A number of techniques have been developed for maximizing disk utilization in media servers, including disk arm scheduling and data placement ones. Instead, in this paper we focus on how to efficiently utilize the available memory. We present techniques for best memory use under different disk policies, and derive precise formulas for computing memory use. We show that with proper memory use, m...

Disk scheduling is one of the main responsibilities of Operating System. OS manages hard disk to provide best access time. All major Disk scheduling algorithms incorporate seek time as the only factor for disk scheduling. The second factor rotational delay is ignored by the existing algorithms. This research paper considers both factors, Seek Time and Rotational Delay to schedule the disk. Our ...

Declustered data organizations in disk arrays (RAIDs) achieve less-intrusive reconstruction of data after a disk failure. We present PDDL, a new data layout for declustered disk arrays. PDDL layouts exist for a large variety of disk array configurations with a distributed spare disk. PDDL declustered disk arrays have excellent run-time performance under light and heavy workloads. PDDL maximizes...

The performance of disk system is critical to the overall system performance. In order to maximize the performance of disk I/O, it is necessary to understand accurately the characteristics of the disk system. We propose a refined model of disk I/O operations based on the characteristics of present day disks and present experimental results supporting the model. To model a modern disk system, we...

Starting from disk access traces obtained during normal system use of 4.2BSD-based file systems, we established a repeatable simulation environment across a range of workloads and disk types for comparing different shuffling algorithms. We explored several of these, including how often to make layout changes, how large a unit of data to shuffle, and some mechanisms to exploit sequentiality of r...