chunker

from The Free On-line Dictionary of Computing (8 July 2008)

chunker
dechunker
split

   <programming> 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)