RFC 141 UNKNOWN FILE TRANSFER · PROTOCOL DESIGN · FEEDBACK

Comments on RFC 114: A File Transfer Protocol

Rand's comments on file access, commands, status, and errors in RFC 114.

On rfc-editor.org ↗
PUBLISHED
April 1971
AUTHORS
E. Harslem, J.F. Heafner
STREAM
Legacy
BUILDS ON
RFC 114 — FTP
COMMENTS
9
OPERATING SYSTEM MENTIONED
IBM OS/360
DOI
10.17487/RFC0141

RFC text

Original text · RFC Editor View on rfc-editor.org ↗
Network Working Group                                      E. F. Harslem
Request for Comments: 141                                  J. F. Haefner
NIC 6726                                                            Rand
                                                           29 April 1971

             COMMENTS ON RFC 141 (A FILE TRANSFER PROTOCOL)

   1.  A file transfer protocol is needed.  Bushan's proposal would
   satisfy a particular current need that we have, as well as short-term
   envisioned needs.

   2.  Bushan's protocol would apear to be straight-forward in
   implementation, and extensible as claimed.

   3.  We would like to see implementations of such protocol be
   accomplished such that the file transfer program has general and
   complete access to the local file storage.  That is, it should be
   able to access a file that it did not create.  For example, if a
   program or user creates a file at site X (completely independent of
   the file transfer program), it would then be desirable to be able to
   retrieve the file via the file transfer program.  This is not a
   requirement of RFC #114 but we would like to see it implemented where
   possible.

   4.  Since implementation of a subset of transaction types is
   specifically permitted, we suggest inclusion of the following
   commands (in addition to append).

      insert records     within a file
      delete records     from within a file
      replace records    within a file

   Although these operations are not directly supported under IBM
   OS/360, we have used them with a non-standard file subsystem under
   IBM OS/360 and find them quite useful.

   5.  In addition to retrieve and lookup, get names of files under my
   access control would be useful.

   6.  The absence of status requests and responses is apparent.
   Although this is typically a function associated with a remote job
   entry (RJE) system, since the execute request is present it would
   seem appropriate to inquire about the status of the process created
   by the execute command.  This becomes increasingly more important
   where the execute is implemented as an RJE-like operation and
   scheduling time of the job might be prolonged.

   7.  When requesting execute, the using host sends parameters upon
   receipt of the rr response.  Executing a task can be implemented in
   several ways.  The options our 360 affords are RJE at job level and
   the attach macro.  Our preference would be the attach macro which
   immediately initiates an independent OS task within the partition of
   the program issuing the attach (presumably the File Service).  Such a
   task normally receives parameters upon initiation and can thereafter
   receive parameters from a program via some mechanism such as an event
   control block.  The second method requires special modifications to
   the program being executed; hence, it is not desirable.  Therefore,
   we either need the parameters included in the execute command or will
   not actually start execution until parameters are received.

   8.  Upon abnormal termination, one should include part or all of the
   spurious request as well as an identify- ing code to facilitate
   precise error recognition.

   9.  We would be interested in the outcome of the MIT/ Harvard
   experiments with the RFC #114 protocol.  What were the pitfalls,
   etc.?



         [ This RFC was put into machine readable form for entry ]
          [ into the online RFC archives by Simone Demmel 4/97 ]

ISO Plain Language

On this page
PROBLEMThe file-transfer proposal in RFC 114 needed review from sites considering implementation.
MECHANISMHarslem and Haefner support the proposal and suggest broader file access, record commands, file-name listings, status replies, and more informative error responses.
THE COMMENTSRFC 141 updates RFC 114 with review comments and questions; it is not a replacement specification.

§1Support and File Access

Harslem and Haefner say a file-transfer protocol is needed and consider Bhushan's proposal straightforward to implement and extensible.

They would like file-transfer programs to access files that they did not create, where possible. They also suggest commands to insert, delete, and replace records and a way to list files under the user's access control.

The authors support the proposal and want programs to reach existing files, edit records, and list accessible files.

§2Status and Execution Requests

The authors note that the proposal has no status requests or responses. Because it includes an execute request, they suggest being able to ask about the status of a process it creates, especially if execution waits for scheduling.

For an execute operation, they discuss when parameters should be sent to the remote system. They prefer an approach that starts an independent task and suggest including parameters in the execute command or delaying execution until the parameters arrive.

If a remote system starts a job, the requester should be able to ask about its status. The authors also discuss how to provide the job's parameters before it starts.

§3Reporting Errors and Sharing Results

For abnormal termination, the authors suggest including part or all of the request that failed along with an identifying code. This would help users recognize the error more precisely.

They also ask for reports on the MIT and Harvard experiments with RFC 114, including any pitfalls discovered. RFC 141 itself does not give those results.

An error reply should include information that identifies the failed request. The authors also ask early testers to share the problems they found.

§4References