MCS-170 The Nature of Computer Science

Fall 2006

Lecture 14

1. Review: Von Neumann Architecture (Chapter 14)

von neumann

The Von Neumann architecture. Directed lines represent
buses and the flow of information between the computer components.

2. CPU - The "Brains" of a Computer

(overhead - Reed, Fig. 14.1)
Each instruction takes one CPU cycle. But, not all computers share the same set of basic instructions. For example, Computer A might take two cycles to fetch a  piece of data from memory, whereas Computer B might take  four cycles.

So, 800 MHz CPU is not necessarily slower than a 1.0 GHz (=1000 MHz) computer. It depends on the basic instruction sets for the two computers and how many cycles instructions take. 

3. Datapath and Memory

Overhead - Fig. 14.6 from Reed
When we finish with the number at memory location 11, we have the sum stored in R0.