A study of I/O system organizations

Abstract

The author looks at several design options in designing an I/O system and studies their impact on the performance. Specifically, trace-driven simulations are used to study a disk system with a nonvolatile cache. Some of the design parameters considered include the cache block size, the fetch size, the cache size and the disk access policy. It is shown that decoupling The fetch size and the cache block size results in significant performance improvements. A write-back policy that is shown to offer significant performance benefits is introduced. It is shown that optimal block size in a two-level memory hierarchy is dependent only on the latency, data rate product of the second level as previously conjectured. Results showing the effect of a split-access operation of a disk read/write head are also presented.