Understanding the Microprocessor

I've been writing on CPU technology here at Ars for almost five years now, and during that time I've done my best to communicate computing concepts in as plain and accessible a manner as possible while still retaining some level of technical sophistication. Without exception, though, all of my CPU articles have been oriented towards the investigation of technologies currently on the market; I've written no general introduction to any of the concepts that I've used in these investigations, opting instead to integrate some introductory material into the more advanced discussions as space allows. As a result, I always get feedback from people who express regret that there were portions of my articles that they didn't understand due to their lack of background in the material. This is unfortunate, and for some time I've considered doing a more generalized introduction to the basic concepts in computing. Events have recently conspired to afford me that opportunity, hence the present article, which is the first in a series on the basics of microprocessor technology.There are a number of good reasons to do an article like this, now. One reason, as I've suggested above, is to provide readers with a better background for understanding my previous work. After reading this article you should be able to go back and revisit some older articles that you only half digested and get more out of them. But the main reason for doing a general introduction to microprocessor technology is forward-looking: that there are a number of new processors slated to come out in the next year and this article will help to lay the groundwork for my coverage of those designs. Itanium2, Yamhill, the PPC 970, AMD's Hammer, and even the Playstation3 are all on the horizon, and we at Ars want to be proactive about helping you get ready to understand what makes all of those technologies tick.Due to the continuing success of the Ars RAM Guide, I've chosen to model the present series on it. I'll start out at a very basic level with this first article, and as the series progresses I'll advance along the axes of chronology and complexity from older, more primitive technologies to newer, more advanced ones. The one important difference between this article and the RAM guide is in this article's relative lack of real-world examples. There are a number of reasons why I've chosen to forego detailed discussions of present-day implementations, but the primary one is that such discussions constitute.Judging by the steady stream of feedback I've gotten on it over the years, the following, which was part of my article on SIMD, has proven to be one of the most popular diagrams I've ever made. (It's my vain suspicion that it had some influence on the Intel hyper-threading ads that previously adorned certain pages here at Ars.) This being the case, I want to develop our general discussion of the types of tasks computers do by first presenting this simple conceptual diagram and then elaborating on it and nuancing it until a more complete picture of the microprocessor emerges.