User Interfaces

User Interfaces

1. A way of interacting with machines

2. Command Line Interface

   • Allows the user to interact directly with the computer system by typing in commands (instructions) into a screen.
   • Who uses it?
     • Technician setting up a server in a data centre
     • A mainframe administrator setting up a configuration file
   • Advantages:
     • Faster than others (if correct commands), less memory (RAM), not use as much CPU processing time, low resolution -> cheaper monitor, CLI does not require Windows
   • Disadvantages:
     • Very confusing, commands must be typed precisely, miss-typed instruction = start from scratch, large number of commands, can't guess instruction

3. Menu Driven Interface

   • Allows you to interact with a computer/ device by working your way through screens/menus
   • i.e. iPods, ATM's
   • Advantages:
     • Extremely easy to use, no commands, step-by-step options, guess way around options, can be spoken, don't need huge amounts of processing power/memory, easy to create in different language
   • Disadvantages:
     • If poorly designed can be slow/hard to use, annoying if too many menus, work your way through, can take up large part of screen

4. Forms Interface

   • Can interact with an application by providing limited choices
     • i.e. Setting text characteristics, choice font, size, colour, style
   • Advantages:
     • Easy to program and see options, data validation can be used, fast to enter data, little or no training required, don't need huge amounts of processing power/memory
   • Disadvantages:
     • Limited options, visually impaired trouble seeing text, not good for highly complex applications i.e. tax

5. Dialogue Interface

   • Interaction by speaking
   • i.e. modern cars or 'smart home'
   • Advantages:
     • Allows hands free control, useful for physically disabled users
   • Disadvantages:
     • Limited uses, expensive to develop, training session required, may not operate reliably i.e. background noise, not suitable for safety critical commands i.e. 'stop'

6. Natural Language Interface

   • Allows user to speak or type in their normal everyday language in order to interact
     • i.e. speech recognition software (speech), chat bot (text)
   • Advantages:
     • No training required, more flexibility, suitable for physically handicapped
   • Disadvantages:
     • Reliability is an issue (can only respond to commands that are programmed), highly complex to program, not widely available, voice interference might need training to recognise user

7. WIMP/ GUI Interface

   • Most common type of user interface, friendly as makes use of pictures, graphics and icons.
   • Graphical User Interface
   • WIMP: Windows Icons Menus Pointers
     • Windows: rectangular area on screen where commonly used applications run
     • Icons: Picture/symbol used to represent software application/ hardware device
     • Menus: List of options from which the user can choose
     • Pointers: Symbol (arrow) moves around the screen as you move your mouse, helps to select objects
   • Advantages:
     • Easy to use (especially beginner), easy to explore and find your way around system, do not need to learn commands, usually good help facilities provided, get benefits of WYSIWYG, let you exchange data between different software applications
   • Disadvantages:
     • Take up a large amount of hard disk space, need significantly more memory (RAM), use more processing power, can be slow for experienced programmers (often find CLI faster)