Computer Science 432/563
Operating Systems

Spring 2016, The College of Saint Rose

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Agenda

• Announcements
  • Lab 4: Unix Systems Programming due tomorrow night
  • Programming Project 3: knish: The Knight Shell first deadline in just under a week
  • Term Project first deadline is group formation late next week
  • Accepting Programming Project 2: CPU Scheduler Simulation "do overs" on simulation case studies through the weekend
• Midterm exam due back now
• Memory Management
  • Binding time
    • Programming or compile time
    • Load time
    • Execution time
  • Logical vs. Physical Address Space
  • Memory protection
  • Swapping
  • Contiguous allocation
    • hardware support: limit and base/relocation registers
    • first-fit/best-fit/worst-fit
  • Fragmentation
    • external: waste between allocated chunks
    • internal: waste within allocated chunks
    • reduce external fragmentation with a compaction operation

Lecture 0x0e Assignment

Due at the start of class, Monday, March 21.

Please submit answers to these questions either as a hard copy (typeset or handwritten are OK) or by email to terescoj AT strose.edu by the start of class. Please use a clear subject line when submitting by email (e.g., CS 432 Lecture 0x0e Assignment, Mary Smith). We will discuss these questions at the start of class, so no late submissions are accepted.

The readings for next class are SG&G Chapter 7.

• SG&G Exercise 5.38, p. 256 (6 points)
• SG&G Exercise 5.39, p. 256-7 (4 points)
• Consider this resource allocation state for four different non-preemptible resource types R0, R1, R2, and R3. Assume maximum claims and current resource assignments for five processes P0, P1, P2, P3, and P4, are given in the following table, along with the total number of each resource available (not including allocated resources).

  	Max Claims					Current Use
  Resource	P0	P1	P2	P3	P4	P0	P1	P2	P3	P4	Avail
  R0	0	1	2	0	0	0	1	1	0	0	1
  R1	0	7	3	6	6	0	0	3	6	0	5
  R2	1	5	5	5	5	1	0	5	3	1	2
  R3	2	0	6	2	6	2	0	4	2	4	0

  Is this state safe? (4 points)

• If a request arrives from process P1 for 4 instances of R1 and 2 instances of R2, can the request be granted immediately? (4 points)