RFC 385 (rfc385) - Page 4 of 8

Comments on the File Transfer Protocol

NWG/RFC 385 Page 2


           ASCII with ASA vertical format Control - This is the
                    "Print file-ASCII" defined in RFC 354.  The
                    server is to transform the data in accordance
                    with ASA (Fortran) vertical format control
                    procedures for printing on printers that
                    still use this standard.  The data is to be
                    transferred as 8-bit bytes.

           EBCDIC with ASA vertical format control - This is the
                    EBCDIC Print File defined in RFC 354.  The
                    server is to transform the data in accordance
                    with ASA (Fortran) vertical format control
                    standards but using the EBCDIC character code.
                    The data is to be transferred in 8-bit bytes.

      The new types are to be denoted by symbols E for EBCDIC, P
      for Print file-ASCII and F for Formatted (ASA standard)
      EBCDIC print file.  A discussion of the ASA vertical format
      control appears in NWG/RFC 189, Appendix C, and in
      Communications of the ACM, Vol 7, No. 10, p. 606, October
      1964.  According to the ASA vertical format control
      standards, the first character of a formatted record is not
      printed but determines vertical spacing as follows:

           Character    Vertical Spacing before printing
           ---------    --------------------------------
            Blank          One line
              0            Two lines
              1            To first line of next page
              +            No advance

      In addition to the above four, there are more characters
      (defined in Appendix C, RFC 189) which represent an IBM
      extension to the ASA standard.

   4. A comparison of "stream" and "text" modes is in order.  The
      advantages of "stream" mode are:
           1) The receiver need not scan the incoming bytes.
           2) It is usable with all data types.

      The disadvantages are:
           1) The EOF by closing the connection is not reliable.

           2) The EOR by ASCII _CRLF_ is unreliable as the _CRLF_
              really may be valid data rather than an EOR.  It is
              an EOR only if the sender and receiver have a _prior_
              agreement to that effect.