User Interfaces

The human computer interface is what allows the user to communicate with the computer and is often called simply the user interface.

The three main types of user interface are;

• Command-driven;
• Menu-driven ;
• Graphical or GUI.

Menu-driven user interfaces

• Menu-driven systems offer the user lists of options which they can select by pressing a particular key on the keyboard.
• The main advantage of menu-driven systems is that they are easy to use.
• The main disadvantage of menu-driven systems is getting to one particular option can often involve working through many different menu screens.

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Command-driven user interfaces

• To use a command-driven system to communicate with the computer, the user has to type in special command words. DOS, which stands for Disk Operating System, is a very commonly used command-driven user interface.
• The main advantage of command driven interfaces is that they can be quick to use as long as the user knows the correct commands.
• The main disadvantage of command-driven interfaces is that they are very difficult to use if the user is a beginner or doesn’t know the correct commands.
• Command-driven systems can be very unfriendly and confusing for non-computer experts to use.

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Graphical user interfaces

• The most widely used type of graphical user interfaces are WIMP systems.
• WIMP stands for Windows Icons Menu Pointer.
• Options are represented by small pictures or 'icons' arranged inside rectangular boxes called windows.
• The main advantage of graphical user interfaces is that they are very easy to use, especially for a beginner.
• The main disadvantage is the amount of memory space they need. A graphical user interface needs a lot of RAM to run properly and takes up a large amount of hard disk space.

User interface design

A good user interface should be;

• User-friendly; Consistency in operation, screen layout etc;
• Colours should be chosen carefully e.g. that are easy to see;
• Sound can be used to do things such as alerting the user to problems but it should also be possible to turn it off;
• On-line help is often a useful feature