ietf-smtp
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Re: compressed content-transfer-encoding?

1999-07-28 13:23:46
On Wed, 28 Jul 1999 15:03:23 EDT, Keith Moore said:
it's been discussed many times; afaik the biggest problem is that nobody
has bothered to write up a concrete proposal.  the second biggest
problem,
of course, is that it would break lots of existing software.

That, and the fact that currently, the average text/plain being sent
around is relatively small (2-3K or so) and won't be a BIG win (you can't
save mor than 3 K, and that's only 2 packets on an ethernet ;)

The things that chew up the bandwidth are things like .GIF, .JPG,
etc attachements, which usually tend to have some compression already
done on them.  Now, if you have some big spreadsheets from some big
company that specializes in bloatware, perhaps the right thing to do
is convince them to make it take less disk space.  Yes, disk is cheap,
but that hardly justifies intentional waste....

Has anybody done any studies at all on whether said compression would
actually *win* us enough to be worth it?  As a data point, my MH folders
live on a compressed file system (each 4K block is LZ-compressed
individually),
and takes about 110M compressed and 198M uncompressed.  *HOWEVER*, a *very*
large chunk of that is Received: headers and the like, which would NOT
be compressible...


As you say, it is highly dependent upon the attachment type.   File types
that are already in a compressed state like JPEG's as you reference above
won't buy you anything.  On the other hand, at least in our environment, we
tend to send around a lot of documentation, in the form of Microsoft Word,
Adobe FrameMaker, or PDF formats, which compress rather nicely.   Images in
TIFF format are also highly compressible.  I would suspect that as the usage
of HTML in email increases, you might get some benefit here as well, but of
course only for the larger sized messages.

Due to the dependency on the attachment types, I suspect that what might be
a significant win for one environment would make no difference in another.
In reference to your comment above about the bloatware and convincing people
to use less space, I'm not sure what you have in mind here.  I'm not aware
of any simple way to have for instance your Excel, Word, or Frame files
automagically compressed.

Above you also mention the online storage of the messages.   What is the
intent here?   Are we trying to save in disk space or bandwidth utilization
when the attachment is in transit.   I was assuming the later.    Saving a
couple hundred meg of disk space with the price of drives these days hardly
seems worth the effort.

Best Regards,

Tim Kehres
International Messaging Associates
http://www.ima.com