ConCat/Split provides facilities to split and re-join large files.
The split facility lets you break a file into commonly used disk sized (or custom sized) chunks. It automatically names each file section in a convenient manner so that it's easy to re-join them.
The concatenate facility lets you join 2 or more files into a single file. It's the Windows equivalent of the copy command.
Note: The concatenate facility will only join split files. It will not intelligently join separate structured files such as audio, video, or word processor documents.