What the Hell is a Computer?

Super quick fundamentals. Just felt like writing it.

Computer?

Computers are integral to all of our lives. Wherever you work, whatever you do, you most likely see or interact with a computer in some form. Most commonly, computers take the form or laptop or desktop devices, however, a computer is anything that takes input, processes that input and then returns output. Any computer can be broken down into five core components:

• Input

• Output

• Memory

• Control

• Arithmetic and Logic Unit (or ALU)

Input Unit

A computer won’t do anything unless you give it something to do. This is typically referred to as a ‘command’. An input device, or input unit can be used to give a command. For example, I’m using my keyboard to write this post, when I press a key it sends input to my computer. Computers don’t speak English, or any human language, so when I press a key on my computer, it is translated by the processing unit to a language that it can understand.

Some basic input devices are:

• Keyboard

• Mouse

• Microphone

Output Unit

This is the result of our input. When I press a letter on my keyboard, it is sent via input, processed, and returned via output. Most commonly, output will be returned on a monitor. When I press ‘a’ on my keyboard, that is returned to me on the monitor. This is output. Imagine a calculator, this is basically a very simple computer. On the calculator, you input “2+2”. The calculator processes this and returns “4” on the screen, this is the computer output.

Some basic output devices are:

• Monitor

• Printer

• Speaker

Memory Unit

Any data inputted to the computer is saved in the memory unit of the computers central processing unit (CPU). When you give input to a computer, it is stored in the memory unit before being transferred for processing. The computer will then process your input, put it back in memory, and transfer it to output. There two basic types of memory: primary and secondary. Primary memory is stored directly in the CPU, whilst secondary memory is stored outside of the CPU.

Control Unit

This is the most essential component of any computer system, it manages everything about the device. When data is entered as input, the control unit sends it for processing. Once the input is processed, it is returned as output to the user by the control unit.

Arithmetic & Logic Unit

Pretty self-explanatory. This handles all mathematical calculations. The ALU can also perform more advanced actions, like comparing data or making decisions. It has circuits which can perform various mathematical calculations like addition, subtraction, multiplication or division. When discussing computers, ‘data’ is the term used for the raw information that is sent to the ALU, ‘information’ is the processed data which is returned to you as meaningful output.

Central Processing Unit

The memory unit, control unit and ALU all make up the Central Processing Unit (CPU). In essence, the CPU is the computers brain. No device connected to a computer can take any action without the permission of the CPU. The CPU is complex and intricate piece of technology, made up of may components that can affect a computer.

Hardware? Software?

When discussing computers, you will frequently hear terms like ‘hardware’ and ‘software’. Hardware is any physical component of a computer, like internal parts, for example, the CPU is a piece of computer hardware. Software is a set of instructions which tells hardware what to do, software is any program on your computer, like a web browser or a text editor.