# Week 09 Notes for CST8281 - Fall 2011

Fall 2011 - September to December 2011 - Updated 2011-11-16 04:34 EST

# 1 Midterm Test #2 - 20%Index

• The Second Midterm Test date is posted on the Course Home Page.
• In class on Wednesday, November 9. Short answer and multiple choice.
• For full mark credit, read the Test Instructions for important directions on how to enter your answers on the mark-sense forms.
• The Second Midterm covers material on Assignments 01 through 07 inclusive and Week Notes 01 through 09 inclusive.
• Basic calculators are permitted for this test and the final exam. (No phones or PDA devices.) You will not need one if you know your powers of two. You will benefit from knowing the powers of two from 2^(-4) to 2^16 and the decimal and binary values of the hexadecimal digits from zero to fifteen. Of course you can work them out; however, having at least some of them memorized will make things go faster for you on the test. (Remember that hexadecimal “A” = decimal 10 = binary 1010.)

# 2 Final Exam Schedule PostedIndex

• The Final Exam date is posted on the Course Home Page.
• For full mark credit, read the Test Instructions for important directions on how to enter your answers on the mark-sense forms.
• Basic calculators are permitted for the final exam. (No phones or PDA devices.) You will not need one if you know your powers of two.

# 3 Lecture Notes for This WeekIndex

## 3.2 From Blackboard Course DocumentsIndex

These documents have restricted distribution and cannot be put on the Course Home Page.

• 06.ppt - Memory
• see memory speeds on slide 7
• see memory types, memory hierarchy (speeds), cache, virtual memory
• ignore slides 12-34, 37
• ignore anything on “segmentation” - focus on “paging” only

## 3.3 From the InternetIndex

About The Internet and its protocols:

Social Commentary:

About creating good HTML web pages:

## 3.4 From the Classroom Whiteboard/ChalkboardIndex

• Your in-class notes go here.

• Be aware of line-end differences in text files on Unix/Windows/Mac.

• Binary Humour: http://xkcd.com/953/

### 3.4.1 Memory, Cache, and Virtual MemoryIndex

• cache (from 06.ppt)
• what is the purpose of cache memory?
• how does the size of cache memory affect your programs?
• virtual memory (from 06.ppt)
• allows CPU to execute programs larger than physical memory
• one more level of indirection between the program and the memory
• program (virtual, logical) address - what the program uses
• memory (physical, real) address - what gets to the memory
• program has virtual pages (or just “pages”)
• memory has physical page frames (or just “frames”)
• page table, valid bit, page faults
• working set, thrashing
• Review of Cache and Virtual Memory
• cache hit, miss
• three types of locality
• basic feature VM allows
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