i want to develop a simple download manager..i have seen download managers downloading a file..but they have multiple download points
e.g. suppose i have a file like this on a web server

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download points :   1          2          3             4              5

they are downloading from all the points 1,2,3,4,5 simultaneously..i'm not able to figure out how they do that...does anybody has an idea??? it'd be of great help

Depending on the server that file is hosted on, you can request the file size, and whether the server supports resume. If it does, then you can use the HTTP Range header to specify which block of data you want.