Why is file concatenation on Windows so slow?
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I am working on a small utility app to concatenate large video files. The main concatenation step is to run something like this on the command line on Windows 7:

    copy /b file1.dv + file2.dv + file3.dv output.dv

The input files are large - typically 7-15Gb each. I know that I am dealing with a lot of data here, but the binary concatenation takes a very long time - for a total of around 40Gb of data, it can almost an hour.

Considering that the process is basically just a scan through each file and copying it's contents to a new file, why is the binary copy so slow?