* [9fans] Venti by another name
@ 2009-02-14 15:34 matt
2009-02-14 17:40 ` Devon H. O'Dell
` (2 more replies)
0 siblings, 3 replies; 10+ messages in thread
From: matt @ 2009-02-14 15:34 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
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.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [9fans] Venti by another name
2009-02-14 15:34 [9fans] Venti by another name matt
@ 2009-02-14 17:40 ` Devon H. O'Dell
2009-02-15 1:55 ` Joel C. Salomon
2009-02-16 5:37 ` Eris Discordia
2 siblings, 0 replies; 10+ messages in thread
From: Devon H. O'Dell @ 2009-02-14 17:40 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
On this note, Marco Peereboom has been working on epitome:
http://www.peereboom.us/epitome
--dho
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [9fans] Venti by another name
2009-02-14 15:34 [9fans] Venti by another name matt
2009-02-14 17:40 ` Devon H. O'Dell
@ 2009-02-15 1:55 ` Joel C. Salomon
2009-02-16 5:37 ` Eris Discordia
2 siblings, 0 replies; 10+ messages in thread
From: Joel C. Salomon @ 2009-02-15 1:55 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
On Sat, Feb 14, 2009 at 10:34 AM, matt <mattmobile@proweb.co.uk> wrote:
> 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.
Sounds vaguely like Freenet.
—Joel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [9fans] Venti by another name
2009-02-14 15:34 [9fans] Venti by another name matt
2009-02-14 17:40 ` Devon H. O'Dell
2009-02-15 1:55 ` Joel C. Salomon
@ 2009-02-16 5:37 ` Eris Discordia
2009-02-16 12:13 ` matt
2 siblings, 1 reply; 10+ messages in thread
From: Eris Discordia @ 2009-02-16 5:37 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
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
<mattmobile@proweb.co.uk> 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.
>
>
>
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [9fans] Venti by another name
2009-02-16 5:37 ` Eris Discordia
@ 2009-02-16 12:13 ` matt
2009-02-16 14:42 ` Eris Discordia
2009-02-25 0:26 ` Enrico Weigelt
0 siblings, 2 replies; 10+ messages in thread
From: matt @ 2009-02-16 12:13 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
>
> 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.
>
Only if there are shared blocks. Macro blocks in MPEG are 8x8 pixels
which makes them < 32k in size. If you're lucky you might just align
them when written to Venti!
I'll know soon enough as I'm in the process of building a Venti store
for our video files. I just wondered if anyone had done it already.
I doubt there's much in it.
Matt
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [9fans] Venti by another name
2009-02-16 12:13 ` matt
@ 2009-02-16 14:42 ` Eris Discordia
2009-02-25 0:26 ` Enrico Weigelt
1 sibling, 0 replies; 10+ messages in thread
From: Eris Discordia @ 2009-02-16 14:42 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
> I'll know soon enough as I'm in the process of building a Venti store for
> our video files. I just wondered if anyone had done it already.
That kindles in me the bystander's interest. It'd be nice of you to report
back on results.
--On Monday, February 16, 2009 12:13 PM +0000 matt
<mattmobile@proweb.co.uk> wrote:
>
>>
>> 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.
>>
> Only if there are shared blocks. Macro blocks in MPEG are 8x8 pixels
> which makes them < 32k in size. If you're lucky you might just align them
> when written to Venti!
>
> I'll know soon enough as I'm in the process of building a Venti store for
> our video files. I just wondered if anyone had done it already.
>
> I doubt there's much in it.
>
> Matt
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [9fans] Venti by another name
2009-02-16 12:13 ` matt
2009-02-16 14:42 ` Eris Discordia
@ 2009-02-25 0:26 ` Enrico Weigelt
2009-02-25 1:05 ` Roman V. Shaposhnik
1 sibling, 1 reply; 10+ messages in thread
From: Enrico Weigelt @ 2009-02-25 0:26 UTC (permalink / raw)
To: Fans of the OS Plan 9 from Bell Labs
* matt <mattmobile@proweb.co.uk> wrote:
Hi,
> I'll know soon enough as I'm in the process of building a Venti store
> for our video files. I just wondered if anyone had done it already.
I'm actually using venti for storing media files in my MCloud
platform, which is used for several of my customer's portals,
(eg: http://www.television-europe.eu/).
But I really can't tell anything about the space saving.
(one of the primary decision for venti is that it will be
clustered some day ... ;-o)
cu
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^ permalink raw reply [flat|nested] 10+ messages in thread
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-- links below jump to the message on this page --
2009-02-14 15:34 [9fans] Venti by another name matt
2009-02-14 17:40 ` Devon H. O'Dell
2009-02-15 1:55 ` Joel C. Salomon
2009-02-16 5:37 ` Eris Discordia
2009-02-16 12:13 ` matt
2009-02-16 14:42 ` Eris Discordia
2009-02-25 0:26 ` Enrico Weigelt
2009-02-25 1:05 ` Roman V. Shaposhnik
2009-02-25 3:56 ` Enrico Weigelt
2009-02-25 4:29 ` lucio
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