Max Learning's Digital Dozen

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1. bit   2. Byte   3. Code   4. Data   5. Program   6. Chip   7. CPU   8. RAM   9. ROM   10. Computer   11. Peripheral   12. System


Chip that Moves & Processes Instructions & Data.
Acronym: Cp = ct-MPID (pronounced See-tee EM-pid).

The CPU (see-pee-yu), or Central Processing Unit, is both the heart and mind of a computer. Like your heart pumping blood through your body, the CPU moves instructions and data through the computer. Like your mind figuring out a problem, the CPU processes data into useful information.

Sometimes the entire computer system is referred to as the CPU. But it's more accurate to think of the CPU as the central chip of an SPU (ess-pee-yu) or System Processing Unit.


Imagine the CPU is a food processor that moves raw food (data) into itself, processes it according to the buttons you push (instructions), then ejects the processed food (information).


I understand your analogy, Max. But if I opened up the computer case and looked inside, would I see instructions and data moving through it?

Actually K.N., the CPU doesn't visibly move anything. What it does do is remotely control millions of switches by sending electrical signals to them, much as you might remotely control your TV set. These electrical signals turn the switches on or off.

A switch that is on allows current to move through it, just as a faucet that is on allows water to move through it. The difference is, you can see the water, but not the electrical current.

The CPU then processes data on its built-in calculator by setting the calculator's switches off or on.

How does the CPU know which switches to turn on or off? It follows the program instructions and data you give it. Without these, the CPU wouldn't know what you wanted it to do.


Imagine the CPU uses a remote control device to set switches, allowing current to MOVE.

 Imagine the CPU uses a handheld calculator to PROCESS data.


The speed at which a CPU operates depends on a companion chip called the CPU Clock. If the CPU is like a heart, the CPU Clock is like the pacemaker that regulates its beat. It contains a crystal that pulses very rapidly when stimulated by electrical current (much like a quartz crystal in your watch vibrates to keep regular time).

On every pulse, data is moved or processed. Naturally, the quicker the pulse, the quicker the computing.

Clock speed is measured in MHz (Megahertz) or GHz (Gigahertz). "Mega" means million, "Giga" means billion, and a hertz is one pulse per second. So a 1 GHz CPU would pulse 1 billion times per second!


Computer Hardware AcroMap--2 of 5 Terms
As you did with the Software AcroMap, start to memorize the following one as we build it. Can you verbally recite what each acronym represents?


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