Incremental backup of a file

Thnaks,
    But my requirement is quite difference. I want to built incremental backup system. That system will store some data from client to server over internet. So bandwidth is a major and great matter, for that I will try to transfer very minimum data. So when litte change made in a file then i will try to send only that changed portion of file. For that I must find out which part has been changed, then i will transfer these changed byte data, keep in mind file may any type like text, image, songs, data base backup type or any. So we can't send whole file after relaising that file has been changed (for checking is file has been changed, we can save last access time and and can compair with that time) .
    So if you have any alternative idea please share with me.
Thanks,
Suman Biswas
See my blog on C# Socket

Hi,

When you find modified file you can simply replace old file with new one :)

Thanks,
           But by that way how I can get modified bytes of that file? Also how I can marge modified bytes with original bytes?
              In that position Diff Algo helps, but it can help little because for 33% change it gives 100%(approx.) modified bytes. So it does not help my requirement well. So if you/any one have any altertnative idea please inform.
Thanks,
Suman Biswas
See my socket, C-sharp blogs.

Hi,

You can implement a simple logic for this. Just keep track of the modified date and time of the files you upload or taken backup. You can keep it in database against each file path or name. When next time user goes for taking backup just compare this modified date and time for each file which is already backed  up and if modified date and time is newer than file in your backup then take a backup of this file or keep the original one as it is.

Mahesh