[vox-tech] bittorrent

[Peter Jay Salzman]

On Thu 04 Dec 03,  2:17 PM, Jeff Newmiller <jdnewmil@dcn.davis.ca.us> said:
> On Thu, 4 Dec 2003, Peter Jay Salzman wrote:
> 
> > ok, i've downloaded bittorrent on debian/sarge.  now what?
> > 
> > i've read some material, and here's what i think i know:
> > 
> > 1. to get the best download speeds, i'll need to poke holes in
> >    tcp/6881 through tcp/6889.
> 
> Actually, poking holes enables uploads... which in turn prompts recipients
> of your largesse to give you higher priority... leading to generally
> faster downloads.
 
yeah, i read all about that.  if peers don't hear from me, they start to
ignore me.  i spent a few hours reading about bittorrent.  it's a neat
concept.

> I only poke one hole at 6881, because I only do one file at a time.  If
> you want to be able to do more simultaneous downlads, then poke more
> holes.  In my case, the download usually sucks up most of my bandwidth, so
> running more than one instance at a time doesn't really make much sense.
 
i'm on symmetric cable, and it's a bit faster than what i was used to
with DSL.  i plan on doing only one file too, but i think it'd make
sense for me to have a couple of ports open so multiple people can
request chunks from me.

> > 2. i need to open a web browser, find a bittorrent link, and click on
> >    it, which will open up the bittorrent helper application and engage
> >    in the download of whatever the file points to.
> 
> I didn't bother to enable the helper application... I just invoke it
> at the command line.
> 
> In my case, I have a NATing firewall, so I invoke it as
> 
>   $ btdownloadgui.py --ip my.external.ip.address 'torrent_url'

ahh.  ok.

> > that's what i think i know.  how accurate is this?
> 
> Accurate enough to get by, I suppose.
> 
> > how does one find .bittorrent links?
> 
> Google?
> 
> There are some sites that specialize in particular types of
> files... depends what you are looking for.  Slashdot sometimes posts
> links.  They just represent a specialized download protocol.

ok, now THAT part is lame.  i've been googling for awhile now.

p2p like gnutella and fasttrack makes it easy to find what you want, but
difficult to get it.

bittorrent makes things easy to get, but difficult to find.

> > does anyone have a bittorrent testfile handy to download some very small
> > text file in a 'Hello World' fashion?
> 
> Seems not much point to this, since BT can take 5 or 10 MB to get into the
> swing of things.  If you really want to download a small file,
> www.toriyamaworld.com regularly distributes translated manga scans (2-6MB)
> using BT.

i just wanted to see it in action.  i had no desire to download a DVD or
2GB games.

but i see what you mean.  very interesting -- it downloaded, but the bt
app is still alive, and it appears to be uploading.   that's kind of
neat: post mortem uploads.  :)

> Some additional notes:
> 
> a) Sarge doesn't have the newest bittorrent...  but I don't know that this
> is so terrible.  The newer version (3.3) is supposed to be a little more
> efficient, and it reports accumulated upload and download amounts which
> gives you an idea of how much you have contributed back to the torrent,
> but the older version still works.

it appears that sarge now has 3.3.  :)  is your copy being "held back"?

> b) Don't be surprised when the whole file appears on your hard disk
> immediately.  BT downloads random chunks, so it has to do this... but the
> file won't be usable until BT says the whole thing is downloaded.
 
ok, thanks for the heads up.  jigdo does the exact same thing when
downloading debian images.

> c) You can stop and restart your download at will. (Restarting is exactly
> the same as starting.) BT will automatically pick up where it left off.  
> Corollary: you can start a BT download on a file you already have
> completed if you want to help upload... this is known as seeding.

awesome.  by the time my 3MB download was finished, i uploaded 0MB.

as i write this, i've already uploaded 7.3 MB.

i wish there was a setting to throttle the bandwidth.

> d) Note the number of seeds on a download before you begin (a nice torrent
> manager will set up a tracker to provide you with these statistics)... if
> you have half the file and the last seed disconnects, your download will
> never complete.  Ergo, communicating with someone who _has_ downloaded the
> whole file and asking them to seed for you may be necessary if a torrent
> is no longer popular.
 
sounds like a good thing to be aware of.  i've seen websites that tell
you the number of seeds (before your email i didn't know what a seed
was).

is there a utility that i can use to query the torrent manager?  in
other words, if the website i download the .torrent file doesn't have
the info, is there another way for me to get it?


thanks jeff!
pete

-- 
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