Date: Mon, 22 Jan 2007 12:25:30 -0600 (CST) From: Mark Jacobson To: 810-021-01-spring@uni.edu Subject: Read TechTalk pages 100-103 of textbook... Hi 021 students, On Wednesday, if nothing is working in the classroom to show the computer screens or the elmo (overhead projector), I will use the portable computer projector so I can show the textbook from the BookOnCD. However, the problems with our classroom projection equipment have been reported, so I expect they will have it fixed later today or for sure by Wednesday morning. Since the classroom projection system was unavailable today, we had to cover (on the whiteboard): The Machine Cycle - The I-Cycle and the E-Cycle The Machine Cycle consists of 6 numbered steps and is at the bottom of your handout from day number one that has: Fig 3-1. The hardware components of a computer system. Central Main Auxilary Input Output Processing Memory Memory Device Device Unit Mp Ms | | | | | V V V V V ---------------------------------------------------------- Bus ---------------------------------------------------------- at the top of the page, and The Machine Cycle with 2 numbered steps for the I-Cycle and 4 numbered steps for the E-Cycle at the bottom of the page. Study pages 100 to 103 of the textbook which is entitled: Tech Talk How a Microprocessor Executes Instructions I will show a Flash animation that is related to this fetch and execute cycle textbook material on Wednesday in class. The I-Cycle is the fetch part of the fetch/execute cycle. The E-Cycle is the execute part of the fetch/execute cycle. The Machine Cycle is just another name for the fetch/execute cycle. All computer CPU's operate by the fundamental fetch/execute cycle. After the fetch, but before the execute cycle is when the "Increment pointer to the next instruction" phase occurs. Page 101 Figure 2.51 shows a diagram of the instruction cycle. "4. Increment pointer to the next instruction" is in the WRONG place! It has to be BEFORE "3. Execute instruction" ------ It cannot be AFTER step #3, after "3. Execute instruction" No computer works that way! The Flash animation you will see on Wednesday will make this very clear. ---------------------------------------------------------------------------- The other part of class, we reviewed binary and base two to base ten conversion, and vice versa. Here are the four practice questions: What does 49 look like as a binary number? What does 99 look like as a binary number? What is the base ten (decimal) value of binary 01000001? What is the base ten or decimal value of base two 01010101? ---------------------------------------------------------------------------- Mark