Scheduling I/O requests with deadlines: A performance evaluation

The I/O scheduling problem is examined in detail. The authors present a realistic model for studying this problem in the context of a system which executes real-time transactions. The model takes advantage of the fact that reading from the disk occurs before a transaction commits, while writing to the disk usually occurs after the transaction commits. New algorithms are presented that exploit this fact in order to meet the deadlines of individual requests. The algorithms are evaluated via detailed simulation and their performance is compared with traditional disk scheduling algorithms