What is Network?

A network or communication network is a system of interconnected communication devices that can communicate with one another and share information. Therefore computer network can be defined as:

A system in which more than one computers or large number of computers are interconnected together, communicate freely with one another and share information is called computer network.

A network can be internal to an organization or span the world by connecting itself to the internet. In computer network, network operating system is used that controls and co-ordinates the activities of computers that are connected to the network. The example of these operating systems are: windows NT, UNIX, and Novell etc.

Types of Network

Networks are of three types. These are:

• Local Area Network (LAN)
• Wide Area Network (WAN)
• Metropolitan Area Network (MAN)

Local Area Network

A local area network is a network system in which computers are interconnected in a limited geographical area, such as network of computers in college computer laboratory or network of computers in office building etc.

Wide Area Network

A wide area network is a network system that covers a large geographical area such as different cities of country or different countries of the world. In WAN telephone lines, satellites, microwave, fiber optic etc. are used as transmission media.

Metropolitan Area Network

A Metropolitan area Network is a network system that covers area of a single city. Usually, MAN connects more than one LANS in a city or town and covers a smaller geographical area than a WAN. The cable television, telephone companies or local corporations use MAN.

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How to access the sharing data offline? NEW

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If you have deleted files from your hard drive, don't panic! Using the right unerase software deleted files can be recovered very easily. Success is more or less guaranteed as long as you act as soon as you realize that the files are missing.

Even if your files have been overwritten or corrupted, if the disk they were stored on has been formatted or repartitioned, or if you don't know how they were lost, it's still likely that you can recover them. To find out more about data recovery read How To: Data Recovery. If you have lost files from CD or DVD, see How To: CD Data Recovery. But if you only want to know how to recover deleted files, just read on!

Recommended undelete software

For Windows users:

• Use Uneraser.

For Apple Mac users:

• Use Data Rescue II.

When a file is deleted from your computer, it is not really deleted. It is simply removed from the directory of files in the folder.

If you're using Windows and you deleted the file using Windows Explorer, the file will not have been erased from the disk. It will have been moved to the Recycle Bin. If you're a Mac user, it's moved to the Trash. If you use Linux KDE, it's the Wastebin. Whatever the bucket shaped object is called, as long as a file remains there it can easily be restored in its entirety, with no problem at all. So the first thing to do when you want to recover a deleted file is look in the Recycle Bin / Trash / Wastebin.

If the file you need isn't there - if you emptied the bin, used Shift Delete to get rid of the file, deleted it from within an application or used some other method of removing it that bypassed the bin - then don't despair. It's almost certainly recoverable. When you empty the Recycle Bin or delete a file using another method, the file is still not really deleted. The file no longer exists as far as the operating system is concerned, and the space it occupied becomes available for re-use by other files. But the disk space does not get re-used straight away, so the data contained in the deleted file will stay on your hard drive for some time to come.

A frequent misconception is that the System Restore feature of Windows Millennium, Windows XP and Windows Vista can be used to recover deleted files. However, it is no help at all. System Restore was developed specifically to restore system files back to an earlier state. Its purpose is to enable easy recovery when a software update, installation or removal has an adverse effect on the system. It provides a simple way to roll things back to a point in time when everything worked.

Think about it. It would be very annoying if, when you used System Restore to get your computer back to the state it was in a few days ago, it removed all the letters, emails and other documents you'd received or created since then as well. So System Restore ignores file types associated with office documents, photo images, music files and other things that are of interest to you. It doesn't back them up in a Restore Point, so it can't restore them.

Chances of recovery

Because the operating system doesn't immediately re-use space from deleted files, a file can be recovered or undeleted right after it has gone, and for a fair while afterwards. But the chances of a perfect undelete decrease the longer you leave it, because eventually some or all of that space will be re-used.

The chances of recovery also depend on how full your computer's hard drive is. Windows tries to avoid re-using disk space that has recently been freed, to give deleted file recovery software a better chance of working. But the fuller a drive is is, the sooner the freed-up space is going to be used by other files.

If you have defragmented the hard drive since the file was deleted, then this has severely harmed the chances of a successful recovery. Current files will have been moved into the free space left by deleted files in order to reduce fragmentation, making it much less likely that undelete software will be able to find anything useful.

Recover deleted files

Tools that can help you undelete files are not provided as standard in any operating system. So you will need to use undelete software.

Undelete software understands the internals of the system used to store files on a disk (the file system), and uses this knowledge to locate the disk space that was occupied by a deleted file. As we've already said, because another file may have used some or all of this disk space, there is no guarantee that a deleted file can be recovered. But usually it is successful. In fact, Uneraser users have often been amazed to find that it recovers files that were deleted months or even years ago. The best undelete programs give you an indication of the chances of recovering a file intact, and even provide file viewers so you can check the contents before recovery.

If you're running Microsoft Windows we consider that DiskInternals Uneraser is one of the best undelete software products available. Uneraser has powerful tools to help locate lost data among the thousands of files on a hard drive. It also has the widest range of built-in viewers to let you examine the files it finds before recovery. There is a free trial version so you can see for yourself whether it can recover the files you lost. If a file looks perfect in the viewer then recovery is pretty well 100% guaranteed. See a tutorial showing how to recover deleted files using Uneraser.

For Apple Mac users we recommend Data Rescue II. The standard version is installed on your Mac, but if you need to you can obtain an .dmg file to create a boot CD that allows you to run the software from that. Again, there's a free demo, so you can see if it will get your files back before paying for it.

Recovering files from your main drive

One of the cardinal rules of data recovery is that you must stop using the disk that contains the files you want to recover as soon as you realize they are lost. This is because anything that gets written to the drive could potentially be written to the space that was holding the data you hope to recover. If the files you lost are on your computer's main or only drive (normally the C: drive in Windows) then using the computer at all is inadvisable, because even if you avoid writing to that drive, Windows will still be doing so.

You can avoid this potential problem by running data recovery software from a boot CD. The DiskInternals data recovery boot CD builds a Windows based recovery CD using the Windows installation files found on most PCs (for the benefit of technical types, it uses BartPE.) This allows you to run Uneraser and other DiskInternals data recovery tools under a familiar Windows interface. Alternatively, you can use Data Rescue PC, which comes ready to burn to CD (you can also order a ready to use CD through the post at extra cost.)

If it seems like too much work to create a bootable data recovery CD then of course you can always take a chance on installing software such as Uneraser on your main hard drive. If you have a large drive and most of it is unused then there may be only a small possibility that the software installation will overwrite your data. It's your data, so the decision is up to you, but don't say we didn't warn you!

Saving the recovered data

Because it is bad practise to write to the drive that contains the deleted data, you should save the files that have been recovered to a different drive to the one they were recovered from. This could be an external drive or a network share, even a USB memory stick. The Uneraser product recommended here has the ability to burn files direct to writeable CD or DVD without creating any temporary files on the hard drive. It even allows you to save the files to an FTP server.

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Your computer have important information that don't want other person to see it? Do you feel there always have someone looking at the data in your computer?

Nowadays, There have more than 70% of people in the world using computers. People don't save their data on paper anymore, they use their computer to save all the data, like company documents, photos, files, chatting history...etc... But do you know the data in your computer are watching by someone else? Your information may be already in someone's hand.. I am going to introduce some basic ways to protect your computer from the Hackers.

1. Using Anti virus software Remember to use Anti virus software to search your computer every week, and turn on the Anti virus software every time you turn on your computer. That can helps stop unauthorized access on your computer, prevents virus infection, and "cloaks" your data ports against a hacker scanning for openings.

2. Be careful Email Attachment Never open or download the attachment in your Email, unless you know what is it for , or you know the person that sent to you. There have chance that virus is hiding inside the attachment.

3. Be careful what you download in the internet You have to be careful what you download in the internet. There have a lot of program can spy on your computer after you download. Those program can get the information from your computer, the information when you searching on the internet back to the creator of the program. It is a big deal actually, why? Because when you and searching on the internet, there have some important information will pass out (Like your Credit card number, or your social security number). You do not want to give out those information. There have some ways that you can protect your computer from those spy, one of them are the anti-spyware Program, it can protect your personal information from being taken without your permission.

4. Make sure your computer OS and softwares are up to date Hackers are always looking for the security Gaps to hack into someone's computer. The first things they look for are the operating system, web browser and software that install in your computer. So make sure everything in your computer are up to date.

5. set up a password for your Wireless Network Make sure you set up a password on your wireless router. A lot of wireless router are set to no password require when you first install it. Be sure you do that, at least set up a basic security on your wireless network, or else everyone can access to the computers in that Wireless Network.

Those are the basic tips to protect your computer from the hackers. There also have many others advance ways to stop the hackers, but at least do the things that I mention above first. Then you can get into more advance ways to protect your computer. Hope this information will help some of you.

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Use your pen drive as a temporary ram in vista

Till this date, Microsoft’s windows had Page File (A virtual memory file, stored on hard disk) options for the memory requirement of the computer, so that the computing can be done at cheaper rates and that too without installing the physical memory (RAM).

The page file is used by the Windows OS to cater the needs of various applications when the physical memory is fully used up. The reason for that is, that Virtual memory is slower as compared to the physical memory and thus Phyical memory takes the first priority.

However, with the release of Windows Vista, Microsoft has introduced a new technology called ReadyBoost. With the help of this technology one can use any Flash drive, SD Cards, CF Cards as the third memory option for the computer.

Now, the benefits of Flash Drive or Cards as a source of Memory :

1. It is faster than the virtual memory which is accessed through the hard disk drive.
2. It is cheaper as compared to the actually Physical Memory.

How can it be activated ?

In order to activate the ReadyBoost technology on your FlashDrive or Memory Cards, you have to follow these steps…

1. Open My Computer.
2. Right Click on the Removable Disk Drive and select Properties.
3. Click on ReadyBoost Tab.
4. Enable the feature by selecting the option and allocate the amount of space you want to use as memory.

Things to be noted….
1. Regardless of the fact that you use Readyboost or not, you need at least 512 Mb of memory to run Windows Vista decently.
2. If your device is not giving the option of ReadyBoost then it means that it doesn’t clear up the minimum data trasfer rate required by ReadBoost technology.

Hope this is useful..

credits:D@nGeR™

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It's not always wise to upgrade your hardware every time you feel your computer is getting slow. In fact, Microsoft's operating systems slow down a PC when you have lots of programs installed. In this tutorial I will tell you some easy tricks to get most out of your hardware.

1. Disable extra startup programs

Several items add up to the start up list when you install different software. Such programs are loaded when your system boots and remain in memory (RAM), they also continuously use processor. Here are is what you have to do to make them go away:

• Goto Start>Run
• Type "msconfig", without quotations
• Hit enter key or click the OK button
• A window will show up, you have to click the startup tab, as shown in the figure
• In the Startup tab you will see several boxes and some of them will selected (checked). All you have to do is to uncheck extra items that are of no use. If you run an antivirus program it is not recommended to uncheck it.
• After making you choices press the OK button, you will be prompted to restart computer to apply changes.
• After restarting your computer a dialogue will be displayed. You can check the option for not showing this dialogue every time your PC reboots.

2. Disable Extra Services

On menu opened by msconfig command, there is also another tab for Services. Click it and check "Hide All Microsoft Services" option. This option will display you list of third party services. Uncheck the services that are undesirable. As usual you have to reboot to apply the changes.

3. Adjust Display Settings

XP has a very cool looking user interface, but it consumes a certain amount of memory. To make it a little lightweight you have to:

• Right click My Computer and select Properties
• Click the Advanced tab
• Go to Performance>Settings (have to click settings button in the performance section)
• Uncheck all except:
  Use visual styles on windows and buttons
  Use drop shadows for icons labels on the desktop
  Show translucent selection rectangle
  Show shadows under mouse pointer
  Show shadows under menus
• Finally click Apply and OK

4. Remove Widgets and Background

Different third party widgets and visual styles like for Vista like look and feel make your system slow. If you remove such packages you system will perform better on CPU and memory intensive tasks. Selecting default and no wallpaper as background also gives better performance than that of "high quality" wallpapers.

5. Folder Browsing

When you try to browse folder, Windows automatically searches for printer and network files. This is a performance overhead. To fix this you have to follow following steps:

• Open My Computer
• Click Tools>Folder Options
• Select the View tab and unselect the check box for Automatically search for network folders and printers
• Click Apply then OK and finally reboot to apply the change.

6. Indexing Service

Windows XP comes with a very heavy and not so good "Indexing Service". The service "claims" to makes indexes of different files on your computer so that they can be retrieved easily. The service consumes a large amount of memory, and it has no major advantage either. To disable it you have to:

• Go to Start>Control Panel
• Double click Add or Remove programs.
• Select Add/Remove Windows Components, a new dialogue, as shown in the figure, will appear.
• Uncheck the Indexing Service, if not already unchecked
• Click Next to finalize

7. Size of Page File

Page file size is not constant by default. Due to this operating system has to resize the file each time when more space is required, this is a performance overhead. All you have to do is to set the file size to a reasonable limit. Follow the steps:

• Right click My Computer, Select Properties then Advanced tab
• Click the settings button under the performance section
• Click the Advanced tab
• Click Change button under the Virtual memory section
• "Virtual Memory" dialogue will appear (also shown in the figure below)
• Highlight the drive containing page file, which is C: by default
• Select the Custom size radio button and give same values in Initial size and Maximum size fields.
• Click Set and OK buttons to apply the changes

If your system has a sufficiently large memory (1 or 2 GB) then you can even disable paging.

8. Enable Direct Memory Access (DMA)

Go to:

• Right Click My Computer, select properties
• Select the Hardware tab
• Click the Device Manager button
• Double click IDE/ATAPI controllers
• Keep on checking if DMA is enabled for each, you have to double click each option click Advanced Settings tab (as shown in figure) The tab may or may not be available for each option. It is only available in Primary and Secondary Channels.
• Set the transfer mode to "DMA if Available" both for Device 1 and 0
• Perform the same operation for other items in the list, if applicable.

Note: All of these techniques may not be available to you depending on you access rights on the system. Contact your system administrator in this regard.

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In this tip I will tell you a quick way to open a built-in Windows XP Applications by using “Run box”. The run option of Start menu is used to run a program or to open a document directly. If you do not know the exact location of the program or document then click on Start button to open Run and type the programs shortcut name to open it directly, For Example when you will open “Notepad” application and type “notepad” at the “Run box” then press “Enter” to run it. In this way you can run a lot of Windows XP Applications and Utilities.

Executable Filename Function

Access.cpl Used to run Add/Remove wizard

Accwiz.exe Runs the Accessibility Wizard

appwiz.cpl Runs the new add or remove programs wizard

wab.exe Runs the Windows Address Book

ntbackup.exe Runs the Windows backup program

charmap.exe Runs the Windows Character Map

Control.exe Runs the Control Panel

Timedate.cpl Launches the computer’s date and time panel

Devmgmt.msc Runs the Device Manager settings

Cleanmgr.exe Lets you play the Disk Cleanup utility

netstat.exe View information about network settings

hdwwiz.cpl Run the new hardware search wizard

Chkdsk.exe Runs the utility that checks your hard disk problems

cmd.exe or command.exe Both use to run MSDOS commands

Defrag.exe Run the Disk Defragmenter, which organizing files on your hard disk

Desk.cpl Launches the Display properties dialog box

fxsclnt.exe Use to Runs the Fax Console panel

control.exe folders Display the Folder option dialog box

control.exe fonts Display the Fonts Folder option dialog box

freecell.exe Runs the FreeCell game

joy.cpl Runs the Game Controllers dialog box

mshearts.exe Launches the Hearts game

helpctr.exe Display the windows Help and Support Center

hypertrm.exe Runs the HyperTerminal application

bckgzm.exe Run the Internet Backgammon game

chkrzm.exe Run the Internet Checkers game

iexplore.exe Run the Internet Explorer

inetcpl.cpl Run the Internet Properties dialog box

main.cpl Help you to manage the Keyboard Properties

logoff.exe Shortcut to Logoff Windows XP

magnify.exe Launches a program to magnify windows applications

conf.exe Runs the Microsoft NetMeeting conferencing program.

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