CSI 3640 - Final Exam Review

Exam Contents:

A) Section 5.1 of the Textbook [Cache Memory]

B) PDF file on Storage and Other IO (Sections 6.2, 6.3, 6.4, and 6.9)

C) PDF file on Binary and Decimal Conversion

D) Section 3.5 (only pages 205-215) of the textbook [Floating Point Numbers]

E) Section 2.12 of the textbook [Compiler, Assembler, Linker, and Loader]

F) PDF file on Wallace Tree Multiplier

G) PDF file on Multiprocessors

H) PDF file on Digital Logic (pages 396-405)[Sequential Circuits]

A) Section 5.1 of the Textbook [Cache Memory]

From the earliest days of computing, programmers have wanted _________.

From the earliest days of computing, programmers have wanted unlimited amounts of fast memory.

The topics in this chapter aid programmers by creating that illusion.

Consider the analogy below and explain how it demonstrates the illusion of a large memory that we can access as fast as a very small memory.

Suppose you were a student writing a term paper on important historical developments in computer hardware. You are sitting at a desk in a library with a collection of books that you have pulled from the shelves and are examining. Having several books on the desk in front of you saves time compared to having only one book there and constantly having to go back to the shelves to return it and take out another.

The same principle allows us to create the illusion of a large memory that we can access as fast as a very small memory.

Just as you did not need to access all the books in the library at once with equal probability, a program does not access all of its code or data at once with equal probability. Otherwise, it would be impossible to make most memory accesses fast and still have large memory in computers, just as it would be impossible for you to fit all the library books on your desk and still find what you wanted quickly.

Principle of Locality:

1) What is it?

2) What are the two different types of locality?

1) Principle of Locality:

• The principle of locality underlies both the way in which you did your work in the library and the way that programs operate.

• The principle of locality states that programs access a relatively small portion of their address space at any instant of time, just as you accessed a very small portion of the library’s collection.

2) There are two different types of locality:

• Temporal Locality

• Spatial Locality

Temporal Locality:

1) What is it?

2) Give an example.

1) Temporal locality (locality in time): if an item/data location is referenced, it will tend to be referenced again soon.

2) Example: If you recently brought a book to your desk to look at, you will probably need to look at it again soon.

Spatial Locality:

1) What is it?

2) Give an example.

1) Spatial locality (locality in space): if an item/data location is referenced, items/data locations with nearby addresses will tend to be referenced soon.

2) For example, when you brought out the book on early English computers to learn about the EDSAC, you also noticed that there was another book shelved next to it about early mechanical computers, so you likewise brought back that book and, later on, found something useful in that book.

• Libraries put books on the same topic together on the same shelves to increase spatial locality.