Desktops, Laptops, Tablets, and Smartphones are all computers
Whether or not you notice it, computers are everywhere you look. Chances are you use them every day. When someone says the word “computer”, you might imagine something like the picture on the right. This is called a Desktop Computer. We will start by looking at this example of a computer. Then we will look at laptops, tablets, and smartphones to see how they are similar or different. First, we are going to look at how a desktop computer is similar to the human body.
You have a skeleton; a computer has a chassis
A computer has different parts just as you have different body parts. You have a skeleton that protects all your important body parts from damage. A computer has a skeleton, or chassis, which is the housing for all of the components. It can be made of either plastic or metal, or sometimes both.
The brain of a computer is called a CPU
A desktop computer also has a “brain” that does all of the thinking the way you have a brain. This “brain” is called the microprocessor. It is also known as the CPU, or the Central Processing Unit. The CPU has the instructions for running the computer. It reads the memory and translates what the memory has to say into instructions that the rest of the computer can understand. Just like the brain, this job is necessary for the computer to do anything.
You have memory - so does a computer
Your brain can store memories. That's why you can remember how to tie your shoes, and that your mom asked you to take out the trash. A computer can store information, too. Computers actually have a few different ways to store information. Information that needs to be kept when a computer is shut down is kept in some type of non-volatile storage. Non-volatile in this case just means that the information is kept when the power is off. There is also working memory whose contents do not need to be kept when the computer is turned off. Non-volatile storage includes something called Read Only Memory, or ROM
, which generally has a small amount of key information for the computer. Non-volatile storage also includes the computer's hard drive. Working memory is often called Random Access Memory, or RAM
You have a hearbeat; a computer has a clock
What does your heart do? It beats and keeps everything in your body running. This is exactly what the clock in a Desktop Computer does! The clock keeps time and ensures that all the different “body parts” of the computer’s “body” run in sync with each other. But if your heart stops beating, what happens to you? Your body dies! The same thing happens to a computer’s system if the clock stops or breaks. The clock is essential to any and every computer.
You have a voice and gestures for output; a computer has speakers and a display
If you want to tell someone something, you have a voice box. Your voice allows you to speak and communicate to other people. Computers have speakers inside that can beep or make noises when things happen. For example, you might hear a chime when you get new email messages. Or, the computer might beep at you if you try to do something you are not allowed to. Sounds from the speaker are one way that the computer can generate output
. Output means something that the computer does to put information out.
The computer screen itself is another type of output. The screen shows you want you are doing. It might also give you messages, such as suggesting spelling changes, or telling you that something has happened. You might think of this type of non-audio output as being similar to your gestures.
You have five senses; a computer takes input from a keyboard, mouse, maybe even a touch screen
Your body gets input from the world around you. For example, you can read instructions on your homework. You can hear adults in your life asking you to do something. You can smell when lunch is close being served. Sight, hearing, touch, smell, and taste are your inputs.
Computers take their outside input from things like a keyboard, a mouse, voice commands, or a touch screen. Those are a computer's sensory inputs. In the computing world, information that comes into a computer or program are called inputs
A computer has a communication channel to carry signals, like your nervous system
Have you ever heard of your nervous system? Your nervous system is a communication network for the human body that carries information from our brain to parts of our body. The computer has lots of copper traces that go throughout the entirety of the printed circuit boards, and they act like a nervous system. They carry electrical signals that help the different parts of the computer understand and communicate with and to each other. The communication system that carries information between parts of a computer is called the bus
A computer needs an energy source, just like you do
Every electronic device needs a power source, whether it is a battery, a solar panel, or for a desktop computer, a thing called a power supply
. You plug the cord into a wall outlet. This cord plugs into the power supply. The power supply carries the power from the wall into the computer. The power supply changes the power to something it can use. It also divides up the power so that each piece of the computer gets the amount of power it needs. If you open up the computer, you will see dozens of wires sticking out of the power supply, to carry power to all the parts where it is needed.