# URLs -- the ftp case

Fred Swartz (fred.swartz@umich.edu)
Wed, 27 Oct 1993 15:54:08 -0400

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    Message-Id: <9310271954.AA04238@merit.edu>

    To: uri@bunyip.com

    From: "Fred Swartz" <fred.swartz@umich.edu>

    Subject: URLs -- the ftp case

    Date: Wed, 27 Oct 1993 15:54:08 -0400

In the case of ftp, the URL as specified does NOT allow the retrieval
of files since the text/binary mode can not be determined. This
difference may not be important for those of you who use only one kind
of system (eg Unix), but the representation of text files differs on
Unix, DOS, and the Macintosh. The transfer mode must be known to make
intersystem transfers work correctly.

There is a certain air of unreality in the ftp URL description
in that it reads as though everything is fine, and only in the
last paragraph brings up the fact that the URL as specified really
doesn't work. As a practical matter it does mention that you can
make guesses by looking at the file name and the data, but you
will never know for sure.

Instead of giving the false impression that URLs work for ftp, perhaps
the mode, as with Gopher, could be added. This is a very distant
cousin of "type" in that it really indicates the transfer mode, not
the object type. In other words, postscript, rtf, ... files are
all transfered in text mode, even though you may think of them as
having different types.

One way to indicate these two transfer modes might be to have alternate
protocol identifiers: ftpt and ftpb (for text and binary).

-- Fred (fred.swartz@merit.edu)

PS: although I prefer the idea of file types, I'm proposing transfer
mode as a less contentious, albeit weaker, alternative.

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