Question

A Java application needs to load 50 libraries. To load each library, one disk access is required. Seek time to access the location is 10 ms. Rotational speed is 6000 rpm. The total time needed to load all libraries is
1. 0.65 sec
2. 0.75 sec
3. 0.85 sec
4. 1 sec

Answer 1

Correct Answer - Option 2 : 0.75 sec

The correct answer is 0.75 sec.

Average seek time for a random location time is given as 10 ms. The average rotational latency is half of the time needed for complete rotation. It is given that 6000 rotations need 1 minute. So one rotation will take 60/6000 seconds which is 10 ms. Therefore average rotational latency is half of 10 ms, which is 5ms.

Average disk access time = seek time + rotational latency

= 10 ms + 5 ms = 15 ms

For 50 libraries, the average disk access time will be 15*50 ms =750ms

1 sec = 1000 ms

750 divide the time value by 1000 =0.75

Therefore option 2 is correct