user interface

The basic structure of an e-mail system. A message is sent via a telephone line and stored in a central computer. The message remains there until the recipient calls up the central computer and collects the message.

In computing, the procedures and methods through which the user operates a program. These might include menus, input forms, error messages, and keyboard procedures. A graphical user interface (GUI or WIMP) is one that makes use of icons (small pictures) and allows the user to make menu selections with a mouse.

A command line interface is a character-based interface in which a prompt is displayed on the screen at which the user types a command, followed by carriage return, at which point the command, if valid, is executed. An example of a command line interface is the DOS prompt.

A menu-driven interface presents various options to the user in the form of a list, from which commands may be selected. Types of menu include the menu bar, which displays the top-level options available to the user as a single line across the top of the screen; selecting one of these options displays a pull-down menu. Programs such as Microsoft Word use menus in this way.

In a graphical user interface programs and files appear as icons (small pictures), user options are selected from pull-down menus, and data is displayed in windows (rectangular areas), which the operator can manipulate in various ways. The operator uses a pointing device, typically a mouse, to make selections and initiate actions.

The study of the ways in which people interact with computers is a subbranch of ergonomics. It aims to make it easier for people to use computers effectively and comfortably, and has become a focus of research for many national and international programmes.