| Teaching computer architecture is an interesting challenge for the instructor because the field is in constant flux. What the architect does depends strongly on the devices available, and the devices have been changing every two to three years, with major breakthroughs once or twice a decade. Within the brief life of the first edition of this textbook a whole generation of processor and memory chips were first offered for sale, appeared in popular computers, and then gradually disappeared from the marketplace as their successors took their places. The particular features and strengths of those devices have given way to other features in various new combinations and new relative costs. Design practices are evolving to exploit the new devices for a new generation of machines. And they will evolve again as the next wave of devices appears in the coming years.
What then should be taught to prepare students for what lies ahead? What information win remain important over the technical career of a student, and what information will soon become obsolete, of historical interest only? This text stresses design ideas embodied in many machines and the techniques for evaluating those ideas. The ideas and the evaluation techniques are the principles that will survive. The specific implementations of machines that one might choose in 1995 2000, or 2005 reflect the basic principles described here as applied to the device technology currently prevailing. Effective designs are those that use technology cleverly and achieve balanced, efficient structures matched well to the class of problems they attack. This text stresses the means to achieve balance and efficiency in the context of any device technology. |
