System Design

System Design

1. HCI

   • The engineering process of designing interactive computer systems so that they are efficient, pleasing, easy to use and do what people want.

2. Interfaces

   • Command Line
     • Allows the user to directly input commands which instruct what the computer is to do
     • Used with more experienced users with a knowledge of commands as well as syntax
     • They are fast, direct and use less memory than a GUI
   • Menus
     • User friendly as it's simple and doesn't involve remembering commands
     • In a hierarchical system, further menus are presented until the desired action is identified and selected.
   • Forms and Dialogue Boxes
     • A form is displayed when the user is required to enter data.
     • Examples are: detail about a customer being needed or trying to create an invoice
   • Natural Language
     • In other words "Plain English"
     • In their early stages of development, having limited syntax and vocabulary
     • Advantages
       • No special training as normal dialogue
       • Flexibility and Power
       • Users can construct their own questions and commands
     • Disadvantages
       • Difficulty to keep to a strict vocabulary
       • Precise and formal language is needed
       • Mislead to think the computer is intelligent
   • Graphical User
     • The familiar WIMP (Windows, Icons, Mouse and Pull-Down menus) environment
     • Advantages
       • Speed of learning is increased rather than CLI
       • Confidence from the user and simplicity of the layout
     • Disadvantages
       • Experienced users can take longer to navigate to somewhere they want
       • They need a more powerful processor and a lot of memory

3. Designing

   • Validation
     • After a new computer system has been designed, a check has to be made to ensure the new design is compatible with the original specifications of the system.
   • Review
     • Does the design correspond with the specifications?
     • Does it meet the set objectives?
     • Have the appropriate techniques been met?
     • Is the User Interface appropriate?

4. Criteria

   • Robust
     • Should not crash nor fail
   • Flexible
     • It can be easily reconfigured
   • Reliable
     • Shouldn't fail due to design faults
   • Portable
     • It can be used on multiple hardware systems
   • Maintainable
     • Modifications can be made if needed