09/01/1994 09:00 AM
Computer Engineering
In this dissertation, we investigate the performance evaulation of systems with restricted overlap of resources. The impetus of this study is derived from the constrained parallelism in the service of I/O requests in the current generation of cached disk controllers. Among other features, these cached contgrollers offer improved performance through an increase in the degree of transfer concurrency. In particular, we consider controllers that have the ability to service the next request for a given logical device, if it can be satisfied by the cache, in parallel with \"hidden\" disk activity, such as staging. We present a queueing model to represent the restricted overlap problem. The model is developed under exponential assumptions and then expanded to account for variability in service. We investigate the efficiency of three solution techniques. The model is also expanded to represent a shared logical device.
