1. CSCI 6307 Foundation of Systems – Exercise (3)
Xiang Lian
The University of Texas – Pan American
Edinburg, TX 78539

2. Direct-Mapped Cache
Assume that we have a list of 16-bit memory address references:
6, 214, 175, 214, 6
Given a direct-mapped cache with 16 one-word blocks (initially empty),
Please identify the binary address, the tag, and the index of the address references above
Please also list if each address reference is a hit or a miss

3. Direct-Mapped Cache (cont'd)
16-bit memory address references: 6, 214, 175, 214, 6
a direct-mapped cache with 16 one-word blocks (initially empty)
Address Reference
Binary
Tag
Index
Hit or Miss 6
214
175

4. Synchronization
What is the function of a semaphore? What are the operations that can be applied to a semaphore?
What is a condition variable? What are the operations that can be applied to a condition?

5. Write a Program
Suppose processes p0 and p1 can access the same bank account (shared variable balance). Process p0 add "amount" to the account balance, whereas process p1 withdraw "amount" from the bank account. Please write a code fragment for processes p0 and p1 using the semaphore.

6. Process Scheduling
Suppose that there are five processes in a system, their service time and arrival time are given below:
Draw the Gantt chart and compute average waiting time for the following methods. Here the waiting time of a process includes all the times it is in the ready list. Assume the context switching time is negligible.
1. First-Come-First-Served
2. Shortest-Job-Next (non-preemptive)
3. Shortest-Remaining-Job-Next (i.e., preemptive SJN)
4. Round-Robin with time quantum of 2
5. Round-Robin with time quantum of 4
Process
Arrival time
Service time P1 7 P2 20 P3 5 P4 10 P5 8 4