Computer Science 322 Operating Systems Mount Holyoke College Spring 2008

Agenda

• Announcements
  • Finish up those lab demos!
  • Progress reports due Monday
• Project presentation scheduling
• Lecture assignment recap
• Memory Management
  • Working set simulator (the cancelled Lab 6)
  • The other major approach: Segmentation
    • like paging, but with variable-sized segments instead of fixed-size frames
    • allocate segments according to logical breakdown of memory usage
    • segment table requires base and offset
    • external fragmentation can be a problem (as with the contiguous allocation approach)
  • Combinations of Segmentation and Paging
    • Intel Pentium memory hardware
      • Lots of details in IA-32 Intel Architecture Software Developer's Manual, Volume 3: System Programming Guide, available in shared area. Don't print it - it's over 800 pages. Memory management is described in great detail in Chapter 3.
      • Better: excerpt from newest Tanenbaum OS text (see handout).
    • FreeBSD approach

Lecture Assignment

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

Turn in short answers to these questions. Please turn in a hard copy (typeset or handwritten are OK). We will discuss these questions during class, so no late submissions are accepted.

SG&G 8.10, 9.14, 9.15