RFC 448 (rfc448) - Page 2 of 3

Print files in FTP

RFC 448                    PRINT FILES IN FTP              February 1973


CASE A:  Print File with ASA (Fortran) VFC
         ---------------------------------
         The first character of each record is a VFC code; see RFC 454
         for the codes.

    Assuming there are to be print files in FTP, these _three_ cases
need to be considered.  These three cases are explicitly included within
the RJE protocol as "transmission" modes; we have borrowed the RJE
labels N,T, and A from NIC #12112.  The current FTP (RFC 454) seems to
provide only _two_ cases: _unformatted_ and _print_file_.  It is unclear
from RFC 454 how these two FTP formats are related to the three VFC
cases.  For example, it is unclear whether the FTP format is meant to be
a property of the file as transferred over the Network or of the file as
stored by the server.

    As I understand it, the Tenex system supports only case T.  The
distinction between Case N and Case T is not always clear, however.  If
a Tenex file which contains only the CR LF combination of format
effectors is printed, it may be considered Case N where CR LF delimits a
logical record, and where the standard format is to begin printing each
record on a new line.  The RJE protocol uses this ambiguity to
advantage; see below.

    The IBM operating systems, on the other hand, support Cases N and A.
The "output writer" process which drives the printer must know whether
or not a file to be printed contains ASA VFC, so the system
distinguishes internally between "print files" (Case A) and non-print
files (Case N).  The "print file" attribute is normally attached to a
print file when it is created.  For example, the language processors
typically create print files for their "printer" output streams.

    Hence, when CCN's server FTP executes a STOR command, it must decide
whether or not the new file is to be marked with the internal print file
attribute.  As noted earlier, FTP does not explicitly distinguish the
three possible cases.  We must either add some additional assumptions or
server-dependent information outside FTP, or we must add a new format to
FTP.

IMPLICATIONS OF RJE
-------------------

To send an output ("printer") file to a user host, the RJE server will
cause his FTP user process to send the file with the following
attributes*:


*Note:  Making the obvious conversion from RFC 385 to RFC 454
terminology.



Braden