/SECTION=file-spec
  /SECTION=LSE$SECTION (D)
  /NOSECTION

  Specifies whether LSE is  to  map  a  section  file  containing  DECTPU
  procedures,  key  definitions,  and  variables.   By  default, LSE maps
  section file LSE$SECTION.  If you specify another  file  specification,
  LSE  applies  the  default "SYS$LIBRARY:.TPU$SECTION" when it opens the
  file.

  If you specify /NOSECTION, LSE does not use a section file.