NAME
       GetUnitID - find out what type of disk is out there

   SYNOPSIS
       idtype = GetUnitID( unitNum ), DRResource
	D0	            D0         A6

	LONG GetUnitID(LONG);

   FUNCTION
	Gets the drive ID for a given unit.  Note that this value may
	change if someone calls ReadUnitID, and the drive id changes.

   INPUTS
	unitNum -- a legal unit number (zero through three)

   RESULTS
	idtype -- the type of the disk drive.  Standard types are
		defined in the resource include file.

   EXCEPTIONS

   SEE ALSO
	ReadUnitID()

   BUGS