TENEX FTP PROBLEM
A warning about Tenex FTP sending the wrong line-ending character.
Braden, R., "TENEX FTP PROBLEM", RFC 571, DOI 10.17487/RFC0571, November 1973, <https://www.rfc-editor.org/info/rfc571>.
@misc{rfc571,
series = {Request for Comments},
number = 571,
howpublished = {RFC 571},
publisher = {RFC Editor},
doi = {10.17487/RFC0571},
url = {https://www.rfc-editor.org/info/rfc571},
author = {R. Braden},
title = {{TENEX FTP PROBLEM}},
pagetotal = 1,
year = 1973,
month = nov,
} RFC text
Network Working Group Robert T. Braden
Request for Comments: 571 UCLA/CCN
NIC #18974 November 15, 1973
TENEX FTP PROBLEM
Tenex users of FTP should beware of a problem in the current Tenex
implementation which is likely to cause incorrect results when
transferring files to a non-Tenex site. Some Tenex programs create
an ASCII US (Unit Separator) character as an end-of-line indicator,
instead of CR LF. The current Tenex FTP user implementation passes
these US characters over the Network instead of translating them to
CR LF as required by FTP protocol. If the recipient is not a Tenex,
he will not do anything special with these US characters and the line
spacing will be lost. In the case of sending to CCN, we will treat it
as a very long logical record and fold it into successive 360
records.
A circumvention is to pass the Tenex file through some Tenex program
that does the necessary conversion before sending it over the
Network. We know that TECO will remove US's; there are probably
other means. Loading and saving the file with TECO will replace all
US's with CR LF sequences.
[ This RFC was put into machine readable form for entry ]
[ into the online RFC archives by Katsunori Tanaka 4/99 ]
ISO Plain Language
On this page
§1The Tenex Line-Ending Problem
Some Tenex programs used the ASCII Unit Separator character to mark the end of a line instead of carriage return and line feed. The Tenex FTP user implementation sent Unit Separator characters over the network rather than translating them as the FTP protocol required.
A non-Tenex recipient would not treat these characters as line endings. The RFC gives the example that CCN would treat the file as one very long logical record and fold it into successive 360 records.
Some Tenex files ended lines with a character that other systems did not treat as a line break. Tenex FTP sent that character without converting it, so the recipient could lose the file's line structure.
§2Converting the File Before Transfer
The RFC suggests passing the file through a Tenex program that performs the needed conversion before sending it. It specifically names TECO: loading and saving the file with TECO replaces Unit Separator characters with carriage-return and line-feed sequences. The author notes that other means may also exist.
Before sending the file, use a Tenex program to replace its line-ending characters. The RFC says that loading and saving it with TECO makes this conversion.
§3Who Is Affected
The warning concerns transfers from Tenex to a site that does not give special meaning to Unit Separator. The problem is the sender's failure to translate the local line-ending representation into the FTP form, not a claim that every Tenex file or transfer is affected.
The issue applies when a file contains these Tenex line endings and goes to a system that does not recognize them. Converting the file first avoids relying on the receiver to interpret the Tenex character.