Re: [tlug] Bittorrent Newbie

["Stephen J. Turnbull" <stephen@example.com>]

>>>>> "Josh" == Josh Glover <jmglov@example.com> writes:

    Josh> This is a little unfair, in that you are leaving out one
    Josh> important part of Bittorrent's appeal

Not unfair at all, unless you think this is a Bittorrent advocacy
thread.  It's not, at least my posts aren't; it's a "why might Scott
Robbins observe consistently poorer transfer rates with torrents than
with FTP" thread.

    Josh> (and granted, the discussion has been mainly about pure
    Josh> bandwidth efficiency--whatever that means), which is the
    Josh> Share and Share Alike principle.

I find that appeal rather unappetizing, actually.  For example, SASA
really sucks for modem users and more than mildly so for ADSL users.
I dunno, maybe there are people with broadband who need to have SASA
enforced on them, but nobody I hang out with has that problem.

What _does_ need to be enforced is "no pig-piling on the server."  And
that's what bittorrent does well.

    Josh> Consider the TLUG tech meeting videos. Bittorrent is the
    Josh> perfect delivery vehicle, since we can a) avoid using OSDL
    Josh> bandwidth, and b) people who want the video are at least
    Josh> socially obligated to seed it for awhile once they have it.

Hmm.  I don't use bittorrent (I rarely download ISOs, although I admit
I did do Gentoo a couple days ago, but that's a separate message).  I
wonder how many seeds are out there at this minute?  I'm willing to
bet that in fact there's only one seed right now, which is OSDL, and
that very few of those who used torrents to get the videos even know
how to be a seed, let alone actually did it.  (At least the client I
looked at defaulted to shutting down rather than seeding when the
download was done, but that was back in the early days of bittorrent
when bandwidth was much more expensive than it is now.)

    Josh> And the fact that the Bittorrent protocol seems to at least
    Josh> suggest socially responsible behaviour makes me happy. :)

Well phrased.  I know how to successfully leech (at least off the
protocol described in Bram's paper, and in principle; I don't intend
to actually try it, at least not on somebody else's torrent).

Please note that SASA is not in general socially responsible behavior,
unless everybody's alike and all goods are highly substitutable.  It's
easy to cook up examples where SASA, taken literally, is pretty close
to the worst possible outcome.  In the case of Bittorrent, with a
group of peers with similar bandwidth and little bias toward
particular individuals always being first or always last, SASA is
an excellent heuristic.

-- 
School of Systems and Information Engineering http://turnbull.sk.tsukuba.ac.jp
University of Tsukuba                    Tennodai 1-1-1 Tsukuba 305-8573 JAPAN
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              ask what your business can "do for" free software.