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

  A[w] (Character Editing)

  If the corresponding I/O list element has a character data type,
  character data is transmitted.  If it has any other data type,
  Hollerith data is transmitted.  The value of "w" must be less than
  or equal to 32767.

  On input, transfers "w" characters or Hollerith values from the
  external record and assigns them to the corresponding list element.
  If the input value contains fewer characters than "w", it is padded
  on the right with blanks.  If the input value contains excessive
  characters, it is truncated on the left.

  If the variable is numeric, the ASCII value of each character is
  placed in each byte of the variable, starting at the low-order
  byte.

  On output, transfers the contents of the corresponding I/O list
  element to an external field "w" characters long.  If the output
  value contains fewer characters than "w", it is padded on the left
  with blanks.  If the output value contains excess characters, it is
  truncated on the right (for numbers, the high-order bytes are
  lost).

  If the output value is numeric or untyped, the ASCII value of each
  byte of the variable, starting at the low-order byte, is
  transferred to the record.

  The "w" can be omitted and defaults to the number of characters in
  the character variable or the number of bytes in the numeric
  variable.