Homework 7
Due 10/12/2011 3:59PM
Problem 1
The MegaGiga hard disk rotates at 5400 rpm with an arm seek time given
by = 4 + 0.05t msec, where t is the number of tracks the
arm seeks. Assume a block size of 512 bytes, and 1024 tracks with 512
sector/track.
The disk controller and DMA read or write data from/to disk at a rate of
4MB/sec.
-
What is the storage capacity of the disk?
-
Assume that we are reading a 16K-bytes file where the sectors happen to
be allocated contiguously on the same track. Compute the maximum and minimum
disk throughput that is possible while reading the file?
Problem 2
Suppose I have a disk such as the 320GB SATA drive described here
and I
have a workload consisting of 10000 reads to sectors randomly
scattered across the disk. How long will these 10000 request take (total)
assuming the disk services requests in FIFO order?
Problem 3
Suppose I have a disk such as the 320GB SATA drive described here and I have a workload consisting of
10000 reads to 10000 sequential sectors on the outer-most tracks of
the disk. How long will these 10000 request take (total) assuming
the disk services requests in FIFO order?
Problem 4
Suppose I have a disk such as the 320GB SATA drive described here and I have a workload consisting of
10000 reads to sectors randomly scattered across the disk. How long
will these 10000 request take (total) assuming the disk services
requests using the SCAN/Elevator algorithm.
Problem 5
Suppose I have a disk such as the 320GB SATA drive described here and I have a workload consisting of
10000 reads to sectors randomly scattered across a 100MB file, where
the 100MB file is laid out sequentially on the disk. How long will
these 10000 request take (total) assuming the disk services requests
using the SCAN/Elevator algorithm?