Homework $7$

$($Help with Correct Answers Please!$)$

Type your answers in this Word document. Write your name in the header. Rename the file to

YourLastname hw$7.$docr and submit to the correct assignment in BLaze VIEW.

Show your solution steps to receive partial credit

Suppose the daytime processing load consists of $60\%$ CPU activity and $40\%$ disk activity.

Your customers are complaining that the system is slow. After doing some research you

have learned that you can upgrade your disks for $$8,000$ to make them $2\mathrm{.}5$ times as fast as

they are currently. You have also learned that you can upgrade your CPU to make it $1\mathrm{.}5$

times as fast as the current CPU for $$5,000.$

a$.$ Which upgrade option would give a faster system?

b$.$ Which upgrade option would give the best return of investment for each percent

of speed improvement?

Show your calculation to support your conclusion.

Suppose a disk drive has the following characteristics:

$6$ surfaces

$1024$ tracks per surface

$256$ sectors per track

$512$ bytes$/$sector

Track$-$to$-$track seek time of $8$ milliseconds

Rotational speed of $5000$ RPM$.$

a$.$ What is the total capacity of the drive?

b$.$ What is its average access time?