TPL: A Data Layout Method for Reducing Rotational Latency of Modern Hard Disk Drive

This paper proposes a data layout method for reducing the rotation delay of read access in modern hard disk drive. TPL (track partition layout) is a data layout that mainly bases on the detailed knowledge of the hard disk´s physicalgeometry. By dividing one disk track into a set of partitions of sectors and duplicating data in these partitions, the rotational latency would be greatly reduced. And the method also contribute to minimizing the response time of disk request. We have implemented this layout method in the widely used disk simulator - DiskSim by slightly revising the code in disk controller module, and have chosen four different types of disk to run the experiment. As the simulation shows, with a typical workload trace, the average rotational latency decreased to 70% when dividing a track into only two partitions. This number further drops to 42% when the number of partition reaches 32. Also, the average overall I/O system response time drops correspondingly from 83% to 65%.