How Computers Work

Study Notes

A computer is an electronic device that takes in data, processes it, and outputs the result.
Examples of computers include desktop computers, calculators, mobile phones, smart watches, and iPads.
Input devices such as a mouse, microphone, and Xbox controller send data/instructions into the computer.
Sensors are input devices that monitor changes in their environment, record the information, and send it to a computer.
Output devices such as a speaker, printer, and screen receive information from the computer.

Hardware refers to the physical elements of a computer.
The motherboard sends messages to all of the other components inside the computer.
The processor/CPU is where the computer carries out all of its tasks.
The computer casing holds everything together and keeps each of the components in place.
The power supply pumps electricity around the computer to power all of the components.
The hard disk drive is where all of your documents, pictures, programs, etc. are stored on the computer.
RAM (Random Access Memory) is where the computer stores the current task that is being carried out.
Software is used to describe the programs that run inside your computer.
The operating system is software that manages a computer's hardware and provides a user interface.

The CPU is often known as the processor and is found on the motherboard.
The CPU performs calculations and coordinates hardware (such as the mouse and keyboard).
All CPUs have a clock speed, which is the number of instructions the CPU can process in one second, measured in Hertz (cycles per second).
The Fetch-Decode-Execute cycle is a process where the CPU:
- Fetches program instructions from the RAM.
- Decodes the instructions and makes sense of them.
- Executes (performs) difficult calculations or moves data from one memory place to another.

When you open a program on your computer, you send a message to the CPU to deal with the request.
The CPU looks for the program on the hard disk/long-term storage.
It then takes the program and loads it into the RAM.
The program is now ready to use.

A network is two or more computers connected together to share information and resources.
There are two types of networks: LANs (Local Area Networks) and WANs (Wide Area Networks).
A LAN is a connected set of computers and other devices on one site, relatively small, and owned by the organisation.
A WAN is a wide area network when computers or devices are connected together over a large geographical area.

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