Can anyone help me out with this excercise? Consider a single-platter disk with

Question

Can anyone help me out with this excercise?

Consider a single-platter disk with the following parameters: rotation speed: 5400 rpm; number of tracks on one side of platter: 10,000; number of sectors per track: 600; seek time: one ms for every hundred tracks traversed. Let the disk receive a request to access a random sector on a random track and assume the disk head starts at track 0.

a. What is the average seek time?

b. What is the average rotational latency?

c. What is the transfer time for a sector?

Explanation / Answer

SOLUTION:-

(a) On assumption that the disk head starts at track 0, then the computation will be easier to understand.

Request track = track 0, so seek time = 0

If Requested track = track 9999, so the seek time will be that time which will traverse 9999 tracks. As per random request, number of tracks traversed on average will be = (9999 / 2 ) = 4999.5 tracks. on one ms for every hundred tracks traversed, the average seek time   = ( 4999.5 / 100 ) = 49.995 ms

(b) rotation speed: 5400 rpm, ( ( ( 1 / 5400) * 60 ) * 106 ) / 103 = 11.111

So there will be one rotation every 11.111 ms

the average rotational latency = ( 11.111 / 2 ) = 5.555 ms

(c) number of sectors per track: 600 and one total rotation every 11.111 ms. So the transfer time for a sector = ( 11.111 ms / 600 ) = 0.01852 ms

===========================================================================

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.