/sys$common/syshlp/helplib.hlb FORTRAN, /I4  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  /[NO]I4                         D=/I4

  Controls how the compiler interprets INTEGER and LOGICAL
  declarations that do not specify a length.

  This qualifier can also be specified on the OPTIONS statement.  The
  default is /I4, which directs the compiler to interpret INTEGER and
  LOGICAL declarations as INTEGER*4 and LOGICAL*4.  If you specify
  /NOI4, the compiler interprets them as INTEGER*2 and LOGICAL*2,
  respectively.