CS439: Principles of Computer Systems

Discussion Section 6 Problem Set

Due in Section on Friday, March 8, 2024

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:
What goes in a bowl of cereal first?:

Partner Name:
EID:
What goes in a bowl of cereal first?:

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 worked with your partner, 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 your partner and not copied from anywhere else, including the slide deck.

What causes a page fault? What is the end result for the running process?
What is TLB (Translation Lookaside Buffer)? What issue does it try to solve? How does it solve that issue?
In a 32-bit machine we subdivide the virtual address into 4 segments as follows:

10-bit 8-bit 6-bit 8 bit

We use a 3-level page table, such that the first 10-bits are for the first level and so on.
1. What is the page size in such a system?
2. What is the size of a page table for a process that has 256K of memory starting at address 0?
Consider a program with seven virtual pages numbered from 0 to 6 references its pages in the order:

0 1 3 6 2 4 5 2 5 0 3 1 2 5 4 1 0

Using clock page replacement algorithm with 4 frames and assuming demand paging, compute the number of page faults and show the state of frames (pages in frames and value of clock bit) after each page access.
What is the difference between global and local page replacement policies? Name a disadvantage of each.
Name two advantages of using small pages and two advantages of using large pages in a paging mechanism. Why are page sizes growing in paging memory systems?