COMPUTER SOFTWARE
Computer Software is ………….
The general term used to
describe all the programs
which run on the computer.
• A computer needs a program
in order to be able to do
anything.
• A program is a set of
instructions a computer carries
out.
• Software is the general term
for programs or applications
Types of Software
1.System software and
2.Application software
• System software includes:
 The operating system and utility
programs, control how the hardware
of a computer works.
 Programming language compilers/
interpreters;
 Performance monitoring software;
 Some Communications software.
Application software
includes:
 Everyday programmes that
you use such as Word
Processors, Spreadsheets and
Databases.
 e-mail packages,
web browsers and
 Anti-virus software
Operating Systems
All
computers have an
operating system.
It is a program that controls
the computer hardware (e.g.
keyboard, mouse, storage
devices, etc.) and,
 It is the link between the
user and the computer
A computer is useless without an
OS
Hardware
OS
Software
Examples of operating
systems
Windows XP
Windows Millennium Edition
Windows 2000
Windows NT
UNIX
OS/2
Types of Operating Systems
• Single-user Operating systems.
• Multi-users or network operating
systems.
e.g. Network systems are more
complicated as they have to deal with
more than one user at a time.
Need to consider:
 Security
 Access to a central pool of data
 Restricted access to certain files
Functions of OS
• Sorts out where to store data on disk
drives
• Allow the user to organise files using
folders, and to copy and delete files
• Assist applications software to
communicate with the hardware (e.g.
allow a word processed document to
be printed, save and open new files)
• Manage the system resources (e.g.
allocate CPU time to the tasks being
undertaken)
Functions of OS (Cont.)
• Manage the transfer of data to and
from the systems peripheral devices
(e.g. keyboard, mouse, scanner,
printer) and between peripherals i.e
printer/monitor
• Manage system security (e.g.
allocating restricted rights to users
to do certain things through user
names and passwords)
OS acts as a ‘shell’
around the
hardware. The
applications software
need an OS to work,
and users need the
applications software
to interact with the
hardware via the OS.
Operating
system
Hardware
Application
User
Application
Application
User
User
Multitasking and OS
 Multitasking is the ability to do
more than one thing at a time.
 If an operating system can
multitask, it enables a computer
system to do several things at the
same time (e.g. A user can print a
document whilst reading their
emails).
Multi-users and OS
 A multi-user facility allows more
than one user to access data or an
application program at the same
time.
 Without a multi-user facility in an
operating system would be almost
impossible for a computer network
to function.
OS and Utilities
• These are sub-programs used to
maintain the health of the computer
hardware and data.
• They are used as part of, for example :

File Management,

Disk Management,

Memory Management,

Backup,

Data Recovery

Data Compression, and

Anti-virus
Biological Virus
• Not a living thing
• Fragment of DNA inside a protective
jacket
• It can’t reproduce itself
• It uses existing cell machinery to
reproduce itself.
Computer Virus
• Virus is not a living thing but a
small piece of software
• Virus must attached to some
other program or document in
order to get executed.
• Once it is running, it is then
able to infect other programs or
documents
Types of Infections
Normal Virus
• Each time genuine program runs, the
virus runs, too, and it has the chance to
reproduce (by attaching to other
programs)
E-mail viruses
 Move around in e-mail messages, and
usually replicates itself by automatically
mailing itself to dozens of people in the
victim's e-mail address book.
Worms
• A small piece of software that uses
computer networks and security holes
to replicate itself.
• A copy of the worm scans the network
of another machine that has a specific
security hole.
Trojan horses
• A Trojan horse is simply a computer
program. The program claims to do
one thing (it may claim to be a game)
but instead does damage when you
run it (it may erase your hard disk).
Anti-Virus
• A software program that detects and
removes computer viruses.
• E.g Norton, McAfee, eScan, etc.
How to protect yourself?
• Run a more secure OS,
• Use virus protection software,
• Avoid programs from unknown
sources,
• Disable floppy disk booting,
• Enable Macro Virus Protection in all
Microsoft applications,
•Never double-click on an
attachment that contains an
executable that arrives as an e-mail
attachment
Applications Software
• Applications software works through
the operating system to gain access to
the hardware
• Applications software is designed to
perform specific tasks.
• Application software caries out userrelated tasks and can be classified as:
 general-purpose
 specialist (Application or Integrated
packages) or
 tailor-made software.
Explain briefly what the
term ‘General Purpose
Software’ means
List the main reasons why people choose to use
this type of software
General Purpose Applications
• Type of software that can perform
•
•
•
•
many different related tasks
This type of software is sometimes
called generic software.
E.g. Word processors, spreadsheets,
databases, graphics, and presentation
software
It is very popular as it is relatively
cheap, well tested, and has wide
support (e.g. cf manuals and tutorials).
There are ready-made
Reasons for using ready-made
software
It is relatively cheap;
• It is readily available and can be
installed quickly and easily;
• It will have been thoroughly tested
so there will be very little chance of
it having any serious faults or ‘bugs’;
• It will be well supported with a lot of
books about how to use it available
as well as on-line help and
discussions on the Internet.
•
Integrated Packages
• An integrated package
combines many different
types of application together
in a single package that shares a
common set of commands
• They usually include facilities for word
processing, spreadsheets, databases,
graphics, presentation and
communications
e.g. Microsoft WORKS
Integrated Packages
Advantages
• It is cheaper to buy one integrated
package rather than buying several
separate application packages;
• Different applications have the same
user interface;
• Data can be transferred quickly and
easily between applications;
• They are much quicker to install than
several separate application packages
Disadvantages
• Tend to have weak areas (e.g. better
at word processing than spreadsheets)
• Data is not easily moved to programs
that are not part of the package
• Individual applications do not have as
many features compared to the single
application package
Integrated Packages Cont’d
• They have gradually been replaced by
applications bundled together by
software manufacturers and sold as
suites of programs
• Bundled suites have a complete set of
features, a common user interface and
easy facilities for sharing and
exchanging data
• Eg. Microsoft Office XP— database,
spreadsheet, word processing and
desktop publishing software
Specialist Application Software
• Performs a single & very specific type
of task
• E.g Programs to work out payroll,
calculate accounts, plan driving routes,
work out income tax returns, deal with
stock control and handle appointments
Education Software
Educational Software
• These are computer software whose
primary purpose is for teaching.
• It ranges from programs for preschool children, which have a large
entertainment component, to
straightforward typing tutors and
programs that teach foreign
languages or science subjects
Examples of Education Software
• Application(productivity) software
– not originally designed for teachers
but support creative and unusual
learning activities .
• Drills and practice - software that is
characterised by a stimulus-response
approach to learning (Qs-Ans).
• Interactive multimedia - is a
collection of different forms of media,
interlinked to provide coherent access
to information
• Logo - is a procedure oriented
computer programming language
developed for young children to teach
the computer how to perform tasks
• Modelling/ Simulations software to
demonstrate real-life situations
• Helps students learn by doing
Explain what term ‘tailor
made software’ means and
why people might choose
to use this type of software
Give examples of Tailor made software
Tailor-made Software
• Also called Tailor-made, or Bespoke
• Software made for a special purpose for
an organisation (e.g. government,
banks, insurance companies,
manufacturers)
• Especially if not found in the market
• It is very expensive because it is
designed for a specific purpose.
• A long time is taken to make the
programs take to develop
Questions to consider when buying new
software:
• What sort of tasks will the software be used
for?
• How much does the software cost and how
much money is available to buy it?
• What operating system does the software
need? Software will only work with the
operating system that it was designed for?
• What are the minimum system requirements
for the software? Every application package
has a minimum set of hardware requirements
such as how much hard disk space and memory
are needed.
• Will the software be used on a single
computer or on a network?
• How much support is available for
users? (on-line help, telephone
support lines, internet sites and
printed manuals).
• How easy is the software to install —
can an ordinary user carry out the
installation or will an ICT expert be
needed to do it?
Exercise
1. Compare and contrast hardware and software
2. Describe the importance of Operating system to a
computer operation
3. Describe some benefits to be gained from
engaging in hands-on computer learning rather
than reading a textbook
4. Explicate what a file is and justify its importance
in handling computer information.
5. Explain what file management is and how it is
relevant.
6. Imagine you have been employed by a school.
After the school head has seen your UDSM
course coverage, asked you to advice on buying
computers for the school. What advice will you
give in terms of software and hardware. Which
one takes precedence in your decision making
process (hardware or software)? why?