# computer architecture FEB 10

Question 1(10 Points)

What are the advantages of using a glass substrate for a magnetic disk?

Question 2 (10 Points)

Explain serpentine recording.

3.Explain the difference between a simple CAV system and a multiple zone recording system.

4.What differences between a CD and a DVD account for the larger capacity of the

DVD?

5.Consider a single-platter disk with the following parameters:

• Rotation speed: 7200 rpm;
• Number of tracks on one side of platter: 30,000
• Number of sectors per track: 600;
• Seek time: one ms for every hundred tracks traversed.
• Assumption: Let the disk receive a request to access a random sector on a random track and assume the disk head starts at track 0.

What is the average seek time?

6.Consider a single-platter disk with the following parameters:

• Rotation speed: 7200 rpm;
• Number of tracks on one side of platter: 30,000
• Number of sectors per track: 600;
• Seek time: one ms for every hundred tracks traversed.
• Assumption: Let the disk receive a request to access a random sector on a random track and assume the disk head starts at track 0.

What is the average rotational latency?

7.Consider a single-platter disk with the following parameters:

• Rotation speed: 7200 rpm;
• Number of tracks on one side of platter: 30,000
• Number of sectors per track: 600;
• Seek time: one ms for every hundred tracks traversed.
• Assumption: Let the disk receive a request to access a random sector on a random track and assume the disk head starts at track 0.

What is the transfer time for a sector?

8.Consider a single-platter disk with the following parameters:

• Rotation speed: 7200 rpm;
• Number of tracks on one side of platter: 30,000
• Number of sectors per track: 600;
• Seek time: one ms for every hundred tracks traversed.
• Assumption: Let the disk receive a request to access a random sector on a random track and assume the disk head starts at track 0.

What is the total average time to satisfy a request?

9.Consider a magnetic disk drive with 8 surfaces, 512 tracks per surface, and 64 sectors per track.

• Sector size = 1 kB.
• Average seek time = 8 ms,
• Track-to-track access time = 1.5 ms,
• Drive rotates at 3600 rpm.
• Successive tracks in a cylinder can be read without head movement.

What is the disk capacity?

10.Consider a magnetic disk drive with 8 surfaces, 512 tracks per surface, and 64 sectors per track.

• Sector size = 1 kB.
• Average seek time = 8 ms,
• Track-to-track access time = 1.5 ms,
• Drive rotates at 3600 rpm.
• Successive tracks in a cylinder can be read without head movement.
• What is the average access time?

11. Consider a magnetic disk drive with 8 surfaces, 512 tracks per surface, and 64 sectors per track.

• Sector size = 1 kB.
• Average seek time = 8 ms,
• Track-to-track access time = 1.5 ms,
• Drive rotates at 3600 rpm.
• Successive tracks in a cylinder can be read without head movement.

Assume this file is stored in successive sectors & tracks of successive cylinders, starting at sector 0, track 0, of cylinder i

Estimate the time required to transfer a 5-MB file.