Computer Hardware - Internal Components.     

Motherboard
The motherboard is a printed circuit that acts like the air traffic controller of the computer. It coordinates all the processes, makes sure power is routed properly, and connects all the other components of a computer together. 

The primary thing you’ll notice when you look at any motherboard is that it has a lot of slots and connections.

Since everything is routed through the motherboard, it needs physical contact with nearly all computer components.

That includes main power, the CPU, video and sound cards, all types of memory that the computer may use, and expansion slots.

If you use a mouse or keyboard, they have their own connections, too — along with any other important accessory you might want. .

Central Processing Unit (CPU)
The Core Processing Unit (CPU) is often referred to as the brains of the computer.

While the CPU only makes up one of many processing units, it is one of the most important. It is the part of a computer that performs calculations, actions, and runs programs.

The CPU takes instructional inputs from the computer’s RAM, decodes and processes the action, before delivering an output.

Random Access Memory (RAM)

​Random Access Memory (RAM) is the part of the computer that temporarily stores the instructions that the computer is running, and the data it is processing.

RAM is a volatile storage device. This means that if the computer’s power is turned off the contents of RAM disappear and are lost.

RAM, like the CPU, also plugs in to sockets on the motherboard.

The storage capacity of memory is measured in Bytes.

Usually RAM can hold millions of bytes of data, so you will see capacities measured in:

Megabytes (MB) or 1,000,000 (1 million) Bytes Gigabytes (GB) or 1,000,000,000 (1 billion) Bytes

So, if a computer has 2GB of RAM, it can hold 2 billion bytes of data and instructions at any time.

Read-Only Memory (ROM)

Read-Only Memory (ROM) is used in most computers to hold a small, special piece of software: the 'boot up' program.

This 'boot up' software is known as the BIOS (Basic Input Output System)

This software runs when the computer is switched on or 'boots up'. The software checks the computer’s hardware and then loads the operating system.

ROM is non-volatile storage. This means that the data it contains is never lost, even if the power is switched off.

Compare RAM and ROM

Hard-Disk Drive

The main internal backing store is a computer's hard disk.

A hard disk stores: the operating system software applications or programs the majority of your data files

Hard disks spin at very high speeds (around 7,200 RPM - revolutions per minute) within a sealed unit inside the computer.

Hard disks store large amounts of data - 200 GB to 1TB is common in desktop computers.

​The data stored on a hard disk is retained until deleted, but it needs to be loaded into main store RAM before it can be used.