Estimate the average time to read a random sector from disk

Question

Consider a disk with a rotational rate of 10,000 RPM, an average seek time of 8 ms, and on average of 500 sectors per track. Estimate the average time to read a random sector from disk.

(A) 7.012 ms
(B) 11.012 ms
(C) 14.012 ms
(D) 10.012 ms

Comments

b)  11.012 ans ??

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yess

Answer 1

(seek tme+RL +Transfer time)

Rrotaion time : 10,000 r----------------------------- 60 sec
         so 1 rotation-----------------------60/10000 sec=6 msec
                                                           
RL will be=rotaion time /2

= 60/20000 sec

they want ans in msec so 60/20 msec=3 msec
  for transfer time : in i rotation it can read whole track and here track consists of 500 sector means
in 500 sector------------------------------6 msec
in 1 sec----------------------------------------6/500      

                                                               =0.012 msec
11.012 ans