An analysis of central processor-input-output processor contention
William D. Strecker · ACM SIGSIM Simulation Digest · 1979
Most computer systems have separate central (CPU) and input-output (IOP) processors to permit simultaneous computation and input-output (I/O). It is conventional in such systems to avoid any loss of I/O data by granting the IOP priority over the CPU for memory service. Although this priority discipline is simple to implement it may result in a maximum degradation of CPU performance. In this discussion an analysis of the IOP priority discipline is given together with an analysis of other priority disciplines which require the buffering of IOP requests and results are given showing that only a small amount of buffering is required to produce a noticeable improvement in CPU performance.