Windows Operating System - 2

Windows Desktop

        Desktop just like a physical top of a desk, the Windows desktop is where you put the things you are working on or went to access. They are appearing on the monitor hence, the full appearance calls desktop. The desktop is the main screen in Windows (or any other operating system) where you can put icons that act as shortcuts to various programs.

• Icon

        An icon in Windows is a small picture or object that represents a file program, web page, or commands. Most of the time, the icon picture relates to the function of the item that it represents.

        For example, if the icon is attached to an e-mail program, it might be a picture of a letter. Icons are located on the desktop, in the start menu, and various other places.

• Shortcut

       A shortcut is a Windows icon that when clicked does something - starts a program, views a graphic, plays a sound, etc. Since they are only "paths" to the program, they can be deleted without deleting the actual program itself. On your desktop, you probably have several shortcuts.

• Recycle Bin

      When you delete a file, Windows XP will place the file into the recycle bin instead of deleting altogether; this allows you to restore the file in case you deleted it by mistake. For example say you deleted a file by accident you could double click on the recycle bin icon to see its contents, and then restore the file back to where you deleted it from by right clicking on it and then selecting restore from the menu that appears.

Keeping the Desktop tidy

      The more you use Windows XP the more your desktop may start to fill up with icons, either because you install more software or you create your own icons.

      Windows XP can automatically align and sort your desktop icons to keep the desktop tidy, to achieve this click the right mouse button anywhere on the desktop and a menu will appear, hover the mouse pointer over Arrange Icons By and a sub menu will appear, from here you can sort your desktop icons be Name, Size, Type, Last Modified date.

       Selecting the Auto Arrange option will automatically align your desktop icons every time you add one to the desktop.

       The Desktop Cleanup Wizard will remove any desktop shortcuts that have never been used to a new folder on your desktop called Unused Desktop Shortcuts.

 

Windows Operating System - 1 | Using the Mouse

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Windows Operating System - 1

Using the Mouse

A mouse is a hand - held device that controls the movement of a pointer on your screen. You use your mouse to perfome tasks on your computer.

As you move the mouse, a mouse pointer moves on your screen. When you position the pointer over an object, you can press (click pr double click) the mouse button to perform different action on the object. The pointer usually appears as an arrow, but it can change shape. The following sections explain the other actions you can perform with your mouse.

Mouse Functions

• Click - To select something on-screen., click the left button quickly and lightly - whatever you are pointing to when you click appears high lighted to show that it's selected.

• Double-Click - To activate an object on-screen, click twice in rapid succession. Click - Click will manipulate the object usually resulting in the opening of a specific program.

• Drag - To move or size an object on-screen, hold down the mouse button while you move the mouse across the mouse pad. Dragging moves the object to a new location. Dragging a border or frame changes the size of the object.

• Right-Click - Displays special menus. When you right-click, you see a menu of commands related to the icon or area of the screen that you are pointing to.

• Wheel Button - Some mice have a third button or wheel button. The Wheel Button allows you to scroll from screen to screen in a multiple screen document. It also allows you to move to a certain location in the document quickly by moving the mouse button, similar to dragging the navigation bar on a web page.

Windows Operating System - 2 | Windows Desktop

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Types of Operating Systems

           Operating system can be broadly classified into two categories based on the type of interface provided to the user.

Command Line Interface

         In these types of operating systems the user can enter commands through the keyboard and each command will perform a specific action. But this type of interface is very difficult for a beginner to use, because the commands have to be remembered.

          MS-DOS is such a Operating System. Dos stands for Disk Operating system. It was developed by Microsoft as an operating system in the 1980s. Windows 3x needed DOS to run, but the later versions of Windows do not.

Graphical User Interface

         These operating systems provide the user the ability to manipulate the computer in a more interactive way. These systems are more user-friendly and easier to use than command driven interface, because the commands need not be learnt.

E.g. Windows, MacOS, Linux

Windows 7

MacOS

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Operating System

         An Operating System or OS is a software program that enables the computer hardware to communicate and operate with the computer software. Without an Operating System, a computer would be useless.

Features Expected of an Operating System

• To Startup and Shutdown the computer. 

• To act as an interface between the user and the hardware.

• To perform house keeping tasks such as file handling, disk/ memory management.

• To be able to allow the user to configure the system. This includes changing the types of printers, adding new hardware (such as sound cards), etc.

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The Internet

   The Internet is a network of autonomous computer networks that spans the globe. It provides an infrastructure for global electronic information exchange. Today the Internet is used by millions of people of facilitate various activities such as business, education and plain communication.

   The Internet grew out of a United States Department of Defense project, the ARPANET (Advanced Research Project Agency Network) started in late 1960s. Its main objective was to provide network links between universities, research organizations and remote computer centers.

            The following figure shows how the Internet is structured. At the bottom level are the organizations and home uses connected to the Internet. Typically users connect to the Internet through local Internet Service Providers (ISPs). The ISPs are in turn connected to the Internet Backbone through regional networks. Typically ISPs lease high-bandwidth lines that connect into the Internet and rent that bandwidth to Internet users.

             Typically a home user (client) connects to the Internet via telephone lines. If the telephone network is analog a modem is needed in between the computer and the telephone line to convert digital signals generated by the comuter to analog signals that are being transmitted by the telephone network.

              When a client registers with an ISP for Internet usage he will get an account. To access the Internet by using this account, the client has to dial the ISP and log on to this account.

             On the Internet information is available mainly through three mediums: the World Wide Web (WWW), Usenet News (News) and Electronic Mail (e-mail). The WWW is built on top of the Internet. It can be viewed as a large notice board with posters and printed notices stuck to it. On the WWW Web servers provide information on the Internet. A user can access the information by using a web browser.

• To Connect to the Internet, your dialer software calls an access number.

• Your modem converts the signals from your computer to signals that travel over wire lines to an Internet service provider (IPS).

• Your IPS provides the connection to the Internet.

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How to Protect a Computer from Computer Viruses

        There are many ways of preventing a computer from virus attack. Some of these precautions are listed below.

• Verbal Warning
• Avoiding the use of unchecked disks
• Avoiding the use of unauthorized or unchecked software

Anti-virus Software

        Anti-virus software contains anti-virus scanners, which look for viruses.

• On-access scanners - Automatically check the hard disk and diskette each time the system starts up.

• On-demand scanners - Executes only on users demand and can be scheduled to run at various times

       Most commercial anti-virus software provides both types of scanners. It will take some time for an anti-virus software designer get to know about a new type of virus and to write software to detect it. Therefore anti-virus software gets out of date very often.

Firewalls

        A computer generally has many ports (think of them as doorways), which allow external programs to access the computer. Hackers use programs to automatically detect vulnerabilities in the computer and gain access to the computer by using this weak access points. Firewall protection secures these ports so malicious programs can sneak into your machine. Firewall software can also be used to check whether files downloaded from the internet follow a defined security protocol and free of viruses.

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Main Types of Virus

Boot Virus

          Boot virus infects the boot sector of the hard disk and is activated every time the computer is switched on. Once infected, the computer may fail to start properly. Usually boot viruses spread from the boot sectors in floppy diskettes to the boot sector of the hard disk. When you start up the system with an infected diskette in the diskette drive, the virus transfers from the diskette to the boot sector of the hard disk. Once infected, the virus may remain in the main memory and infect other diskettes.

File Virus (Parasitic Virus)

         File viruses are virus programs attached to executable files. They become active every time the program is executed.

Macro Virus

         A macro is a collection of application specific instructions coded to automate some manual process such as formatting a word document. Macro Viruses are either complete macros or macro segments embedded as parts of legitimate macros. They may come straight from the software manufacturer's original disks. Once a computer is infected with a macro virus the following action may result.

• Unusual messages
• Unknown macros listed in macros list
• Save data in unintended formats
• Lost data

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Main Phases of Virus Activity

The main phases of virus generally follows are;

• Gains access to the system

• Lies dormant

• Propagates

• Virus is triggered by some event

• Virus Action

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