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Course: CSC103 Fundamental Computer and Applications

Basic Software Concept

Lecture Notes 3

Outline

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What is an application?

Types of desktop applications

Mobile apps

What is a web app?

Computer Security Software

System Software

Operating system

What is an operating system?

The operating system's job

Types of operating systems

Getting to know your computer's OS

Operating systems for mobile devices

Protecting your computer

Software:

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Software is a term used to describe a computer program, which is a set of instructions

that tells the computer what to do.

Software consists of computer programs, which are sequences of instructions for the

computer.

The process of writing (or coding) programs is called programming, and individual who

perform this task are called programmers.

Figure 4.1 Systems software serves as Intermediary between hardware and functional

applications.

Types of software

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Software can be split into three categories. They are:

Programming software

Operating system software

Applications software

Programming software. This software is used by computer programmers to help

write computer code. Like C, C++,Java,C#.

Applications software:

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Application software is a program or group of programs designed for end users.

Types of desktop applicationsMicrosoft Office

Microsoft Word

Microsoft Excel

Microsoft PowerPoint

Adobe Photoshop

Multimedia Software

Enterprise Software

Information Worker Software

Educational Software

Mobile Application:

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A mobile app is a computer program designed to run on smart phones, tablet

computers ,android and other mobile devices.

Some of key areas of app development include

Gps Enable Apps: Among the several rich features available in smartphones today,

one of the key features is GPS enabled Geo-Location. Now what is Geo-Location you

may ask? Geo-location simply put is the identification of the real-world geographic

location of an internet-connected device. In other words, with your smartphone you can

locate your current latitude and longitude through internet anywhere in the world.

Some of key areas of app development include

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Social Networking App:

Social Networking and Smart phones are increasingly becoming tightly coupled and most

new phones are now pre-packaged with social networking integration. With multi-touch

screen, GPS functionality and feature rich app development kit, smart phones are ideal

devices for Social Networking Apps

Gaming Application:

Gaming apps are downloaded more than any other category of apps. This accounts for

millions of dollars in revenue for the most successful gaming apps. Even the lesser

successful gaming apps are capable of generating significant revenue from downloads or

from advertising.

Some of key areas of app development include

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Mobile Website:

Although, not as popular as native applications, mobile websites are a good way to

extend your already existing presence on web, to a mobile platform. With the advent of

smartphones, browsing the internet on a mobile phone has become a commonplace.

Web Application & Web browser

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Web Application:

A web application or web app is any software that runs in a web browser. It is

created in a browser-supported programming language (such as the combination of

JavaScript, HTML and CSS) and relies on a web browser to render the application.

Web browsers - These programs allow users to navigate the Internet. Some of the

more common ones include Microsoft Internet Explorer, Netscape Navigator,

Mozilla Firefox and Apple Safari.

Different kind of Computer Security Software:

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How Do I Improve the Security of My Home Computer? 1. Connect to a Secure Network

2. Enable and Configure a Firewall

3. Install and Use Antivirus and Antispyware Software

4. Remove Unnecessary Software

5. Disable Nonessential Services

6. Modify Unnecessary Default Features

7. Operate Under the Principle of Least Privilege

8. Secure Your Web Browser

9. Apply Software Updates and Enable Future Automatic Updates

10. Use Good Security Practices

System Software

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System Software:

System software is a type of computer program that is designed

to run a computer's hardware and application programs.

What is an operating system?

An operating system is the most important software that runs

on a computer. It manages the computer's memory, processes, and

all of its software and hardware. It also allows you to

communicate with the computer without knowing how to speak

the computer's language. Without an operating system, a computer

is useless.

The operating system's job

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Your computer's operating system (OS) manages all of the

software and hardware on the computer. Most of the time,

there are many different computer programs running at the

same time, and they all need to access your computer's

central processing unit (CPU), memory, and storage. The

operating system coordinates all of this to make sure each

program gets what it needs.

Types of operating systems

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Microsoft Windows

Apple Mac OS X

Linux.

Windows XP

Microsoft Windows

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•Microsoft created the Windows operating

system in the mid-1980s.

•Over the years, there havebeen many different

versions of Windows, but the most recent ones

areWindows 8 (released in 2012), Windows

7 (2009), and Windows Vista (2007).

•If you're buying a new computer or are

upgrading to a newer version of Windows, you

can choose from several different editions of

Windows, such as Home Premium,

Professional, and Ultimate.

•You may need to do some research to decide

which edition is right for you.

Linux

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Linux is a family of open-sourceoperating systems, which means they can be modified and distributed by anyone around the world.

This is different from proprietary software like Windows, which can only be modified by the company that owns it (Microsoft). T

he advantages of Linux are that it is free, and there are many different distributions—or versions—you can choose from.

Each distribution has a different look and feel, and the most popular ones include Ubuntu, Mint, and Fedora.

Operating systems for mobile devices

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Embedded Linux

Windows CE,

Pocket PC

Windows Embedded NT 4.0

Palm operating system

Protecting Your Computer

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A virus can run as an application, therefore it can:

Remotely access a computer, giving anyone complete control of the machine.

Run as a background process, using internet connection to send private data anywhere,

anytime.

Delete files, run programs, edit registry and steal information.

Corrupt Windows files to make a machine become unusable, causing it to crash and turn off

at any time.

Key log information such as passwords, usernames and credit card details.

Types of Viruses

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Boot Viruses

They attack the boot record, the master boot record, the File Allocation Table (FAT), and the partition table of a computer hard drive. They generally propagate from an infected diskette placed in the disk drive of a computer while it starts or otherwise. Joshi and Michelangelo are examples of boot sector viruses.

File Viruses (Trojan Horse)

They attack program files (e.g. .exe; .com; .sys, .drv; .ovl; .bin; .scr ) by attaching themselves to executable files. The virus waits in memory for users to run another program and use the event to infect and replicate. Trojan horse, also called RAT (remote access Trojan, or remote access trapdoor) is an example of a file virus.

Macro virus

This virus attacks applications that run macros, for example Microsoft word. The virus is activated when a document or a template file in which it is embedded, is opened by an application. Example: Melissa.

..

Types of Viruses

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Stealth Viruses

These viruses can disguise their actions and can be passive or active also.

The passive viruses can increase the file size yet present the size of the

original file, thus preventing detection. The active ones attack the

antivirus software rendering them useless. Example: Tequila.

Encrypted virus

This virus has inbuilt encryption software code which masks the viral

code making it difficult to identify and detect the virus.Example: Cascade

Types of Viruses

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Polymorphic Virus

Polymorphic virus has an inbuilt mechanism that can alter the virus signature. During the process of infection, it creates slightly modified and fully functional copies of itself. This is primarily done to elude the detection of a virus scanner as some are not able to identify different instances of an infection. One method it commonly uses to bypass a scanner involvesself-encryption performed with a variable key.Example: SMEG

Worms

A worm is an independent program that reproduces by copying itself from one system to another usually over a network. They infiltrate legitimate programs and alter or destroy data. Unlike other virus worms cannot replicate itself. Examples: SQL Slammer Worm, Melissa worm, Mydoom.

Sources of Viruses

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Storage devices: CDs, floppies, mobile disks

E-Mail

The Internet

Safeguarding against viruses:

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Antivirus

Antivirus software is used to prevent, detect, and remove

malware, including computer viruses, worms, and trojan horses. A

variety of strategies are typically employed by Antivirus software.

Signature-based detection involves searching for known patterns of

data within executable code. However, it is possible for a user to

be infected with new malware for which no signature exists yet.

Identify What You Can Do to Prevent a

Virus Attack

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The best cure for any virus is prevention. Viruses infect and damage unsuspecting computers, so it is vital to take preventive steps. To avoid virus infection, you need to do the following:

Develop a Virus Protection Plan

Install Antivirus and Data Integrity Software

Scan, Update, and Upgrade Automatically

Back Up Your Data Regularly

Consider Every Disk, Program, and Email Attachment as a Threat

Use Caution when You Download Files from the Internet

Be Aware of Virus Hoaxes

Educate Your Users

Identify How to Recognize and Remove a

Virus

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To recognize and remove a virus, you should be able to do the following:

List the symptoms of an infected computer.

The following are common symptoms of a computer infected with a virus:

The computer fails to start.

Programs will not launch or they fail when simple commands are performed.

Filenames change or become unreadable.

File contents change or are no longer accessible.

Unusual words or graphics appear on the screen.

Hard drives or disks are formatted.

variations occur in computer performance, such as slowdowns in loading or operation.

List the steps for removing a virus

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Follow these steps to contain and eliminate a virus:

Determine the type of virus

Isolate all infected systems and disks.

Make sure you have a clean disk formatted as a system disk.

Use the clean system disk to boot all systems with suspected infection.

Scan every physical and logical hard disk, as well as every disk.

Back up the necessary data and executable files to trusted, clean media.

Clean the infected standalone workstations

Clean the infected server.

Clean the disk

Some examples of Popular Antivirus:

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Norton Antivirus (Symantec)

McAfee Antivirus

Bit defender

Trend Micro

AVG

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Thank you