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
Some examples of Graphical User
Interfaces
Print
Fast Save
Clipboard
Text Justification
These icons
will activate
particular
tools on a
Toolbar
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
Besides
This
example
beingisable
taken
to
from the
select
a command
Microsoft by
Word Toolbar
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