Consider an imaginary disk with 60 cylinders, numbered from 0. A request comes in to read a block on cylinder 15. While the seek to cylinder 15 is in progress, new requests come in for cylinders: 5, 20, 45, 10, 55 and 25 in that order. a) Starting from the current head position, with the disk arm initially moving to the larger number cylinders, use the tables on the sheet labelled Q1 in the provided Excel template to calculate the total head movements to satisfy all the pending requests for each of the SIX disk scheduling algorithms below.

i. FCFS ii. SSTF iii. SCAN iv. C-SCAN v. LOOK vi. C-LOOK Page |

3 b) Calculate the total seek time (TST) for the most efficient scheduling algorithm at a seek rate of 2msec per cycle