Source : Free On-Line Dictionary of Computing

chunker
     
         A program like {Unix}'s "split" which breaks an
        input file into parts, usually of a pre-set size, e.g. the
        maximum size that can fit on a {floppy}.  The parts can then
        be assembled with a {dechunker}, which is usually just the
        chunker in a different mode.
     
        (1998-12-15)