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

    Opens the file for writing. The following restrictions apply to
    the /WRITE qualifier:

    o  Use the /WRITE qualifier to open and create a new, sequential
       file. If the file specification on an OPEN/WRITE command does
       not include a file version number, and if a file with the
       specified file name and file type already exists, a new file
       with a version number one greater than the existing file is
       created.

    o  Use the /READ qualifier with the /WRITE qualifier to open
       an existing file. When the file is opened, the pointer is
       positioned to the beginning of the file. (This differs from
       OPEN/APPEND, which positions the pointer at the end of the
       file.) You cannot use OPEN/READ/WRITE to create a new file.

    o  The /WRITE and the /APPEND qualifiers are mutually exclusive.