VMS Help DTM, RECORD, Qualifiers, /APPEND  *Conan The Librarian (sorry for the slow response - running on an old VAX)

   Continues recording the specified test after the end of the input
   file is reached. The /APPEND qualifier applies to interactive
   terminal tests only.

   If you specify an input file using the /INPUT qualifier, Digital Test
   Manager records using input from the input file. When the end
   of the input file is reached, this qualifier enables you to
   record further; if you do not specify this qualifier, recording is
   terminated when the end of the input file is reached.