Controls the allocation of unpacked enumerated  data  types  and
  Boolean  data  types,  which  are considered to be an enumerated
  type  containing  two  elements.   Note  that   specifying   the
  ENUMERATION_SIZE  attribute  overrides  any value you previously
  specified with this qulaifier.

  You can specify the following values for keyword:

     BYTE
       Allocates unpacked enumerated data types with fewer than 255
       elements in a 8-bit byte. Otherwise, the enumerated type is
       allocated in a 16-bit word.  Default on OpenVMS VAX systems.

     LONG
       Allocates all unpacked enumerated types in a 32-bit longword.
       Default on OpenVMS Alpha and OpenVMS I64 systems.