University of Helsinki Department of Computer Science
 

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Operating Systems, Fall 2006, Homework 6

This homework will be covered in practise session on Thursday 12.10.2006 (week 41).

The exercises are based on chapter 8.

  1. Memory Managent Policies
    • Problem 8.4 from course book [Stal05] (Problem 8.2. [Stal01]. Please notice that the problem has slightly changed: The second row in the R bit colums should be 1. The whole R bit column is 0 1 1 1.)

  2. Replacement algorithm
    1. Problem 8.5 from text book [Stal05, s. 384] (Probl. 8.3 [Stal01])
    2. What is special with this situation? What can you deduce from it?

  3. Working Set
    • Problem 8.15 a) from course book [Stal05]: (The problem is not available in the 4th edition.)
      Consider the following sequence of page references (each element in the sequence represents a page number):
      1 2 3 4 5 2 1 3 3 2 3 4 5 4 5 1 1 3 2 5
      Draw a diagram similar to that of Figure 8.19 for the reference sequence just defined for the values (delta)= 1,2,3,4,5,6.

  4. VSWS
    1. Problem 8.16 from text book [Stal05] (Probl. 8.13 [Stal01])
    2. What if Q was global, but dynamic. Give a similar mechanism for this case. Compare it to the mechanism given in (a). When would it be better? When worse?

  5. Linux.
    Linux memory management maps a conquous virtual memory area into a contiquous block of physical frames.
    1. What is the gain with this approach?
    2. What problems does it cause?
    Consider both general memory management policies as well as physical device usage.
FIRST COURSE EXAM is on Thursday 19.10. at 9.00-12 in the small auditorium CK112.
The exam covers
  1. exercises 1-6 and
  2. book chapters 1-8 (sections 5.1 - 6.6 are not included).
  3. Please notice that the second team task is part of this exam area, even if it's deadline is after the exam.
Please take id (student card, passport) with you to the exam. The Id needs to have your name and photo.
You also need to take pencils (or pens) with you to the exam. You may also take some snacks.
You are not allowed to have any notes, books or other written material available in the exam.


Tiina.Niklander@cs.helsinki.fi