Subtitles of the Movie

Now let's dig into the pieces and parts of the PC and let's start to ah take this thing and um, simplify it, and see how it all works. First of all, what is a CPU? Well, it's the Central Processing Unit. Now you will hear this a lot of times called the brains of the computer, or you'll hear it referred to as the little man in the computer, and there's something in our genes. Ah, as I have taught ah classes all over the country it is amazing to me how many people come to computer class and they don't know anything about a computer, but they all talk about the little man in the computer. I don't know where we got that, but it's kind of wired into all of us. The two most popular ah processors on the market, Intel and AMD. I've got a, ah server box with Intel in it, and a laptop with AMD and I like them both, so I'm going to stay out of that fight. But, what the processing is, central processing unit, or CPU actually does, is it carries out instructions, and usually it's, it's doing everything from any kind of calculations to, to mapping things, and so forth, and so it's where all the quote thinking takes place, and really it's not thinking, it's just following instructions. Now, modern processors can do billions of tasks per second, so they're really, really quick. They're not really smart as much as they're just really quick. Now, let's talk about logically what's happening with the CPU. Now this is like horrible, horrible over simplification, okay, but it will give you an idea of what's happening. Now, let's go with the little man in the box idea. Let's say there's a little man in the box in the CPU and we need him to do a mathematical calculation, or we need him to carry out some other task, okay. So one of the things is we need for the, the parts outside the CPU to be able to talk to the CPU and instruct the little man inside there what we need him to do. So let's picture that we put, for right now, six light bulbs inside the box, and six light bulbs outside the box, and we're going to connect these light bulbs, and what we're going to do is, when we want to send a message to him on the inside we will simply turn on lights so the ones we turn on out here get turned on in there, so he can see the lights, and based on the pattern that the lights are on it can send him messages. It's almost like a visual Morse Code, if you will. And so by turning on certain lights and turning off certain lights we can give him instructions and he can carry those out and then he can send us a message back out by turning on lights. Now, I want you to think about something. Do you remember when we talked about binary in a different video? Isn't this really the same thing, because notice for these six bulbs that we have here, we've turned two on, and based on the position you can see here that I've passed in at the number 10. Notice, and if you remember your binary, this one means one, this one means two, this one means four, this one means eight, so eight plus two is ten, so I've told the man inside the CPU that we're doing something with 10. Okay. Now, what's really is going on with the CPU is, is that we actually pass instructions into the CPU in this form, and notice here's two lines or, or, or two codes that were actually part of one of the early processors that if we passed in, and notice this is using 8-bits, we've got a 6-bit example here, but with 8-bits, if you passed in a 101, 110, 10, it told the processor that the next line of code that comes in is a number, and that would have told it in our instance this is what's coming next and treat it as a number and it would have known it was the number 10. The next one, 01, 000, 001, instructed the processor add one to the number that you already have. So had we passed in this, and then this, we would have had 10 in here, and then it we would have passed this, it would have added one, we would have had an 11 in here. So you can see this is all very logical, however, it's happening very, very quickly. Now, Intel did something that was, um, kind of fundamental to the architecture of, of ah their processor, and they included registers, AX, BX, CX, and DX registers. Now really what they did, I'll go back to my previous ah primitive example, the little man inside the box. Picture that as AX, BX, CX, and DX. These registers are work tables if you will. And so, the little man has four different work spaces to work on. Now in reality, each one of these work stations has thousands and thousands of bulbs, so the little man inside there can create some very complex messages and can keep track of quite a bit of data. Okay, so that's what's happening inside the CPU. The CPU sits there and it carries out instructions and any time any other object on the motherboard needs something calculated, or any kind of instructions carried out, it ah, it contacts the CPU and it begins to speak in binary to the CPU and pass binary information in. The CPU processes that, hence the name Central Processing Unit, and then passes the result back out. Now, let me back up just a second and let's look at our previous example. These lines right here, from the outside world into the processor, are known as the bus, and, and they're used to bus information in and out. And so that's another term you may hear about the CPU. So that's, that's a very crude, primitive example, but I hope it helps you understand exactly what's going on in the computer with the CPU. Now, coming up next, in the next video, I want to talk about clocking, because this is a great idea. However, we need to talk about how clocking comes into play and how it makes the CPU work, not only efficiently, but makes it work at all.