VMS Help FORTRAN, /CONVERT, IBM  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Specifies that numeric data in unformatted files is in big endian
  integer data of the appropriate size (INTEGER*1, INTEGER*2, or
  INTEGER*4) and IBM System\370 floating-point data of size REAL*4 or
  COMPLEX*8 (IBM short 4) and size REAL*8 or COMPLEX*16 (IBM long 8).
  REAL*16 data is not converted.