Re: Communicator Unicode

From: John Gardiner Myers (
Date: Tue Sep 16 1997 - 13:27:12 EDT

> Does the IANA currently discriminate between _character set_ and _content
> transfer encoding_ in a way similar as MIME does?

You're getting definitions mixed up, which is actually not surprising
given all the subtleties.

MIME does not itself use a concept of a "coded character set". What
both MIME and IANA refer to as a "character set" (more unambiguously
referred to as a "charset") is actually a combination of a "coded
character set" and a "character encoding scheme". See RFC 2130,
particularly section 0 and appendix C for more details.

A "content transfer encoding" (what RFC 2130 calls a "transfer encoding
syntax") is an entirely different beast.

> It will be very helpful to have different tags for the character set itself
> and the transformation format. Otherwise you end up in a product
> (ISO-10646 version) * (transformation-format) of different character sets
> to be registered -- clearly an uneconomical approach.

MIME quite deliberately ignored the concept of a "coded character set"
absent a "character encoding scheme" as not being useful for

Current thinking is that labeling the ISO 10646 version is harmful.
Including it greatly increases the chance that something will be
unreadable because the reader does not recognize the label. If Unicode
and ISO 10646 do their jobs properly, then the version information is
not useful.

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