synchronisation of folders and clients

Source file sync question
http://social.msdn.microsoft.com/Forums/nb/synctoy/thread/e55d4af2-e228-4846-a690-44f10d5144b6
SyncToy is a free tool which helps you copy, move, rename, and delete files between folders and computers quickly. At the core of SyncToy is Sync Services for File System which is a component of the Microsoft Sync Framework (freely available on Windows platforms). The Microsoft Sync Framework was built to enable synchronization of any data source including Files.   

 Ultimately you can think of SyncToy as a nice UI wrapper built on top of Sync Services for File Systems.

If you download a copy of the latest Microsoft Sync Framework, you will find a number of file synchronization samples that will enable you to build a solution very similar to that of SyncToy.  Not surpisingly, the samples function very similar to the way that SyncToy does.  Within these samples you can modify them however you like.  Whether that is to synchronize files with a Web Site (such as Flickr or SmugMug) or over a network (including Bluetooth, or WiFi).

If you are interested in learning more or if you have any questions.  Please visit our Sync Developer Center and our Sync Forum.

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http://www.tgrmn.com/web/file_synchronization.htm

File Synchronization is the process of making sure that two or more locations contain the same up-to-date information. If you add, change, or delete a file from one location, the synchronization process will add, change, or delete the same file from the other location.

ViceVersa software lets you synchronize files and folders between Laptops, Desktops, File Servers, Hard Disks, USB disk drives, NAS, etc, over LAN, WAN, VPN, USB connection. Learn more... You can run ViceVersa on-demand, at scheduled times or continuously, while monitoring files for changes.

ViceVersa is easy to use. Select source and target folders and click the "Compare" button. ViceVersa will show you which files are matched, unmatched, newer or older. You can then decide how to synchronize to make sure that all your computers and storage media have the latest files and data.

File Synchronization Benefits: Working at home, on the road, in satellite offices, working on different computers, it's hard for to keep current with the latest files and data. Documents, spreadsheets, databases and sales, contact information, all can be revised many times a day. With ViceVersa, your data can be automatically synchronized between computers and any kind of disk device including USB hard disks, floppy, Zip, Jaz, NAS and optical drives or to the network LAN, VPN. Learn more...
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File Sync Between Desktop and PDA
You could use SyncToy 2.0 to sync files between your desktop and PDA. It's a free UI application to sync files between two endpoints mapped onto the host running SyncToy (desktop in your case). It uses Sync Framework's File Sync Provider component underneath.
Or else, you could use File Sync Provider in you C# application to sync files.
Good place to start would be here :
Want to build your own File Sync tool: http://social.msdn.microsoft.com/Forums/en-US/synctoy/thread/e55d4af2-e228-4846-a690-44f10d5144b6
and this one:
http://msdn.microsoft.com/en-us/library/bb902860.aspx

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http://www.codeplex.com/FileSynchronizer1
http://www.gegereka.com/?query=As%20Fast%20File%20Sync%20For
TwinCAT-Project-Sync-FileAccess.zip:Connect this storage
Video_sync.pdf Connect this storage
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As Virtual Machine Dedicate Virtual NIC
One NIC for internet connection.
One NIC for dedicated virtual NIC for virtual machine.
This could reduce CPU utilization a little for NIC.
Install Procedure:
a. Install Virtual PC.
b. WIN + R | ncpa.cpl (Network connection)
c. Choose the NIC which dedicated NIC for virtual machine

d. Run Virtual PC  
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As Fast File Sync for NB and Desktop 
One NIC for internet connection.
One NIC for private LAN for file sync.
Most NB has wireless LAN and ethernet LAN. If you always use wireless LAN for internet connection, you could use ethernet LAN for file sync.
Install Procedure:
a. WIN + R | ncpa.cpl (Network connection)
b. Choose the NIC which want to use for file sync with NB.



c. You also need to modify file sync setting on Windows Vista