This idea has been superseded by the ideas described at (p3,mrc)
The diode directory is a mutable object that between mutations provides a mapping of a name onto a 32 bit number. Additions and deletions may be made to a diode directory. A name is just what a record collection thinks a name is. A diode directory comes with a hole-free factory that produces an associated object that maps a name to its 32 bit value.
The above solution requires a dd reader for each combination of compartment and sub directory. Thus 1000000 dd readers are potentially required. UGH! It is not even clear when to create them.