From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 16 Feb 2009 05:37:01 +0000 From: Eris Discordia To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Message-ID: <245FD45C87AA3D8874EE92CD@[192.168.1.2]> In-Reply-To: <4996E472.5010905@proweb.co.uk> References: <4996E472.5010905@proweb.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Subject: Re: [9fans] Venti by another name Topicbox-Message-UUID: a131f6c2-ead4-11e9-9d60-3106f5b1d025 BitTorrent protocol chops the upload into same-sized blocks and hashes each block. Then the blocks are traded. It predates other P2P protocols that do so. I don't know about anonymity/privacy guards (FreeNet was mentioned). In BT these hashes are contained in the torrent file and used for integrity checking so it can't be correlated with venti. OFF's idea seems okay but it's rather trite. You can always represent copyrighted content in different ways, pass it on, and claim you haven't exchanged the "copyrighted bytes." That's why you are barred by the DMCA from transcoding even for personal use the content for which you have an "only personal home use" license (of course, you abide the law, don't you ;-). The person who did the transform/transcoding is still legally liable. Also, you can always create a lookup table of all possible bit sequences of a certain length and represent your data (padded to a multiple of that length) as a chain of such sequences. That's no wonderwork. > I've not pushed any mpeg data into venti, though I have idly wondered if > there are any disk saving. Can any lossless compression scheme improve on {J,M}PEG? If multiple streams are stored in venti then there may be some common blocks but even that should not significantly surpass RAR algorithm's "solid" archiving of the same streams. Not that I understand these things. --On Saturday, February 14, 2009 3:34 PM +0000 matt wrote: > I came across this today > > http://offsystem.sourceforge.net/ > > It's a P2P system where data blocks are traded not files. > > A file becomes a set of blocks and if requested, anyone who has the block > can supply the data, even if they don't possess the same file. > > In that way no-one is sharing copyrighted material in the large, just > coincedent blocks. > > I've not pushed any mpeg data into venti, though I have idly wondered if > there are any disk saving. > > > >