# Introduction to Computers/What is a computer

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What is a computer? A lesson in Introduction to Computers, a course in School:Computer Science

## What Is a Computer?

A computer is an "electronic box" that you put some "stuff" in, the box does "stuff" with it, and then the box has some way of showing the world what it has done. You are using a computer right now!
The stuff you put into a computer is called data, and gets into the computer using the input. Data is simply a form of information. You can put data into a computer from your keyboard, a mouse, a trackpad, a camera, an infrared sensor; anything that will give the computer more information about the world around it. Based on what information the computer has received, it can decide to do stuff with it.
Input – Data which a computer receives via some input component.
Processing – What the computer does with the data is known as processing. A computer will process information differently based on what kind of data it has gotten.
Program – the computer processes the data we have put in it, in some way - by following a set of instructions: the program. Once the computer has done some processing, there should be a way to show the world what it has done.
Another way to think about a program is if you gave a recipe to a friend, you tell them the instructions and the instructions make the output of the program (or recipe)
Output – This is usually done through a screen, but can also be done with a speaker, LEDs, a laser, a robotic arm; all of these are called outputs.
A basic computer consists of three major components; input/output, the processor, and memory.
Input and output provide a way to interact with a computer:
* Keyboard
* Mouse
* Trackpad or touchpad
* Display
* Power Button
* Microphone
* Camera
The processor, or Central Processing Unit (CPU), is the part that does the processing. The CPU can be said to manipulate data:
* Encryption and Decryption (This makes your data secure.)
* Math
* Logic
The memory gives your computer a place to store information that it might need in order to process data well. The processor can be told to use the memory by specifying it as the input or output. Some things that might be stored in memory might be:
* Photos from a Camera (A camera is an input)
* A Program
* A Text Document
* An Executable Document
The way components inside a computer fit together helps describe how the computer works. Data comes through the Input and is sent to the CPU. The CPU processes the data, normally based on a program or the data which it already has in its memory. For example, in modern computers, when you press the power button on your computer, there is some data (a program) that is automatically sent to the processor from memory. When a CPU is finished processing some data, the result can be sent back to a memory or it is sent to the output.
* Opening an application
* Let's say you're sitting at your computer, and you want to open up Firefox.
* What is the input your computer gets?
* Where does your application come from?
* What does the computer output?

## A Computer-based system

A computer-based system is a system in which a computer is involved and consists of three major elements: Hardware, Software, and User. The elements of a computer based system are described in the three following scenarios:
* Registration in a University
       Hardware = Micro computers, Network platform, and a Server Computer
       Software = Student Registration Application, Database, and Operating System
       User = Operators, Administrators
* Controlling a section of an Assembly Line
       Hardware = A specially embedded system which is developed for this purpose
       Software = The machine code loaded on the embedded system Memory
       User = Other Machine, Supervisor
* Playing a game with a Computer
       Hardware = Game console such as Xbox, Playstation
       Software = The game itself
       User = The game player and maybe AI

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