Popular Science with KBFC: The Computer, Part 1

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My goal here is to give everyone, particularly those who haven't studied Electrical Engineering, a nice little summary of how your PC works. I'm going to try to get into enough detail so that you're not at any time left wondering, "well, that's nice, but how does that happen?" while also remaining completely intelligible to anyone on the forum. I'd like to note that, while I have a degree in Mechanical Engineering with a focus on Electrical Engineering and Computer Science, I'm not an expert on everything EE-related, so it's entirely possible that some EE types might notice some parts that could be touched up; if so, I welcome any additions/corrections. I am completely confident, however, that I will be able to convey all the information accurately enough to satisfy anyone who ever had curiousity about the subject, but wasn't necessarily planning on applying for a job in R&D at Intel.

Black Boxes

The science behind the computer is a large stack of abstractions. In my experience working in the field, most software engineers are effectively ignorant about what happens to their programs once you look closer than the programming language they work in. While I think this is a disadvantage, it is not a huge one; these days, for most applications, it is completely possible to 'black box' all those details away.

What is a 'black box'? People use 'black box' thinking constantly in their everday lives, but probably don't conceptualize it very often, if at all.

When I hit the gas pedal in my car, I know that the act of pressing the pedal isn't directly responsible for the car accelerating - it provokes some complicated reaction in the complicated machinery of the car - but I don't really care. I can drive my car without knowing about any of that; I just know that I press the gas pedal and it goes. It's not only that I don't need to know about every little reaction in my car's engine, it's actually beneficial that I'm not responsible for it. It would be quite the hassle if I had to concern myself with engine timing and combustion cycles (not to mention chemical reactions at the molecular level) anytime I wanted to go to the store, or casino, or strip club (as some would have it).

So anyway, 'black box' thinking is a key factor in not only our ability to operate complex machinery, but also to develop it. As I hope to show in this article, a computer is basically a series of increasingly larger black boxes. The impetus for this post, though, is that while you don't need to know the contents of a black box in order to use one, it might nonetheless be fascinating to find out - I certainly think it is.


I've composed an outline of topic headers that I will most likely follow. You'll notice that the order of topics follows a general trend of "bigger and bigger black box."


Electrons and Semiconductors

A computer is an incredibly complicated device, with billions of parts working in unison to bring twoplustwo.com to you and me. It's all made possible, though, by creative utilization of a special type of material: the semiconductor.


Transistors

Why semiconductors are so special.


Basic Logic Gates

How transistors are used to solve basic logic problems like AND and OR.


Adders

How we can do math using just our basic logical operations.


Memory

How we can store information using basic logical operations.


Scale

How these simple functions scale into our CPUs.


I/O, A/D and D/A

How we tell the computer what to do, and how it tells us the result.


Internet

How we get computers to talk to one another across the world.