FDL

   File Definition Language (FDL) files define the attributes of 
   RMS files. You can use FDL to specify RMS options and parameters 
   that can be used when creating a file. If you use the callable 
   FDL routines in a program, you can specify most RMS run-time 
   options used when opening (or creating) a file and connecting a 
   record stream.

   Although you can use FDL with sequential and relative RMS files, 
   it is especially useful for defining RMS indexed files. Key 
   definitions, area definitions, placement options, and bucket-size 
   settings are typical of the information used to define indexed files 
   that have optimal run-time performance.

   The following DCL commands invoke utilities that use FDL files:

      ANALYZE/RMS_FILE, CONVERT, CONVERT/RECLAIM, CREATE/FDL, EDIT/FDL

   Refer to the Guide to OpenVMS File Applications and the OpenVMS
   Record Management Utilities Reference Manual for information
   on FDL and the utilities that use FDL. See the OpenVMS Utility
   Routines Manual for information on the routines that use FDL
   files.