ietf-nntp NNTP and 16-bit charsets

[Charles Lindsey]

In <ylwv7wecj6.fsf at windlord.stanford.edu> Russ Allbery <rra at stanford.edu> writes:

>Why not just say exactly what we mean?

>    NOTE: Texts using encodings (such as UTF-16 or UTF-32) that may
>    contain the NUL octet or the CR or LF octets in contexts other than
>    the CRLF line ending cannot be reliably conveyed in the above format.

OK, I now have that as the first paragraph of that NOTE.

>I believe that UTF-16 and UTF-32 are the correct things to reference, not
>UCS-2 or UCS-4, but someone who has a firmer grasp on the difference
>between a charset and an encoding may want to check me on that.

I see that Stan has confirmed that UTF-16 and UTF-32 are the correct ones
to refer to. But I would still like an explanation of what the subtle
difference between those terms is.

I see that RFC 2279 refers to UCS-2 and UCS-4. I presume also that UTF-16
and UTF-32 are ways of representing (or encoding, though the encoding is
trivial here) the 10646 charsets, such as UTF-8 is an encoding of those
charsets. So what are UCS-2 and UCS-4?

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