COMPARISON OF DISK SCHEDULING ALGORITHMS

Name      Description                  Remarks     (Selection according to requestor)

RSS        Random scheduling     for analysis and simulation

FIFO      First in first out            Fairest of them all

PRI         Priority by process     Control outside of disk queue   management

LIFO      Last in first out            Maximize locality and resource utilization

            (Selection according to requested item)

SSTF                 Shortest seek time first             High utilization, small queues

SCAN                Back and forth over disk            Better service distribution

C-SCAN            One way with fast return           Lower service variability

N-step-SCAN    Multiple queues                          Scan N records at a time        

                                                                           Service guarantee

FSCAN              SCAN using 2 queues                 load sensitive