Abstract: In order to investigate the behaviour of a data storage system, the time differences between commands from an analysis device and the completion of the operations defined by those commands are analyzed. The method may use a factorial parameter table definition representing common threads of I/O events in a patterned, cyclic nature, using a host computer as the host application emulator and data logger. The workload definition is provided either from hypothetical proposed thread parameters, or by statistical and common factorial analysis of real application I/O traffic analysis, or a combination of both. The generated workloads can be run while measuring the I/O event completion timings and event queuing characteristics, facilitating engineering interpretation of results for the purpose of analysing the effects of workload and system architectural design factors, and optimisation or evaluation of total system configurations.