the current models of the z / Series, a book contains two SAPs.

Its task is to control the input and output functions on a mainframe computer. For this purpose, the required input / output process is triggered asynchronously by a main processor. While the SAP takes care of the execution of the corresponding input / output command, the main processor can take care of the execution of further processes.

When the input / output command has been executed, an interrupt is triggered by the SAP. The main processor can then request the status of the input / output operation from the SAP and react accordingly.