Suppose a disk drive has the following characteristics: 1. Four surfaces
2. 1,024 tracks per surface
3. 128 sectors per track
4. 512 bytes/sector
5. Track-to-track seek time of 5ms
6. Rotational speed of 5,000rpm 1.

Required:
a. What is the capacity of the drive?
b. What is the access time?

a. 256MB

b. 11 ms

Explanation:

a. The capacity of the drive is

As we know that

= 256MB

b. Now the access time is

As we know that

Average access time= seek time + average rotational latency

where,

seek time = 5ms

And, average rotational latency is

= 12 ms

So, average rotational latency is 6 ms

So, average access time is

= 5 ms + 6 ms

= 11 ms                    

We simply applied the above formulas

answer: 31, 5556. 952 seconds