The 9373 and 9375 pipelined processing unit

The IBM 9370 processor family uses System/370 (S/370) architecture, which consists of three parts: the central processing unit (CPU), memory, and I/O control. This paper explains how the 9373 and 9375 CPU instruction processing cards fetch and execute S/370 instructions.To obtain the maximum performance, the CPU is designed as a pipelined processor. Pipelining is a method used in processor design to optimize performance of a sequential stream of instructions. In a sequential stream of instructions, the processor knows what the next instruction is before the current one is completed; consequently, it can begin execution of it. In some cases, the processor can start some phase of the execution of several instructions before executing the current one, thus giving depth to the pipe. The 9373 and 9375 CPU cards take full advantage of pipelining to deliver optimum performance.