% Part 2: Content-Type header
% There ought to be a few iso character set standards defined.
% ISO 8859-1 and ISO 10646.
% And MAILASCII, ISO 8859-1 and ISO 10646 should be the recommended
% types for text bodies.
US-ASCII should be the default type for messages. No other
recommendations need be made since anything else will be labelled as
to how the characters are encoded and the MUA and mail gateways can
then handle them appropriately.
The commonly used character set encodings need unique defined types
so that mail gateways can make appropriate translations. A mail
gateway needs to know how the bits map to glyphs so that it can make
appropriate translations (EBCDIC <--> ISO 8859-1, for example).
For this reason, I would urge that ALL of the ISO 8859-N character
set standards be formally supported by the RFC (including only ISO
8859-1 is a kind of European parochialism). Also, EBCDIC should be
included as a predefined type (There are such machines on the Internet
running TCP/IP, SMTP, & friends). Eventually we will need to also
support 16bit and 32bit character sets as well (UNICODE is 16bit and
DIS 10646 is 32bit).
It seems to me that marking text as TeX or Troff source is a
secondary consideration and not one that a mail gateway should have to
be aware of or handle specially. To make it a consideration that has
to be handled by a mail gateway makes it harder to implement a mail
gateway that will work correctly and interoperate cleanly.
Randall Atkinson
randall(_at_)Virginia(_dot_)EDU