Re: SFTP File open modes

[Albert Lunde <Albert-Lunde%northwestern.edu@localhost>]

> How many well-known and often utilized ways of encoding ASCII text files
> are there (answer: two)? Is an ASCII mode as you suggest likely to be
> useful? Or do we want a mode for UTF-8 and UTF-16, EBCEDIC, and so on?
>
> Perhaps it would be best to add an operation by which the client can ask
> the server for a given file's content type and encoding. The server's
> response should indicate whether it knows, whether it knows for certain
> and, if it knows at all, what the content type is.
>
> All encoding conversions though should be left to the client though.

* First, one should distingush between a literal _ASCII_ mode, and a
_text_ mode.

The most specific proposal posted suggested using Latin-1 as a
least-common-denominator wire encoding, with a bunch of negotiated
alternatives. In this day and age, I think it would make more sense
to use something like UTF-8 (further spectified to reduce ambiguties).

I count at least three widely-used ways of encoding end-of-lines with
characters (CR,LF, CRLF) plus fixed-length records, plus counted
varable-length records: I don't know what you are thinking of in
saying "two".

* Text mode is a big win in the case of an OS which has files in some
well-known but ideosyncratic format, because the clients don't have
to say, know all the varients of EBCDIC or VMS record formats, just a
single wire format.

* But I think you've got a point that a server may not _know_ the
encoding of files, or may not want to support the overhead of a text
mode.

I don't know any foolproof way to detect which files in my Mac are in
Mac-extended-ASCII, which are in Latin1, and which are in Shift-JIS
(because I've been running the Japaneses language kit on on of my
Macs for years). The Mac type/creator scheme is more or less
orthogonal to i18n issues.

So this isn't something we should expect to be able to implement on
every server, or for every file.
--
    Albert Lunde         Albert-Lunde%northwestern.edu@localhost (new address)
                         Albert-Lunde%nwu.edu@localhost (old address)