Consider a disk that rotates at 3600 rpm. The seek time to move the head between adjacent tracks is 2 ms. There are 32 sectors per track, which are stored in linear order from sector 0 through sector 31. The head sees the sectors in ascending order. Assume the read/write head is positioned at the start of sector 1 on track 8. There is a main memory buffer large enough to hold an entire track. Data is transferred between disk locations by reading from the source track into the main memory buffer and then writing the data from the buffer to the target track. a. How long will it take to transfer sector 1 on track 8 to sector 1 on track 9

It will take 19.19 ms to transfer sector 1 on track 8 to sector 1 on track 9

The given parameters are:

--- the disk rotation

--- the sectors in a track

Calculate the time (t) to complete one revolution

So, the time to read/write to a sector is:

This gives

Convert to ms

Next, calculate the rotation time to head up sector 1 on track 8 to sector 1 on track 9

This is calculated as:

So, we have:

Convert to ms

So, the required time to transfer sectors is:

Time = 2 * Time to read/write to a sector + Seek time + Rotation time

This gives

Hence, it will take 19.19 ms to transfer sector 1 on track 8 to sector 1 on track 9

Read more about disk rotation at:

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19.71 ms

Explanation:

The disk rotates at 3600 rpm, hence the time for one revolution = 60 / 3600 rpm = 16.67 ms.

Hence time to read or write on a sector = time for one revolution / number of sectors per track = 16.67 ms / 32 sectors = 0.52 ms

Head movement time from track 8 to track  9 = seek time = 2 ms

rotation time to head up sector 1 on track 8 to sector 1 on track 9 = 16.67 * 31/32 = 16.15 ms

The total time = sector read time +head movement time + rotational delay + sector write time = 0.52 ms + 2 ms + 16.15 ms + 0.52 ms = 19.19 ms