Central Processing Unit (CPU)
CPUs usually plug into a large socket on the main circuit board (the motherboard) of a computer. They get very hot when they are operating so usually have a large fan attached to their top to keep them cool.
Random Access Memory (RAM)
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.
When a computer is in use, its RAM will contain…
- The operating system software
- The application software currently being used
- Any data that is being processed
Read-Only Memory (ROM)
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.
The general name for these extra devices is ‘peripheral devices’. They are usually categorised into input devices, output devices and storage devices.
Input and output devices are explored more fully in Section 2.
Storage devices are explored more fully in Section 3.
What Are Input Devices?
They all take information from the outside world (key presses, hand movements, images), convert them into data and then send this data into the computer for processing.
What Are Output Devices?
They all take information from the computer and convert it into real world things (images, paper hardcopy, sound).
What is Secondary / Backing Storage?
Secondary storage is non-volatile, so data that is stored on these devices remains there safely.