Software are programs that enable computers to perform tasks by processing instructions. There are two main types: system software like operating systems, utilities, and drivers; and application software for specific tasks like word processing, games, etc. Software can be proprietary, sold commercially, freeware, or open source. It is installed from physical media or downloaded, and some common file types are associated with applications like .doc files for Word.

1. Introduction to
Computer Software
Elike Ike

2. What is Software
Software are sets of computer-
readable codes compiled and design
to enable computer carry out specific
functions. They are also designed to
enable humans communicate
effectively with their computer by
passing simple instructions. The part
of a software that links us to pass
command to the computer is called the
user interface.

3. Types of Software
Broadly speaking, there are two types of software:
• System software
• Application software

4. System SoftwareOperating system, utilities and drivers
• Operating system: this software defines the functions of a computer. They are
designed specifically to coordinate the functions of the hardware, make hardware
accessible to one another and grant application software access to needed
hardware. There are three major operating systems today for computers, Windows
Operating System, Mac Operating System and Linus Operating System. Each one of
these has its own versions (history). For mobile devices, the list is more elaborate
but the most common ones are iOS (iPad and iphone operating system), Android,
windows mobile OS, Blackberry OS, Fire OS and Symbian OS.
• Utilities: these are software that are designed specifically to give the computer user
access to organize, customize and carry out maintenance functions in the computer.
They include things like Disk Manager and Control Panel Items.
• Drivers: these are software that are used to establish linkage between a computer
and connected hardware devices. They assist in describing the device to the
computer and provides information on its functions and available services which in
turn define how the device can be used by the operating and other applications.
These include printer drivers and modem software.

5. Application Software
These are software packages designed to enable computer users carry out
specific functions or have access to computer hardware functionality. Today, the
range of software and their functions is near-endless. Application software are
often designed by companies and groups to address specific computer user
needs. These needs can be to design, to communicate, entertain, educate, data
management, healthcare, security and so on.
The table below shows some common examples.
Developer Name Use
Adobes Photoshop Picture editing
VLC VLC Multimedia entertainment
Microsoft Ms Word Word processing
Mozilla Firefox Surfing the Internet
GNU project FileZilla FTP manager

6. MalwareViruses, Trojan horses, Worms
As the name implies, these are software designed
specifically to cause a computer system to
malfunction. They are programmed often by skilled
developers with malicious intentions. Sometimes also,
specialized agencies use these software as tool to
combat terrorism and disrupt harmful activities. They
often come in a clandestine manner- either within
another legitimate software, adware, within a file, or
through network activities. They are mostly autorun,
that is, they start working as soon as they enter the
desired destination (host machine).

7. SpywareSystem monitors, Keyloggers, Adware
These are software designed specifically to
infiltrate a computer in order to secretly steal
information. They penetrate the computer and
relay the desired information to the hacker
(someone who specialize in secretly gaining
access to computers to steal information).
The information got through spyware are
often administrator access, login details, bank
account Information, official secrets,
confidential materials and so on.

8. Software License Types
• Proprietary: These are software sold/distributed under a registered trademark.
A company develops and makes available these software either at a cost or as
a free to install package.
Commercial/Premium: these are software that are sold to users. The
developer markets the software either in form of cd/DVDs or online to users
who purchase, download and install in their local computers. However,
some offer Trial Version which can be used for a limited period of time or
limited functionality.
Freeware: these are software that are designed and shipped for free such
that one can download them and install without financial commitments.
However, it is expected that the user do not distribute these software to
other users.
• Open source: these are software that are designed primarily to meet user
needs and are offered free to install, distribute and modify. In this case, users
can get access to the raw codes that make up the software for modifications
(mod/tweaking). The Linux operating system is a typical example.

9. Software Installation and Distribution
Software often referred to as applications in this case can be got
and install through two major means:
• Software can come packaged in a CD/DVD drive or stored in a
USB flash from which it can be installed on the computer. This
is common for commercial applications where the seller also
supplies product key or serial number to enable the user
register and validate the installed software.
• Download/Over The Air (OTA): in this process users can
download the software package to their computer from the
developer's website to their computer for installation or install
it directly through the Internet from the developers' host site.
This is a common practice for freeware and open-source
applications.

10. Software Piracy
This is the illegal installation, copying and sharing of proprietary applications
between users. This is a very common practice in Nigeria were people are
wont to copy software from their friends' computer instead of purchasing the
applications. This is an infringement on developers' rights. There are two
common ways of pirating commercial applications. These are:
• Cracks: this is the use of reengineered files to replace the original file that
contains the license documentation of a software in order to confuse the
computer into accepting that the user has purchased the software.
• Keygen and Serial generators: this is the use of specially created
applications aimed at generating serial numbers for a software locally. So,
instead of using the supplied serial number that would have come with the
purchased version of the software, the pirates simply replicate a new serial
number.

11. Files
These are named containers of data/information. They
can hold instructions for the computer (software files)
or data for the user. A file can be the product of
computational process such as the designing of
picture or typed term paper. Files can be created
through the use of application software like Microsoft
Word and Pages.

12. File Types
Each application software has a
particular file type it can create
and those that it can work with.
The files created by an application
is given a unique name after the
user assigned file name known as
the file extension.

13. Some very common examples of file types and
application software that work with them are:
File Type Extension Application
Documents .doc, .docx, .ppt
MS Word and
PowerPoint
Music .mp3, .wma
Windows media
player
Videos .avi, .mp4, .wmv VLC
Note: note all application software generate user readable files. And
not all application can save files to the user directory. For example
Facebook application and Skype.
File Types

14. Nest Class…
Design Principles