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

1 - /ERROR

       /ERROR=label

    Transfers control on an I/O error to the location specified by
    label (in a command procedure). If no error routine is specified
    and an error occurs during the writing of the file, the current
    ON condition action is taken. The /ERROR qualifier overrides any
    ON condition action specified. If an error occurs and control
    passes successfully to the target label, the reserved global
    symbol $STATUS retains the error code.

2 - /SYMBOL

    Causes the expression to be interpreted and its expanded value
    placed in a 2048-byte (instead of a 1024-byte) buffer before
    the write operation is performed. If you specify multiple
    expressions, their values are concatenated and placed in the
    2048-byte buffer. Use the /SYMBOL qualifier to write a very large
    record.

    Each expression specified must be a symbol. You cannot specify
    character string expressions (that is, strings in quotation
    marks) with the /SYMBOL qualifier.

    If you do not use the /SYMBOL qualifier, the entire command,
    including the expression or expressions, is placed in a 1024-byte
    buffer.

3 - /UPDATE

    Replaces the last record read with the record specified with the
    expression parameter. You must be able to read and write to a
    file to use the /UPDATE qualifier. Use the WRITE/UPDATE command
    only after a READ command. The WRITE/UPDATE command modifies the
    last record you have read.

    With sequential files, you must replace a record with another
    record of the same size when you use the WRITE/UPDATE command.