parameter l_bin_identifier = 4,		!length of binary identifier
     +          l_project = 8,			!project (account) in ASCII
     +		l_blocks = 4,			!disk block size (I*4)
     +		l_overhead = 10 		!LIB$TREE header overhead

      parameter l_key =				!length of tree key
     +		l_bin_identifier+l_project

      parameter l_data_struct =			!length of data structure
     +		l_bin_identifier+l_project+
     +		l_blocks

      parameter l_node_size = 			!VM space per node
     +		l_data_struct+l_overhead
c
      structure /data_struct/
	union
	  map
	    integer*4 bin_identifier
	    character*(l_project) project
	  end map
	  map
	    byte key(l_key)
	  end map
	end union
	integer*4 blocks
      end structure
c
      structure /node_struct/
	byte header(l_overhead)
	union
	  map
	    integer*4 bin_identifier
	    character*(l_project) project
	  end map
	  map
	    byte key(l_key)
	  end map
	end union
	integer*4 blocks
      end structure