Glossary

Binary

A system limited to having just two values.

Computer bus

The internal data connections across the input and output subsystems and the secondary memory subsystem to the computer’s processor and main memory.

Computer system

Formally a processor and its associated devices to make a usable ‘system’, but often the complete system, is referred to as a ‘computer’.

Digital

In our context, it means systems using discrete rather than continuous values. In the larger contest of computers in society, there is also the social and marketing use of ‘digital’, where it represents a way of engaging with people.

Embedded computer system

Specialised processors acting as controllers for devices such as washing machines and microwave ovens.

Hard disk

A form of secondary memory consisting of one or more rigid magnetic disks rotating about a central axle. Also known as a hard drive.

Hardware

The physical components of a computer or computer system.

Input-output device

A component that can function both as an input and as an output device.

Input-output subsystem

The components of a computer system responsible for the retrieving, transforming and presenting the data used by a processor, functioning as both an input subsystem and an output subsystem.

Input subsystem

The components of a computer system responsible for the entry of external data and its transformation into a form the processor can use.

Main memory

Where a processor stores instructions and associated data for execution.

Microprocessor

Was introduced when processors were first made on a single silicon chip, with the prefix ‘micro’ emphasising their small size

Output subsystem

The components of a computer system responsible for the transforming and presenting the data used by a processor into a form for use outside the computer system.

Secondary memory

Holds programs and data that will persist after the computer is switched off.

Secondary memory subsystem

The components of a computer system that prepare data for and retrieve data from secondary storage.

Software

The program, or collection of programs, that enable a computer to carry out its tasks.