User Interfaces (1.2.t)
Form based interfaces are ideal for software where the operator mainly spends their time inputting various types of data. For example, a telesales operator, who types in order, payment, and delivery details, and then the computer system validates that information, before queuing it for batch processing.
Form based systems prompt the operator to ask all questions in turn, ensures information is input in the correct order (and that nothing is left out), and makes checking of the information easier (as the interface can reject data that does not validate).
Menu based interfaces are useful when the operator may not know all the options that are available - for example at a help desk in a tourist information centre, or the menus on a digital television. A list of choices is made available, and then further lists of choices are based on previous answers. Input is often taken using a touch screen because there are a limited number of choices. Menu based systems should not require the user to be computer literate - they should be very simple. The header navigation for this website is a final example of a menu based system.
Graphical interfaces are formed of four vital components known as WIMP - Windows, Icons, Menus, and Pointer. They allow the user to view applications and files within their own bordered areas, known as "windows". Choices are made using some sort of pointing device, such as a mouse, or sometimes a touch screen. The whole point of a graphical interface is to hide the complicated parts of a program from the user so they do not get confused - by clicking an icon, a user can execute complex code without having to be computer literate.
Natural language interfaces are designed to be like talking to a computer - by asking questions with a limited scope for variation in answers. A good example of a natural language interface is a search engine. A truly spoken version, using voice as opposed to typing, could be used for disabled people.
Command line interfaces are incredibly powerful, but they can also be intimidating to inexperienced users. Although the user needs to understand the commands and how they work, they can then access the entire operating system and the inner workings of the computer. Command line interfaces are not suitable for people who aren't extremely computer literate, but they offer extreme amounts of power and control for people with enough technical expertise.
Good Interface Design (1.2.u)
It is important to design user interfaces well, so that the software is simple and intuitive to use. When designing the user interface, 4 factors should be considered:
- Who the software is for
- What information needs to be conveyed
- The circumstances under which the interface will be used
- The effectiveness of the communication