User interfaces

GOOD DAY, students. This is lesson six in our series of lessons. In this week’s lesson, we will examine the various types of user interface.

The interaction between end users and the computer is said to take place at the ‘human computer interface’ (HCI) point. The term ‘human computer interface’ is meant to cover all aspects of this interaction, not just the hardware. One of the most important features normally required in an HCI is that it be ‘user-friendly’. As the name suggests, a user-friendly interface is one that the end user finds helpful, easy to learn and easy to use. It is easy to recognise unfriendly interfaces, but not so easy to design one that is certain to be user friendly.

THE MAIN TYPES OF USER INTERFACE

The user interface is made up of a hardware interface and software interface.

HARDWARE INTERFACES

Hardware interfaces are special devices with additional features that will allow easier interaction process for the user.

Hardware interfaces would include the use of following:

■ Touchscreens (you learnt about this when we covered input devices).

■ Specialised keyboards– Such special keyboards include:

(a) Ergonomic keyboards – These keyboards are shaped in a particular manner that is more comfortable to use. This can assist with the avoidance of injury that may occur during repetitive usage of the keyboard, like typing.

(b) Overlay keyboards – This keyboard replaces the traditional keys with a flat touch-sensitive panel. These keyboards are very useful for children and adults who cannot manage a normal keyboard.

(c) Braille keyboard – These are utilised by blind individuals.

■ Sensors – This is quite useful in providing interfaces for persons who cannot use standard devices such as keyboards. A user with very limited movement can use a device with a sensor, which he/she can press with a finger or a foot, or by moving the head.

■ Non-visual interface components – Examples of these interfaces include speech synthesis and voice recognition.

SOFTWARE INTERFACES

Software interfaces would include the use of following:

■ Command-driven interfaces

■ Menu-driven interfaces

■ Graphical user interface Note: In some situations, two different types of interfaces may be combined; for example, a menu interface with command options. Let us examine in more detail the three main types of software interfaces.

COMMAND-DRIVEN INTERFACES

One of the long-established methods by which users can interact with the computer is by the use of commands. Commands enable the user to quickly and simply instruct the computer what to do. However, they require the user to already have knowledge of what commands are available, what they do, and the rules governing how they should be typed, so they are more suited to experienced users than the end user. A technical person, such as a computer operator or programmer, would be familiar with the commands, or where the end user continually works with the same program and, therefore, can gain mastery of the commands.

ADVANTAGES OF COMMAND-DRIVEN INTERFACE

1. Faster to use once you have learnt the commands.

2. For a computer programmer, command-driven interfaces are cheaper to implement.

DISADVANTAGES OF COMMAND-DRIVEN INTERFACE

1. It is sometimes difficult to remember all the commands; therefore, users have to constantly refer to the software user manual.

2. The user is restricted to using only the keyboard as the interfacing device, while with other interfaces, a wide variety of input devices can be used.

3. Commands must be entered at a special location on the screen and in a set format.

MENU-DRIVEN INTERFACES

Menus provide another popular form of user interface. There are many different alternative forms of menus. The simplest menus provide the user with a number of options and a simple means of selecting between them. The user is presented with a choice and, therefore, does not have to remember any commands. The interface is, therefore, suitable for beginners and infrequent users. All the user has to do is to make a choice.

A special type of menu is called a pop-up menu; an additional submenu pops up as a selection is made. You can click anywhere on a given document using the right-click mouse button to allow a pop-up menu to appear.

Pull-down menus are a special type of menu used in windowing and were briefly introduced. It is a menu displayed as a vertical list which hangs from a horizontal bar on the screen in order to elicit a choice from the user.

ADVANTAGES OF MENU-DRIVEN INTERFACES

1. The user is presented with a list of options to choose from and does not need to remember the commands.

2. They are free from typing errors, because the user does not have to type the commands.

3. A wide variety of input devices can be used to interface with a menu.

DISADVANTAGES OF MENU-DRIVEN INTERFACE

1. Several steps are required to issue a command.

2. Once the user has learnt the menu system, it is bothersome to have to wait on the package to present the questions before the commands can be entered.

GRAPHICAL USER INTERFACE

A graphical user interface (GUI, commonly pronounced ‘guey’) is a human computer interface based upon a graphical display. GUIs are most commonly found on workstations or PCs fitted with graphics adapters able to support high-resolution graphics. GUI is a variation of the menu-driven system of selecting commands with the use of the mouse, and pointers, along with the use of windows. Thus, this interface is often summarised using the acronym WIMP, which stands for windows, icons, menus (‘pop-up’ and ‘pull-down’) and pointers. A mouse is used to click on an icon to execute some operation or select options from a pop-up or pull-down menu.

ADVANTAGES OF GUIs

1. Its user-friendliness results in less anxiety on the part of the user.

2. Icons/symbols are easier to recognise and provide the user with a context.

3. There are fewer command errors.

4. They reduce typing.

5. They are convenient to use by a novice.

DISADVANTAGES OF GUIs

1. It may consume more screen space.

2. For programmers, the design of graphical user interface is more complex.

3. Increased use of computer memory can lead to slower processing.

We have come to the end of lesson. See you next week. Remember, if you fail to prepare, you prepare to fail.