Software - Operating Systems & user interfaces
Points: (Full course)
|Candidates are expected to be able
- identify different types of software
(operating systems, user interfaces, utilities, applications software,
- identify the main features of a
graphical user interface;
- identify the main difference between a
graphical user interface (GUI) and command line
interface, explaining their relative benefits and drawbacks.
Operating Systems Software:
The Operating System (OS) of a computer is the complex software that
the input, output and storage devices of the computer, as well as acting as an
interface between the user and any other software that is installed.
Examples of systems software:
- Microsoft Windows XP, Microsoft Windows NT, LINUX and
UNIX are different operating systems that can be used to control
The following are examples of the functions
that an operating system has to be able to do:
- Allocating a processor 'time slot' for
each programming task that is running
- Managing the priorities for each
programming task that is running
- Allocating and keeping track of the memory
used for storing programs and data
- Managing the transfer of data between
memory and the backing store
- Handling input operations from the
user and from other input devices
- Handling output operations
- Managing the system security
System utility programs work with the
operating system. Examples include programs to format floppy disks, copy files
Types of user interface:
Many computer or database operating systems use complex programming languages
which are not easy to use. A user interface is created to allow easier
control of the operating system by the user of the system.
A good interface should be easy to use, for example:
- consistent menu structures;
- consistent operations from actions like clicking the right mouse button.
Examples of user interfaces:
- Command line interface
(CLI) - commands are
typed directly into the computer and then the enter button is pressed to run
them. The commands must be entered correctly and are often abbreviated. They
can be difficult to remember.
This command would copy a file called 'examplefile.doc' from the hard
drive (drive C) to a floppy disk (drive A).
User Interface (GUI) - This type of interface is sometimes called a WIMP
interface (Windows, Icons,
The contents of folders (directories) and the output from programs
are displayed in rectangular 'windows' which can be moved and resized. Icons
(small pictures) are used to represent files or software and the
mouse can be used to move the icons, run programs and select options from pull-down
- Features of a good GUI:
- Items are placed in similar positions on different screens.
- Navigation between screens is easy and consistent with an escape route
available to return to a main screen.
- Text should be easy to read for all users.
- Screens should be uncluttered with good use made of colour.
Comparing a Command Line
Interface with a Graphical
The user has to know the commands or look them up
The commands are much more intuitive
The commands usually have to be entered in full
Command shortcuts are possible such as <Ctrl> C to copy
The user has to learn the commands and more training is
Less learning and training by the user is required
The interface can be daunting, more difficult to use and
the user is more likely to make mistakes
The GUI is more user-friendly
There are no graphics
Graphics are used to represent tasks, files etc.
There are no menus
Menus are used for making choices and selections
The user has complete control
The user choices are restricted to those on the menus
Commands have to be entered accurately with the correct
spellings and syntax (rules)
Spelling and typing errors are avoided
No pointing device is used
A pointing device is used to select items and make