 ADDR  | Base DAS d.p. address
   +---------------+
   | DP COMP SIZE  | Size of d.p. segment component
   +---------------+
   | BASE CHR ADDR | Base DAS character address
   +---------------+
   | CHR COMP SIZE | Size of character segment component
   +---------------+
 
</PRE>
   The ``base address'' of a segment component of a given data type is the
   address, in the DAS address space of that type, preceding the first
   element of that component. All DAS addresses are 1-based.
<P>
 
   The general for