Question

What is the transfer time for a hard drive rotating at 7,200 rpm or 120 revolutions per second?assume there are 30 sectors per track. (give your answer in milliseconds)

Option 1:
2 milliseconds

Option 2:
4 milliseconds

Option 3:
6 milliseconds

Option 4:
8 milliseconds

Answer 1

The transfer time for a hard drive rotating at 7,200 rpm with 30 sectors per track is approximately 8 milliseconds. This calculation involves converting angular velocity to radians per second, determining the time for one revolution, and considering the number of sectors per track. Thus, Option 4: 8 milliseconds is accurate.

Step-by-step explanation:

To calculate the transfer time for a hard drive rotating at 7,200 rpm, we need to consider the number of sectors per track and the angular velocity. The angular velocity is given as 120 revolutions per second. To convert this to radians per second, we multiply by 2π (since there are 2π radians in one revolution). So, the angular velocity is 240π radians per second. Now, we can calculate the time it takes for one revolution by dividing 1 by the angular velocity: 1 / (240π) seconds. Since there are 30 sectors per track, the transfer time for one sector is (1 / (240π)) / 30 seconds. To convert this to milliseconds, we multiply by 1000: (1 / (240π)) / 30 × 1000 milliseconds. Simplifying this expression gives approximately 8 milliseconds as the transfer time for a hard drive rotating at 7,200 rpm with 30 sectors per track.