AS Level ICT

Selection and use of appropriate software: Interfaces

What is software?

• Software is the name given to all the programs that run on computer hardware

• There are two main types of software:– Operating software (also known as systems

software)– Applications software

User interfaces

• The way in which a computer user communicates with the machine is called the Human-Computer Interface (HCI) or User Interface

• The user interface an important function of any type of software regardless of whether or not it is an operating system or an application

User interfaces

• A good human-computer or user interface needs:– To be user-friendly– To be attractive to use– To be effective– To be easy to use

User interfaces

• A user-friendly interface should make it possible for the user to use the software without having to read the entire manual first!

• An interface that is attractive to use will also encourage users to use the software

User interfaces

• An effective interface will do its job efficiently• An easy to use interface will have menu structures

that are consistent in design and layout across several different software packages (e.g. the fast save option will be in the same place on the toolbar and have the same icon)

User interfaces

• The main types of user interface are:– Command line/driven interfaces– Graphical User Interfaces– Menu-driven interfaces, including

• Toolbars• Drop-down menus• Pop-up menus

– Combinations of the above

Command line/driven interfaces

• Before the introduction of GUIs by Apple Mac and Microsoft, computers had to be given commands in DOS

• These were typed in, and often used abbreviations• The commands had to precise and correctly

worded in order for them to work

An example of a command line/driven interface

This example is the command used to view the directory of all the programs and files in ‘Windows’

Command line/driven interfaces - Advantages

• Command line/driven interfaces have the advantage of being quicker in certain circumstance

• Sometimes it is quicker to type in a command line than to use a mouse and a menu-driven interface

• By using the arrow keys, the previous commands that have been entered can be made to reappear, thus saving the user time because they don't have to type it again

Command line/driven interfaces - Disadvantages

• Command line/driven interfaces require the user to learn the correct structure (or syntax) of commands

• They also require the user to remember the instructions/commands needed for particular tasks

Command lines

• Many computer users use command lines without realising they are

• For example a URL (universal resource locator) uses the syntax and commands of a command line (e.g. http://ict-teacher.com/index.html is the URL for a website; it is also a command line that ‘tells’ the computer to use a hyper-text transfer protocol to search the internet for the index page of a website with the address ict-teacher.com)

Command lines

• Icons are short-cut ways of using command lines• The properties of a icon show the command line

that will be enacted if the icon is ‘clicked’

Command lines

The control line used to launch Encarta Premium is:

C:\Documents and Settings\All Users\Start Menu\Programs\Microsoft Encarta

This is activated when the Encarta Premium icon is clicked

Command lines

• It is worth noting that command lines are still used by programmers (e.g. Visual Basic, Javascript, SQL) and website designers (e.g. html)

• They are still an important part of work done by ICT professionals

Graphical User Interfaces

• GUIs are very popular because they are easy to use

• The main features of GUIs include:– Windows – the screen is divided into several

areas, called ‘windows’, thus enabling a user to have several tasks ‘on the go’ at the same time

– Icons – small images are used to represent commands, files, or windows; when clicked they activate whatever they represent

– Menus – drown-down or pop-up lists of options available to the user

Graphical User Interfaces

– Pointers/Cursors – these appear on screen either as an arrow (when using Windows) or ‘I’ shape (when using word-processing software); they are moved using a ‘point-and-click’ device (e.g. mouse, light pen)

– Desktop – this is the onscreen working area where the icons are situated

– Drag and drop – this function allows objects (icons, folders, files, documents) to be dragged from one area to another (e.g. a document can be moved from one folder to another)

Graphical User Interfaces

– Taskbar – this shows the programs that are currently being used

• Any windows-based graphical user interface can also be referred to as a WIMP – Windows, Icon, Menus, Pointer

Some examples of Graphical User Interfaces

These icons will activate

particular programs

Microsoft Word

Outlook Express

These icons will activate particular tools on a Toolbar

Print

Clipboard

Text Justification

Some examples of Graphical User Interfaces

Fast Save

Some examples of Graphical User Interfaces

Microsoft Word

Microsoft Excel

Microsoft Access

Note the use of Icons that are common to all the toolbars

Fast Save, Print, and Print Preview Help

Graphical User Interfaces - Advantages

• They are not language dependant – the user does not need to type in commands

• They use icons – inexperienced users can select and use different functions merely by pointing at and double clicking on an icon

• They work well with point-and-click devices, particularly a mouse

Graphical User Interfaces - Disadvantages

• GUIs use a lot of memory – modern GUIs use considerably more computer memory than command line/driven interfaces and are incompatible with older, less capable computers

• GUIs require increased levels of processing power – faster and more powerful processors are needed in order for GUIs to function fully and at a fast enough speed

Menu-driven interfaces

• Menu-driven interfaces give the user a list of options from which to choose

Some examples of Menu-driven interfaces

Some examples of Menu-driven interfaces

Menu-driven interfaces

• They are often combined with Graphical User Interfaces

Some examples of Menu-driven interfaces – Drop down menus

Note that options that are not available are ‘greyed’ or ‘ghosted’

Some examples of Menu-driven interfaces – Pop up menus

The Microsoft Windows

‘Start’ Menu pops up when the

‘Start’ button is pressed

The ‘AutoShapes’ Menu in Microsoft Word

pops up when the ‘AutoShapes’ button is

pressed

Menu-driven interfaces – Advantages and disadvantages

• Their main advantage is their simplicity• Their main disadvantage is they are only suitable if

the list is not overlong

Other forms of interface

• There are other forms of interface including:– Key-driven interfaces– Form-driven interfaces– Natural language interfaces

An example of a key-driven interface

This example is taken from the Microsoft Word Toolbar

Besides being able to select a command by clicking on the appropriate word with a mouse, these options can also be selected by the use of the keyboard

For example:

Pressing the ‘Alt’ and ‘f’ keys at the same time selects the File option

Pressing the ‘Alt’ and ‘o’ keys together at the same time selects the Format option

Form-driven interfaces

• Form-driven interfaces are used to collect data, and are usually the ‘front end’ of a web-supported database

• They are designed to collect the data by taking the user through a series of steps, and indicate which fields must be completed and which are optional

• They include validation checks to ensure that the user can only enter data that meets the specific rules

Form-driven interfaces

The stars indicate fields that the user must complete

Natural language interfaces

• Any interface that allows the user to interact using natural written or spoken language (e.g. English) are known as natural language interfaces

• The most common natural language interfaces are Internet search engines (e.g. Google) where the user enters key words that they wish to search for

• The advantage of this type of interface is the ease with which users can interact with it

• The disadvantage of this type of interface is the complexity and ambiguity of natural language

Natural language interfaces

AS Level ICT

Selection and use of appropriate software: Interfaces