average time to read data

Question

Consider a disk system, which has a track seek time of t seek = 10ms (mini-second). The disk rotation speed is r = 9000 rpm (round per minute), and each track on the disk has S=600 sectors, each sector has total B=512 bytes data. What is the average time (in ms) it takes to read 1024 bytes data? (correct to three decimal places)

Comments

13.352 right??

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Yes . please provide solution

Answer 1

9000 rotation ------- 1min

1 rotation ---------- (60/9000) sec =6.66 msec

Average rotational time = 0.5*rotation time= 3.33 msec

1 rotation = 1 track = 600 sectors

hence time for 1 sector =(6.666/600)= 0.011 msec

we have to read 1024 B that is equal to two sectors .

total time = t(seek) + t(avg rotational) + t(transfer)

              = 10 ms +3.33 ms+ 2* 0.011 ms

              =13.352 ms