This assignment 5:15 PM on 1 May. Since the Undergraduate Research Symposium is meeting on May Day, our class is canceled for that day, but you can still upload your solution in PDF format to Homework 9 by the due date.
Problem 1 from the textbook
Do problem 6.23 of page 649 of the textbook.
Problem 2 Expected access time — disk
Assume the following:
- 80% of the time a read request is found in the “buffer” and retrieved in 30 µsec.
- 20% of the time a read request must be retrieved from the disk which requires 10 msec.
What is the average time required to perform a read request?
Express your answer in µsecs.
Problem 3 Expected access time — cache
Assume the following:
- 98% of the time a read request is found in the cache and retrieved in 20 nsec.
- 2% of the time a read request must be retrieved RAM and requires 10 µsec.
What is the average time required to perform a read request?
Express your answer in nsecs.
Problem 4 Expected money — vending
Assume the following when you look in the coin return of the vending machine outside of RRO 215:
- 99.8% of the time, there is no money in the coin return.
- 0.1% of the time, there is 2¢ in the coin return.
- 0.1% of the time, there is 35¢ in the coin return.
What is the average return of searching the coin return slot?
Express your answer in m¢.