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

  /[NO]CONVERT=option        D=/CONVERT=NATIVE

  Specifies a nonnative numeric format for unformatted data.

  By default, an unformatted file containing numeric data is assumed
  to be in the little endian floating-point or integer format used
  for memory representation (/CONVERT=NATIVE or /NOCONVERT).

  There are other ways to specify numeric format for unformatted
  files:  you can specify a VMS logical name, OPEN (CONVERT=) or
  OPTIONS/CONVERT.  The order of precedence is VMS logical name, OPEN
  (CONVERT=), OPTIONS/CONVERT, and then compiler option /CONVERT.
  The /CONVERT compiler option and OPTIONS/CONVERT affect all unit
  numbers used by the program, while logical names and OPEN
  (CONVERT=) affect specific unit numbers.

  The /CONVERT compiler option specifies a default data-conversion
  type for all logical units opened in the program unit, either
  explicitly by an OPEN statement or implicitly by a READ, WRITE or
  other I/O statement (with the exception of DEFINE FILE).  You can
  override the default data-conversion type by specifying the
  CONVERT= keyword in the OPEN statement or by defining a logical
  name of the form FOR$CONVERTnnn, where "nnn" is the logical unit
  number (including leading zeros if necessary).

  For more information on using unformatted data files, using VMS
  logical names to specify CONVERT options, and information about the
  ranges of the various data types, see your user manual.

1 - BIG_ENDIAN

  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 IEEE floating-point data of the appropriate size and
  type (REAL*4, REAL*8, COMPLEX*8, or COMPLEX*16).

  INTEGER*1 data is the same for little endian and big endian.

2 - CRAY

  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 CRAY floating-point data of size REAL*8 or
  COMPLEX*16.  REAL*4, REAL*16, and COMPLEX*8 data is not converted.

3 - FDX

  Specifies that numeric data in unformatted files is in little
  endian integer data of the appropriate size (INTEGER*1, INTEGER*2,
  or INTEGER*4), VAX F_floating for REAL*4 and COMPLEX*8, VAX
  D_floating for REAL*8 and COMPLEX*16, and little-endian IEEE
  X_floating for REAL*16.

4 - FGX

  Specifies that numeric data in unformatted files is in little
  endian integer data of the appropriate size (INTEGER*1, INTEGER*2,
  or INTEGER*4), VAX F_floating for REAL*4 and COMPLEX*8, VAX
  G_floating for REAL*8 and COMPLEX*16, and little-endian IEEE
  X_floating for REAL*16.

5 - IBM

  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.

6 - LITTLE_ENDIAN

  Specifies that numeric data in unformatted files is in little
  endian integer data of the appropriate size (INTEGER*1, INTEGER*2,
  or INTEGER*4) and IEEE floating-point data of the appropriate size
  and type (REAL*4, REAL*8, REAL*16, COMPLEX*8, or COMPLEX*16).

  INTEGER*1 data is the same for little endian and big endian.

7 - NATIVE

  Specifies that format for numeric data in unformatted files is
  determined by the floating-point format representation in memory;
  no conversion is performed.

  This is the default.

8 - VAXD

  Specifies that numeric data in unformatted files is in little
  endian integer data of the appropriate size (INTEGER*1, INTEGER*2,
  or INTEGER*4) and Compaq VAX floating-point data of format
  F_floating for size REAL*4 or COMPLEX*8, and D_floating for size
  REAL*8 or COMPLEX*16, and H_floating for REAL*16.

9 - VAXG

  Specifies that numeric data in unformatted files is in little
  endian integer data of the appropriate size (INTEGER*1, INTEGER*2,
  or INTEGER*4) and Compaq VAX floating-point data of format
  F_floating for size REAL*4 or COMPLEX*8, and G_floating for size
  REAL*8 or COMPLEX*16, and H_floating for REAL*16.