1 votes 1 votes Suppose a disk has 100 cylinders, numbered from 0 to 99. At some time the disk arm is at cylinder 20, and there is a queue of disk access requests for cylinders 10, 22, 6, 38, 2, 40, 20. No of seeks in FCFS SSTF Operating System disk-scheduling operating-system + – jatin khachane 1 asked Dec 11, 2018 jatin khachane 1 1.1k views answer comment Share Follow See all 11 Comments See all 11 11 Comments reply sandygate commented Dec 13, 2018 reply Follow Share 1. 164 2. 60 0 votes 0 votes Devvrat Tyagi commented Dec 14, 2018 i edited by Lakshman Bhaiya Nov 1, 2019 reply Follow Share 144 56 0 votes 0 votes altamash commented Dec 15, 2018 reply Follow Share FCFS:164 SSTF;60 0 votes 0 votes Gopi Thawre commented Jan 31, 2019 i edited by Lakshman Bhaiya Nov 1, 2019 reply Follow Share FCFS : 164 SSTF : 60 0 votes 0 votes Lakshman Bhaiya commented Nov 1, 2019 i edited by Lakshman Bhaiya Nov 1, 2019 reply Follow Share @Satbir Is this correct? FCFS$:164$ SSTF$:60$ 0 votes 0 votes Satbir commented Nov 1, 2019 reply Follow Share No ...it should be 164 because at first the head moves from 20 to 10 and processes it and at last it again comes back to process 20. $20 -10 = 10$ $10-22 =12$ $22-6 = 16$ $6-38= 32$ $38-2 =36$ $2-40=38$ $40-20 = 20$ ____________ Total = $164$ SSTF is correct. 1 votes 1 votes Lakshman Bhaiya commented Nov 1, 2019 reply Follow Share Why head comes to $20$ again? 0 votes 0 votes Satbir commented Nov 1, 2019 reply Follow Share see the last request its 20 1 votes 1 votes Lakshman Bhaiya commented Nov 1, 2019 reply Follow Share Yes It is FCFS ,so head come to $20$,but other than FCFS,head is not come,because it start from $20$ Is this correct? 0 votes 0 votes Satbir commented Nov 1, 2019 reply Follow Share Yes, depends on the policy used. like in SSTF 20 is processed first. 1 votes 1 votes Lakshman Bhaiya commented Nov 1, 2019 reply Follow Share Yeah thanks 0 votes 0 votes Please log in or register to add a comment.