[vox-tech] bittorrent - no seeds but distributed copies increase

[Peter Jay Salzman]

On Mon 26 Jul 04,  3:32 PM, Ken Bloom <kabloom at ucdavis.edu> said:
> On Mon, Jul 26, 2004 at 02:46:48PM -0700, Peter Jay Salzman wrote:
> > On Mon 26 Jul 04,  2:37 PM, Samuel N. Merritt <spam at andcheese.org> said:
> > > On Mon, Jul 26, 2004 at 02:08:22PM -0700, Peter Jay Salzman wrote:
> > > > Question:
> > > > 
> > > > How does the "distributed copies" get larger when there are no seeds?
> > > 
> > > I think that "distributed copies" measures how many complete copies of
> > > the file you could get if you took all the pieces that everyone has and
> > > assembled them. 
> > > 
> > > For example, consider a five-part file.
> > > Alice has: 1 2 3 4
> > > Bob has:       3 4 5 
> > > Carol has: 1 2   4 
> > > 
> > > You could make one complete copy of the file from all this, so there'd
> > > be 1 distributed copy. If Carol got piece 5 from Bob, then you could
> > > assemble two complete copies. 
> > > 
> > > That's the integer part of distributed copies; I'm not sure where the
> > > fractional part comes from. Maybe it's the size of the largest
> > > distributed incomplete subfile divided by size of file, but that's just
> > > a shot in the dark. 
> >   
> > ok.  this was my understanding.
> > 
> > > > Does the tracker ever inject packets into the torrent when needed (like
> > > > when seeds == 0 and distributed copies < 1.0)?
> > > 
> > > No. The tracker doesn't have a local copy of the file. If there are no
> > > seeds and < 1 distributed copy, everyone's download will stall before
> > > finishing 
> > 
> > this was also my understanding.  but my question still stands: how does
> > the distributed copies increase if there are no seeds?
> > 
> > i'm looking at a bittorrent right now.  it's remained constant at:
> > 
> >    seeds: 0 seen now, plus 0.983 distributed copies
> >    peers: 19 seen now, 98.4% done at 0.2 kB/s
> > 
> > that ".983 distributed copies" has been creeping upwards.  last i looked
> > at it, about 15 minutes ago, it was at .97.   i've noticed this happen
> > before too.
> > 
> > how exactly does that number increase when there are no seeds?
> 
> Hi, Pete,
>    My research project this summer concerns BitTorrent. (Although I'm
> currently working on the choking algorithm, not the piece selection
> algorithm.) What program is giving you the display right now? Is it a
> client, or a tracker on the web? I don't see the string "distributed"
> anywhere in Bram Cohen's 3.4.2 sources.
 
hey ken,

i'm using something i installed by "hand".  i'm such a casual bittorrent
users (and it was installed so long ago) that i no longer remember which
bittorrent implementation it is.   however, whatever it is, it has 3
clients:

btdownloadgui.py
btdownloadcurses.py (what i always use)
btdownloadheadless.py

i can't remember why i installed it by hand.  maybe debian didn't have
the packages at that time.  or maybe they were broken.   in any event,
it feels like a hackey thing.  there isn't even a --version or -v
option.

i really ought to upgrade though.  i'm getting more and more trackers
telling me i can't connect because my client doesn't support some kind
of compression protocol.

i notice on debian there's:

   un  bittornado
   un  bittornado-gui
   un  bittorrent

i'll give one of them a try.  maybe bittornado.  it sounds very
powerful.    ;-)    ;-)

i realize this email may look ridiculous -- i really am a VERY casual
bittorrent user.  i know a little bit about the protocol because i like
reading about it more than actually downloading a gazillion gigs of
stuff.

pete


-- 
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