On 22 Jan 2007, at 09:35, Anne Coleman wrote:
> Thanks Richard!
> Light begins to dawn. Could I download it with mp3 rocket which I use
> to get peer-to-peer music? It reputedly handles video.

I don't know mp3 rocket, but it's unlikely unless it is
specifically designed to function as a torrent client.

Torrents are not straightforward file downloads. A .torrent
file that you obtain initially, describes, amongst other
things, the size of the pieces into which the file is
broken up for transmission. It also defines the "tracker"
- the server that keeps track of the clients wanting the
file. However, clients also acts as servers for pieces of
the file, so a new client can come along and request pieces
of the file from any of the other clients that have already
downloaded it (the tracker, err, tracks this...). Thus the
original source of the file (the "seed") is not overloaded
with download requests - you get pieces of the file from any
client (known as the "swarm") that has already got it and is
offering to serve it up. Your client application stitches
all the parts back together again for you. Acquisition of
the file is truly distributed amongst many computers and
across many internet connections.

In practice, the more clients there are actively downloading
the more effective torrents are. Waterworld is not a high-
demand download (13 clients approx as I type, for episode 3)
and it has taken just under 24 hours now to get about three-
quarters of each episode. 'Trickle' would be a more accurate
description :-)

Part of the limitation is that client applications try to
match your download bandwidth to your upload bandwidth to
balance the "swarm", and as most broadband connections in the
UK are based on ADSL (the 'A' stands for asymmetric) the
typical upstream connection speed is just a fraction of the
downstream connection speed. Cable broadband and DSL (found
mostly in the US) doesn't suffer from this drawback.

--  
Andy Greener
n.b. Whisper
Pangbourne, UK
http://www.nb-whisper.com

"The human brain starts working the moment you are born, and never  
stops until you stand up to speak in public."


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