Glossary

Classified information is sensitive information to which access is restricted by law or regulation to particular classes of persons. A hierarchical system with several levels of sensitivity is used by virtually every national government.

Closed loop control is a method of automation in which part of the output is fed back to the input to achieve a regulatory action. For example, a closed-loop heating controller might measure a room temperature and switch heating on if the temperature is below target. In contrast, an open control would switch heating on for preset time periods without measuring the temperature.

Cloud computing delivers computing services such as servers, databases, networking, and software over the Internet.

Providers of cloud computing have built many large data centres around the world, equipped with banks of networked computers. They have developed technology to give customers access via the Internet to buy and use capacity as needed, usually on a ‘pay-per-use’ basis.

To access cloud-based systems, all that is needed is a PC or phone and an Internet connection, so businesses can reduce investments in servers and other IT equipment.