RFC 520 (rfc520) - Page 1 of 8
Memo to FTP group: Proposal for File Access Protocol
Alternative Format: Original Text Document
Network Working Group J. Day
Request for Comments: 520 Center for Advanced Computation
NIC: 16819 25 June 1973
A Proposed File Access Protocol Specification
Attached is a proposal for the File Access Protocol. FAP is an
extension to FTP. I believe the specification is fairly general and
should provide a good jumping-off place. I hope the protocol is
specified in such a way as to fit with idiosyncrasies of most
systems. If the protocol would cause an inordinate amount of burden
on your system for one reason or another I would like to hear about
it.
At some later date when the difficulties of implementation are better
known, I would like to see several levels of implementation specified
and implementation be done in terms of those levels.
From rumors I have heard I believe this will also allow creation and
transfer of what TENEX calls "holey" files. But, I am not sure of
all of the implications of that, or what would happen (or should
happen) when a "holey" file is moved to a site that doesn't really
have such a thing, per se. Comments from the TENEX crowd would be
appreciated.
I think some further work could be done to make FAP easier for record
oriented systems. This would probably require an extra command or
parameter to specify all operations are in terms of records.
Comments are invited.
In the long run though, I would like to see FAP thrown away. The
commands as they are described merely add a finer structure to the
present RETR, STOR, and APPE without much additional overhead. The
sequence:
OPEN R FOO.BAR CRLF
READ ALL CRLF
CLOS CRLF
is equivalent to RETR FOO.BAR CRLF. FAP could be merged with FTP to
give a much richer, coherent whole.
In writing this document, I ran into the deficiency of reply codes
for protocols. Three digits is no where near enough. I would like
to suggest that as another interim solution we go to a five digit
Day