User Interfaces

User Interfaces

1. Command Line Interface

   • Common Uses
     • MS-DOS
       • BBC Micro
         • Quest database
   • Advantages
     • *Select options using lots of menus.
     • *An experienced user who knows a package well can enter commands quicker
     • *Can be used on a computer which has very little memory and is slow.
   • Explanation
     • An interaction with a computer using a command line interface usually follows these two steps:The user types a command , The computer carries out the command and displays its results.
   • Disadvantages
     • *It is very difficult to remember all the possible commands and exactly how they should be typed.
     • *Error messages are not usually very helpful.
     • *Have to be an experienced user to understand it

2. Graphical User Interface

   • Common Uses
     • Windows
       • Risc-Os
         • Any piece of software running under one of the above operating systems.
   • Advantages
     • *Greater Accessibility you have more capability at your cursor tip
     • *Less skill is needed to work it
     • *Higher Productivity
   • Explanation
     • When you use a program such as a word processor that has a WIMP interface it is often the case that the document you are creating looks exactly the same on the screen as it will when it is printed out. If this is the case then the program is described as being WYSIWYG. This stands for What You See Is What You Get.
     • Window: An area of the screen which is used to display a particular program or piece of work. Many windows can be displayed on the screen at the same time.
       • Icon: An informative picture / symbol displayed on the screen which the user chooses to select an action. Icons can usually be used to represent software packages, documents and hardware devices.
         • Menu : A list of options which the user can pick from. Menus can be pull-down (selected from a menu bar at the top of the screen) or pop-up (selected by pressing a mouse button).
           • Pointer: A symbol such as an arrow which is moved by a pointing device and can be used to select objects.
   • Disadvantages
     • *Takes up a lot of memory
     • *If you have a slow computer, it may work slowly or not at all.
     • *Need to be run on a fast computer

3. Menu Driven Interface

   • Common Uses
     • Wordwise word processor
     • A bank cash point machine
     • Grass database
   • Advantages
     • *The user does not need to remember and type lots of commands.
     • *Menus contain explanations of the options that are available
     • *You can guess how to use a program without having to refer to a user guide because its so simple and easy to use
   • Explanation
     • A typical program will have many menus which the user can access.Menus can be either full screen or pull-down. Pull-down menus are accessed by selecting the menu from a menu bar. Pop-up menus are activated by pressing a button on the mouse.
   • Disadvantages
     • *You may have to switch screens to access a menu.
     • *Certain operations/options cannot be ‘visual’
     • *Can be time consuming to find a command if unfamiliar with software