r read access, close a DLA file, and extract comments from a DLA
   file's comment area.
<P>
 
   In the Fortran and C SPICE Toolkits, DAS functions can open an existing
   DLA file for write access and delete or write to a DLA file's comment
   area.
<P>
 
   In the Fortran SPICE Toolkit, DLA functions are provided to open a new
   DLA file and to start and finish new DLA segments. DAS functions are
   provided to write data to DLA segments, read data from DLA segments, and
   update data in existing DLA s