A qualitative term applied to interactive systems (hardware plus software) that are designed to make the user’s task as easy as possible by providing feedback. Ways that help to make a system user-friendly include:

• • a list of valid commands available on request;

• • use of a graphical user interface;

• • ability to undo actions made in error or by accident;

• • use of graphics and colour to indicate what’s going on;

• • availability of a help system giving information appropriate to the current situation;

• • choice of interaction methods to suit personal preference and level of expertise;

• • immediate verification of data input, such as checking that a number is in the correct range or word-by-word spell checking (see spelling checker).

As computers and terminals become available to many more people with no previous experience in the computer industry, it becomes important that only the simplest interactions should be necessary for them to start making practical use of the systems.

The term user-friendly is acquiring a wider ranging application, e.g. to other types of human-computer interfaces, catalogues, and training manuals.