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Re: [PLUG] OT: Comparing POP3 and IMAP
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Perhaps we should directly state the differences, nobody has done it,
because we all assume everybody knows them, but just in case:
In the beginning... if you used a computer, it was probably a server
or a dumb terminal. If it had internet access, it was probably on a
static IP at a college or government location. Each system had users, and
users could have email. If your address was: Bob@trick-or-treat.nsa.gov,
it meant you had an account called "bob" on the server "trick-or-treat" in
the domain nsa.gov. If you sent an email to sue@trick-or-treat.nsa.gov,
the server would simply move your message to her mail spool. More likely
than not, you were directly using the server via telnet or some similar
protocol, or maybe running an X program on the server, but displaying it
on a remote workstation. If you sent an email to sue@hot-male.com, then
your server would send the mail to that server (actually, the MX for that
domain, but I digress), and then when sue logged in, she could check her
email.
Only, with the advent of PCs that weren't connected all the time, and
didn't have static IPs, and that were powerfull enough to run GUI programs
locally, it became more and more common to want to read your email on a
machine that it wasn't delivered to. To solve this, POP, and
(later?) IMAP were invented.
POP is based on the idea of copying/moving the mail spool that is on the
server to your computer. The idea here is you dial up, get the mail off
you ISP's unix box, copy it to your PC, and probably delete it. You like
it because you have all your mail locally, and your ISP likes it because
you free up space for them. Obviously data downloaded with POP is
available for off-line access.
IMAP is more or less the opposite, it is a way to access you mail from
other machines. This model is based more on centralized access, rather
than just pumping everything down to your PC. It has the advantage that
you could have 5 different PCs accessing your email via IMAP, and still
use PINE or an X program from the server to access the same
email. Off-line access seems to depend on the client (some cache the IMAP
data, and I have seen some that don't seem to at all). As mentioned
before, typically clients will scan [and download] the message headers so
that you can get a listing of all of the mail on the server, but without
actually downloading the full body of all of it. When the user attempts
to read or preview a specific message, the full message is downloaded and
displayed. As such, there is often a slight delay when changing messages,
especially on dial-up connections, but there is rarely a 10 minute wait to
download all of your email at once when you connect.
for my use, I have mainly used (in the past 5 years or so):
a.) PINE (local)
b.) PINE (IMAP)
c.) Netscape/Mozilla (IMAP)
d.) Ximian Evolution (IMAP)
I have also almost always been doing this in on-line mode, so for the
clients that support disconnected mode, you might want to check how they
handle what they do with IMAP messages (i.e.. is there a way to tell it to
retrieve the full body of all messages before going off-line?)
(Note: Anyone, please feel free to jump in and add more info or correct me
if I mis-stated something).
-- noah silva
On Mon, 22 Apr 2002, Art Alexion wrote:
> I was thinking of replying the same way, but decided thay your topic was
> your topic. Paul is right, though. Actual speed -- which can be
> affected by many things other than your protocol -- is one of the least
> significant reasons to choose between POP and IMAP. Paul did a good job
> listing the more significant reasons. I'd recomment your paper focus on
> those reasons.
>
> Paul wrote:
>
> >
> >
> > What is more important to a user, the actual time or the perception of time?
> >
> > IMAP seams faster if, for the moment, you choose not to read every
> > message that comes in. The message headers download very fast. Only
> > the selected messages download completely. So, if you are on a slow
> > link and don't want to download that message with a 5Meg attachment,
> > you can skip or delete it quickly. If you want to run through all
> > messages quickly, then POP seams faster.
> >
> > So, the actual time is not really a concern for me. The perceived
> > time is, dependent on my reading style. There are more important
> > features of IMAP which make it superior to POP. The ability to check
> > mail from multiple computers without having local mailboxes getting
> > out of sync. The benefit of not losing mail if the client computer
> > crashes since the mail is kept on the server which is also backed up.
> > Maybe more secure.
> >
> > From the server side, I think POP is better since the messages are
> > removed from the server when they are viewed. But, actually, drive
> > space is pretty cheap, so it might not matter.
> >
> > Given a choice, I would always choose IMAP. As far as the actual
> > statistics of sending and recieving, I don't know and it really
> > doesn't matter to me.
> >
> >
> >
> > Bradley Molnar wrote:
> >
> >> Hi all-
> >>
> >> for a class project, I am supposed to compare pop3 and IMAP. We are
> >> supposed to compare anything we can find out about them. I was planning on
> >> comparing speeds of sending/retrieving e-mail and how long it takes, throw
> >> in a bit of statistics, etc.
> >>
> >> What I wanted to ask the group was this -- how would you go about comparing
> >> the two protocals. Would you use a regular client and a stopwatch
> >> (which is
> >> currently the fall-back plan), or, is there a mail client that can be
> >> configured to use both pop3 and imap that has a self timing system.
> >>
> >> thanks for your time and advice
> >> -brad
> >>
> _____________________________
>
> art alexion
> mailto:arthur@alexion.com
>
> ______________________________________________________________________
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>
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