How Computers Work [From the Ground Up]

In the seniors' computer club, when asking for new topics to cover in the new year, somebody asked me to address how computers work.

Since I've been asking myself the same question, for over five decades, and I'm still quite sure that I don't fully understand how it all works, and since I've been teaching how computers work for at least four decades, initially I thought this might be a non-trivial task.  Remember that this is for a bunch of seniors, from a town where neither the high school nor the college have any computer courses aside from graphics for games.  So it can't require any technical sophistication, and it should be available for the general public, for business people, for students, even at the elementary grades, and for anybody who is interested in how the computers that run our world actually work.  I have seen lots of attempts, by various people, to explain how computers work, and mostly what they demonstrate is that the instructor really doesn't understand how computers work.  The results tend to be non-illuminative, and generally pretty boring.

I once took a course on computer architecture with a bunch of doctoral students in computer science.  We were divided up into groups and the groups gave presentations on different aspects of computer architecture, with the individual members of the groups covering particular topics.  My group was addressing the most fundamental aspects of computer architecture, and I was addressing the use of electrical circuits to create logic circuits, and why sometimes using the seemingly most straightforward circuit was wrong, and that complicated gates were often, counterintuitively, faster and more power efficient than taking the seemingly obvious route.  After my presentation I started to get what I considered to be really strange questions, and at one point I got frustrated and burst out "You do know that when you create an electrical circuit you have to have a source, and a sink, and a constant and continuous path between them, don't you?"  After the class in which our group had done our presentations I was talking with the leader of our group and I apologized for losing my temper and said that I shouldn't have assumed that they didn't know such an obvious and basic fact.  "Oh no," she replied, "that was useful!  I didn't know that!"

I have learned a bit in all that time.  And, mulling it over, using all that I had learned over more than fifty years, I started to get a few ideas of how this might be done, and done effectively.

So, as an addition to my (generally failed) attempts to provide seminars and workshops to the churches in town, so that they could then provide presentations (such as security for seniors, the Jesus Film Festival, dealing with depression, grief resources, and public art in Port Alberni) that might draw in the unchurched, allow me to propose to you "How Computers Work [From the Ground Up].  (I even have a sermon  that might start it off.)

Computers run our lives. We use computers for our work, pretty much regardless of what our work is.  We carry computers around in our pockets, pretty much all the time.  Computers handle our communications with each other, our social activities with each other, our reservations for restaurants, hotels, and airlines, and computers mediate pretty much everything that goes on in our lives.  It would probably be a good idea to find out how they work.  Starting with how to build devices and circuits to do logic, and how to do logic to do calculations and to hold information in memory, a series of possibly eight to ten one-hour presentations cover how computers work, how they do what they do, what they can do, and what they can't do.  This isn't just how to use common computer tools.  This is a basic understanding that lets you know what tools computers can build.  What tools can be built with computers, and what can't.  And, how they operate, right from the ground up.  When this series is over, possibly you won't be able to take a box of transistors and build your own computer, but you will have enough information to go and learn how to do this if you want to.

This is still a work in progress, but topics include:

 - In the beginning ...

 - COMPUTERS ARE NOT MAGIC!!!

 - Logic

 - Memory

 - Computers do two things ...

 - Programs

 - Data Communications

 - Networks (and how to do *everything* *MUCH* cheaper!)

This series is going to be technical, in the sense that I'm providing technical information and explanation, but it's not going to be technically demanding.  There aren't any prerequisites.  I'm going to begin with the supposition that the audience is not going to know anything about how computers work.