RFC 448 (rfc448) - Page 1 of 3


Print files in FTP



Alternative Format: Original Text Document



NETWORK WORKING GROUP                                  R.T. Braden
REQUEST FOR COMMENT NO. 448                            UCLA/CCN
NIC #13299                                             February 27, 1973
UPDATES: RFC 354, 385, 454


                           PRINT FILES IN FTP


INTRODUCTION
------------

    Many of those who contributed to the definition of the FTP and RJE
protocols have expressed varying degrees of uncertainty or unhappiness
with the "print file" type in FTP.  This RFC is intended to review the
problem of print files in preparation for the forthcoming FTP meeting.
Originally drafted on the basis of RFC 385, this RFC has been updated to
reflect the terminology of the latest FTP document 454.  (Changing the
terminology doesn't solve the problem!)

    It turns out that the Network RJE protocol as presently defined (see
NIC 12112) seems to force a particular interpretation of print files in
FTP and in fact, this interpretation is probably different from the one
assumed by most FTP implementors.

VERTICAL FORMAT CONTROL
-----------------------

    What is a print file?  Presumably it is a file which is intended to
be sent (eventually) to a printer process to create a hard copy.  Many
operating systems (particularly those which are batch-processing
oriented) allow the programmer to include control codes within a file to
be printed, to control the vertical format of the printed page--for
example, single/double line spacing, overprinting, and page ejection.  A
"print file" is one which includes such vertical format control ("VFC")
information.  There are three common ways for printer processes to
determine VFC:

CASE N:  Non-Print File
         --------------
         The file contains no VFC information.  The printer process
         applies a standard format (e.g., single space, standard
         vertical margins) if the file is printed.

CASE T:  Print File with ASCII Format Effectors
         --------------------------------------
         The file is "Telnet-like", containing the ASCII controls CR,
         LF, and FF to provide VFC.



Braden