For this exam, you may not consult with people other than Jeff Ondich. Otherwise, you may use any sources of information, including books and the Internet.

Have fun.

1. (10 points) Do problem 6.9 on page 530 of Patterson and Hennessy.
   
   
2. (10 points) Consider the following caches, each of which can hold up to 16 32-bit words of data. Assume that addresses are 32 bits long.
   • A 16-entry direct-mapped cache with 1-word blocks.
   • A 4-entry direct-mapped cache with 4-word blocks.
   • A 4-entry 4-way set associative cache with 1-word blocks, using a "least recently used" strategy for choosing which block to evict.

   For each of these caches, answer the following questions.

   • Draw a diagram of the cache. How much memory does it use?
   • If the contents of the following addresses are requested in the indicated order, what words are in which entries at the end, and what is the hit ratio? Assume the cache starts out empty.

     	52, 13, 79, 57, 86, 12, 84, 14, 21,
     		102, 36, 25, 33, 26, 34, 98, 76, 38
     

     Note that these addresses are byte addresses--so byte 3 is contained in the word starting at address 0. Also, indicate a word by writing out its byte range (so the word starting at address 52, for example, would be written as "52-55").

   
   
   
3. (10 points) Read "On Holy Wars and a Plea for Peace" by Danny Cohen (IEEE Computer, v14, pp 48-54, October 1981). While you're at it, read in Patterson and Hennessy about byte order (also known as the big-endian/little-endian problem). Answer the following questions:
   • On all modern computer of which I am aware, the smallest addressable unit is the byte. Once a file is stored on such a computer system, bit order is irrelevant, since only bytes, half-words, and words are moved from hard drive to memory and back.

     Suppose you have a file consisting of a sequence of 32-bit integers, that the first integer in the file is 250, and that the file is stored on a system whose byte order is little-endian. Now transfer this file byte-for-byte to a big-endian byte order system. What is the first integer in the resulting file?

   • Use the UNIX command "od" to provide practical evidence about the byte order used on the Intel/Linux machines in CMC306 and 307. Do these systems use big-endian or little-endian byte order?
   
   
   
4. (3 points) Those jokes were awful. Let's try this instead: please recommend a book for me to read.
   
   
5. (20 points) When Fred Brooks taught class, he spoke very highly of John von Neumann's "First Draft of a Report on the EDVAC." I have given you a copy of the first ten pages of von Neumann's report. Read it and answer the following questions.
   • Throughout the report, von Neumann refers to the main subdivisions of a computing system as CA, CC, I, O, R, and M. To what modern concepts do these six subdivisions refer?

   • Section 1.2 refers to several mechanisms by which program instructions may be stored. Name a mechanism used in modern computing systems that is not contained in von Neumann's list.

   • Explain briefly in modern terms what 1.3 is about.

   • Explain briefly the meaning of the sentence starting "As to (h) (sorting and statistics), the situation is somewhat ambiguous..." in section 2.9.

   • Summarize von Neumann's arguments in favor of binary rather than decimal computation. Are these arguments still valid?

   • What the heck is going on in 5.4?

   • List three ideas in this paper that you find to be still valid and of greatest importance. Explain briefly why you chose these three.

   • List three ideas in this paper that you find to be obsolete. Explain briefly why you chose these three.
   
   
   
6. (1 point) Have a great break.