Software, types, system software, operating system, devices drivers, application software, utilities, Virus, types of virus etc.

1. Software
Lecture #4

2. What is Software
Def#1
• Software is a set of instruction that use to
operates various kind of program.
Def#2
• Software is a generic term for organized
collections of computer data and instructions.

3. Types of software
It is divided in to two major categories:
• System software that provides the basic non-
task-specific functions of the computer.
• Application software which is used by users to
accomplish specific tasks.

4. System software
• Stem software is responsible for controlling,
integrating, and managing the individual
hardware components of a computer system.
• Generally, system software consists of an
operating system and some fundamental
utilities such as disk formatters, file managers,
display managers, user authentication (login)
and management tools, and networking and
device control software.

5. Operating System
• A program that acts as an intermediary
between a user of a computer and the
computer hardware.
Operating system goals:
– Execute user programs and make solving user
problems easier.
– Make the computer system convenient to use.
Operating system Examples:
Linux, Unix, XP ,Windows 7 ,Windows 8.

6. Device drivers
• Device Driver or Software Driver is a computer
program allowing an external extended mother board
components to interact with computer system.
Because of the diversity of modern update hardware
and operating systems, drivers operate in many
different environments. Drivers may interface with;
• Printer
• Scanner
• Sound card
• VGA card
• Network card. Etc….

7. Application software
• Application Software run under System Software , and are made to
do a specific task i.e ( Word Processing etc) , which have indirect
access to the hardware (i.e Behind System Software) .
Examples :
Web browser, word processing software, spreadsheet software,
database software, presentation graphics software.
• Opera (Web Browser)
• Microsoft Word (Word Processing)
• Microsoft Excel (Spreadsheet software)
• MySQL (Database Software)
• Microsoft Powerpoint (Presentation Software)
• iTunes (Music / Sound Software)
• VLC Media Player (Audio / Video Software )
• World of Warcraft (Game Software)
• Adobe Photoshop (Graphics Software)

8. Utilities
• Utility software is a kind of system software designed to help
analyze, configure, optimize and maintain the computer. A single
piece of utility software is usually called a utility or tool. Utility
software should be contrasted with application software, which
allows users to do things like creating text documents, playing
games.
Utility software :
• Antivirus(MC cafee)
• Data compression software (win RAR)
• Disk partitioning
• Backup
• Memory testers
• Network utilities .Etc…

9. Software can be purchased or acquired as:
• Shareware:
– Usually intended for sale after a trial period.
• Freeware:
– Free software but with copyright restrictions .
• Licenses:
A software is a legal instrument (usually by way of contract
law) governing the usage or redistribution of software. All
software is copyright protected, except material in the public
domain
• Key Generator
A license or product key generator (keygen) is a computer
program that generates a product licensing key, serial number,
or some other registration information necessary to activate for
use a software application

10. Virus
• A computer virus is a computer program that can replicate
itself and spread from one computer to another. The term
"virus" is also commonly but misused to refer to other
types of malware, including but not limited to adware and
spyware programs that do not have the reproductive
ability. A true virus can spread from one computer to
another (in some form of executable code) when its host is
taken to the target computer; for instance because a user
sent it over a network or the Internet, or carried it on a
removable medium such as a floppy disk, CD, DVD, or USB
drive.

11. Types of Virus
• Not all computer viruses behave, replicate, or infect
the same way. There are several different categories
of viruses and malware. Below I list and discuss some
of the most common types of computer viruses.

12. Trojan Horse
• Trojan Horse:
A Trojan horse program has the appearance of having a useful and desired
function. While it may advertise its activity after launching, this
information is not apparent to the user beforehand. Secretly the program
performs other, undesired functions. A Trojan Horse neither replicates nor
copies itself, but causes damage or compromises the security of the
computer. A Trojan Horse must be sent by someone or carried by another
program and may arrive in the form of a joke program or software of some
sort. The malicious functionality of a Trojan Horse may be anything
undesirable for a computer user, including data destruction or
compromising a system by providing a means for another computer to
gain access, thus bypassing normal access controls.

13. Worms
• Worms:
A worm is a program that makes and facilitates the
distribution of copies of itself; for example, from one
disk drive to another, or by copying itself using email
or another transport mechanism. The worm may do
damage and compromise the security of the
computer. It may arrive via exploitation of a system
vulnerability or by clicking on an infected e-mail.

14. Types of virus continued ……
• Bootsector Virus:
A virus which attaches itself to the first part of the hard disk that is
read by the computer upon bootup. These are normally spread by
floppy disks.
Macro Virus:
Macro viruses are viruses that use another application's macro
programming language to distribute themselves. They infect
documents such as MS Word or MS Excel and are typically spread to
other similar documents.
Memory Resident Viruses:
Memory Resident Viruses reside in a computers volitale memory
(RAM). They are initiated from a virus which runs on the computer and
they stay in memory after it's initiating program closes.

15. Types of virus continued ……
• Rootkit Virus:
A rootkit virus is an undetectable virus which attempts to allow someone
to gain control of a computer system. The term rootkit comes from the
linux administrator root user. These viruses are usually installed by trojans
and are normally disguised as operating system files.
Polymorphic Viruses:
A polymorphic virus not only replicates itself by creating multiple files of
itself, but it also changes it's digital signature every time it replicates. This
makes it difficult for less sophisticated antivirus software to detect.
Logic Bombs/Time Bombs:
These are viruses which are programmed to initiate at a specific date or
when a specific event occurs. Some examples are a virus which deletes
your photos on Halloween, or a virus which deletes a database table if a
certain employee gets fired.