Disk I/O speed (latency and bandwidth) has and is expected to increase at a much slower rate than CPU speed and memory density. The gap in performance between the two continues to widen despite research and advancements in disk technology. I/O is emerging as a problem for all computer systems and application environments.
To compensate for the gap, we must fully understand the interaction between CPU, memory, and disk system, and make architectural and system enhancements accordingly. In order to do this, we have developed a set of tools (called TIME) that are designed to evaluate this interaction and to determine the role of new technologies in the storage system.
TIME is being used to investigate many issues involving I/O and its relationship to the memory system. The tools include a TLB simulator, virtual to real address translation via page tables, main memory allocation, I/O caches, and a disk system simulator.
The TIME tools mentioned are complete and are now being used to investigate I/O behavior. TIME is trace driven and designed to study real workloads rather than model statistical behavior. We have produced I/O traces from several workstation environments, using a modified operating system.