Newsgroups: alt.consumers.free-stuff,rec.arts.sf.written
From: Charlie Stross
Subject: Re: Baen Free Ebook CD ISOs Torrenting
References: <40413e5e.1157440557@netnews.att.net>
Organization: foobar quux
Reply-To: charlie@antipope.org
User-Agent: slrn/0.9.7.4 (Darwin)
Date: Sun, 29 Feb 2004 15:44:25 +0000
Message-ID:
NNTP-Posting-Date: Sun, 29 Feb 2004 15:45:01 +0000
Stoned koala bears drooled eucalyptus spittle in awe
as declared:
>>This is basically the same as putting it on a website for direct
>>download, except it harnesses the upstream bandwidth of downloaders to
>>get it distributed faster without slashdotting the host site.
>
> Yes, I understand that. I also understand why you might want to bittorrent
> something like a bootleg concert or the like (that's a general "you", not
> you in particular), but I still dont' see the point given that all these
> files are available for public download from baen.com.
Because ... hell. Let's say Baen puts up a CD ISO image, right? 500Mb of
data. Now let's say 1000 people want that image. If it's distributed via
FTP or HTTP, Baen has to send the whole thing 1000 times, for a total
of 500Gb of data transfer. Since the collapse of the MBone we don't have
an effective multicast system -- but BitTorrent distributes the
unicasting workload, so Baen probably only sends the whole thing out a
couple of times, for 1Gb of data transfer, and the BitTorrent network
spreads it around for, say, another 1Gb of bandwidth per customer.
Now imagine 10,000 people want the CD image. If Baen do it the
traditional way, they need 5Tb of bandwidth -- which costs serious money
(we're talking about the full capacity of a T1 line for two months). But
via BitTorrent, they're *still* only using the same 1Gb, plus about 1Gb
per customer.
Bandwidth isn't free, but BitTorrent makes it a lot cheaper for Baen (or
other wholesale sources of data) to distribute entire CD images by
spreading the cost among the interested audience. A working multicast
system would be technically better, but distributed p2p networks are a
decent stopgap solution.
-- Charlie