CS439: Principles of Computer Systems

Discussion Section 5 Problem Set

Due in Section on Friday, October 10, 2025

The problem set must be completed before section and brought to section. To ensure that your problem set is turned in correctly and that you receive credit for discussion section, you must follow these guidelines exactly.

Include the following header at the top of your file:

Discussion Section Problem Set #:
Student Name:
EID:

You may either type your answers or write them by hand, but you must have a copy with you in discussion section.

In discussion section, your TA will check that you made a good effort on the problem set, you are participating in the discussions in section, and you are ready and able to answer when called upon. If all of those are true, you will receive credit for discussion section that day. Note that a "good effort" on the problem set includes that all answers are in words unique to you and not copied from anywhere else, including the slide deck.

What is a virtual address? What is a physical address? How do they relate to each other?
What are overlays? How and why were they created?
Assume you have a virtual memory system that uses paging. Is the system vulnerable to internal and/or external fragmentation? Explain.
In class, we discussed that paging may increase internal fragmentation. What is internal fragmentation? What steps could you take to reduce it?
Consider a paging system with 256 pages and 65536 bytes of physical memory. The page size of the system is 512 bytes.
1. How many bits represent the page number?
2. How many bits are in the complete virtual address?
3. How many bits are in a physical address?
4. What size are the page frames?
5. How many physical frames exist?