Human Computer Interface A term used to describe the interaction between the user and a computer. The method by which the user tells the computer what to do and the responses which the computer makes

Importance of good interface design A good interface design ensures that users carry out their tasks Safely – think of a pilot flying a jumbo jet Effectively – operating a video recorder successfully to record the correct program Efficiently – users can obtain money from a cash machine, inserting card and pin, obtaining cash and removing their card Enjoyably – can use a computer program to learn tables, for example

Interface Styles There are a number of interface styles including: Command line interface Menus Natural Language Forms and dialogue boxes WIMP

Command Line Interface Provides a means of expressing instructions to the computer directly using single characters, whole word commands or abbreviations. Very little help is given. Commands enable a user to quickly and concisely instruct the computer what to do User requires the knowledge of the commands available and the syntax for using them Operates via DOS

Menu interface Full screen menu – front end application use. Stays on screen until the user makes a choice. Eg A switchboard on a database Pull down menu – displayed along the top of a screen. When the user clicks on an item, a submenu appears. Always present at the top of the screen whatever screen the user is looking at in the application. Pop-up menu – menu pops up due to a response, say, a click of the right mouse button on a particular area of the screen.

Natural Language – “plain English” Advantages No need for training in a specialised command language Extremely flexible and powerful User is free to construct her own commands, frame her own questions, etc. Disadvantages People find it difficult to stick to grammatical correct English A well designed artificial language can say the same thing more concisely than natural language A natural language can mislead a user into believing the computer is more intelligent than it actually is

Forms & Dialogue Boxes A form is used to enter data, such as customers names. A dialogue box is a special type of form, usually in the Windows environment, for example, a form appears when a print job is set up to the printer. Points to consider when designing a form:- Should have a title to identify it Not be too cluttered – space and blanks are important Corrections should be allowed before the data is accepted Items should appear in a logical sequence to assist the user Default values should be set up whenever possible so a minimum of data entry is required Full help and exit facilities should be provided

WIMP Interface Windows, Icons, Mouse and pull down menus. Window – area on screen through which a particular piece of software or data file may be viewed. The window can be the whole screen or several windows can be set up, each one being moved or resized, as necessary. An icon is a small picture representing an item such as a piece of software. Selected by using the mouse. Mouse moves a cursor, positioning it were required and then selecting the item.