And pray tell, what header lines do you put at the beginning
of executable files?, database files?, and other files containing
inherently binary data?
Meta data (and codeset announcement is meta data) belongs in the inode
on Unix systems. Both the Mac and OS/2 treat such information
as meta data and put it in the file system, not in the file itself.
It is high time that Unix took one more step into the 20th century
before the 21st arrives. The fiction that all files are just byte
streams is just that, fiction. The user just has to know what files
are binary and what files are text (line oriented) files. Just try
the split command on an arbitrary file. If you are lucky it will find
NLs sufficiently often to not abend due to overflowing a static
buffer.
Just because this is a hard migration step for Unix does not mean that
we should not spec it out and start pushing for its inclusion in the
next POSIX release.
As for the SMTP mail headers, they are another example of wrong headed
thinking. They try to be all things to all people. The fundemental
problem is that they confuse the envelope with the letter. If we look
at an ordinary paper letter (and its envelope) we see that the
envelope only has routing information that is of interest to the post
office. These days it even has a bar code strip that I can't read but
I am sure the machine at the post office can. The envelope of
computer mail does not have to be human readable at all. It should be
compact and easily interpreted by the routers. Similarly the
"Received" lines should be on the envelope just like the post mark
cancelation, not in the letter. This does not mean that I as a
recipient should not be able to look at the envelope. But I should
not have to see it if I don't want to. Yeah, I know a fancy mail
reader can suppress the junk headers, but simple programs should be
simple. Incidentally, BITNET (aka RSCS) gets this separation right.
The envelope is the CP TAG information and is entirely separate
from the contents of the letter. So much so that it has always
been 8 bit clean because mail is just a file and sent by the
same mechanism that sends binary files.