Question

Consider a disk with an average seek time of 4 ms, rotational delay of 2 ms. rotation of 15000 r.p.m. and 512-byte sectors with 500 sectors per track. A file occupies all of the sectors on 5 adjacent tracks. after reading the first track, if remaining tracks can be read with seek time, then the time required in sequential organization to transfer the file will be nearly

• A. 0.034 second
• B. 3.4 seconds
• C. 0.01 second
• D. 0.34 second

Answer 1

The correct option is A 0.034 second

option (b)

In one rotation 1 track can be transferred.

$\text{1 rotation time}=\frac{60sec}{15000}=\frac{{60}^{\ast }1000msec}{15000}=4msec.$

5 track transfer time = 4 * 5= 20 msec
5 track rotational delay = 2 * 5 = 10 msec
seek time used once as given = 4 msec

Total time = 20 + 10 + 4 = 34 msec = 0.034 sec