Rmail, Gnus, POP, and IMAP

Wed, 02 Mar 2016 05:34:05 +0100

Rmail is a mail-reader which you can hook to your
mailbox by means of the POP or IMAP protocols (Post
Office Protocol and Internet Message Access Protocol).

It is an Emacs interface to using those protocols and
a mail server, and then having the result
organized on screen.

You can also use Rmail as an interface to send mails -
you can use the data displayed by Rmail to populate
a message buffer, and then send it. But the message
mode is actually Gnus!

RMS, big-time mail writer and Rmail user, said about
it that:

    Rmail is the primary Emacs mail-reader. I don't
    know how many people currently use it, but I will
    ignore any suggestion to treat it as unimportant.

For sure, no one is saying Rmail is unimportant but
compared to Gnus it is very primitive even if you
don't consider everything else that comes with Gnus
that doesn't come with Rmail.

For example Rmail stores every mail in a single file
(named RMAIL by default). This makes it a pain doing
anything with it with common shell tools. It is very
un-Unixy - which isn't a matter of principle, but an
obstacle whenever dealing with it.

So Gnus is, apart from everything else it does which
is a lot, a much more powerful mail-reader than Rmail.

RMS' word "primary" is debatable as well as both Gnus
and Rmail comes with Emacs out-of-the-box.

Rmail should not be confused with the shell tool rmail
which has to do with ancient UUCP technology.

The POPs including POP3 are 80s protocols on the
TCP/IP stack that fetch mail batch-style, by default
deleting them on the mail server when done downloading
them to the disk.

Compared to IMAP, POP is much simpler which is why it
is still around. IMAP supports simultaneous
connections to a mailbox, and also a mail directory
structure which POP doesn't.

IMAP can also do stuff to the material on the server
while POP basically gets the data and then deletes it
(on the server).

Any questions?


PS. When Lumumba was campaigning in Congo he always
    ended his speeches with that question. There were
    never any questions, because if they were, the
    person who asked was beaten up after the meeting
    was concluded.

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