User Interfaces_1

User Interfaces_1

1. Menu Driven

2. Special Purpose

3. GUI

4. Command Driven

   • Teletypewriters (TTYs)
   • Video Display terminals (VDTs)
   • Advantages
     • They may be implemented using cheap, alphanumeric displays.
     • More experienced users prefer to have direct control over the operations of the computer.
     • Commands of almost arbitrary complexity can be created by combining individual commands. This allows command macros and command language programs to be written.
     • It is faster to issue a command sequence directly rather than searching through a menu.
   • Disadvantages
     • Users have to learn a command language which is sometimes complex. In some cases few users ever learn the complete language. The learning time for this type of interface is also greater than that for menu systems and GUIs. New users spend more time learning the interface than getting work done on the computer.
     • Users always make mistakes in typing. This requires error handling and message generation facilities to be included in the command language processor. Systems interaction is through a keyboard. The interface cannot make use of pointing devices.
     • For a novice it can be quite daunting and difficult to get even the simplest of operations performed.