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=============== |
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The Web and many other hypermedia systems assume that identifiers |
The Web and many other hypermedia systems assume that identifiers |
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either have to include location information (as in URLs, which break |
either have to include location information (as in regular URLs, which break |
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when documents are moved), or can only be resolved locally (as in |
when documents are moved), or can only be resolved locally (as in |
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link services that can only find links stored on a select set |
link services that can only find links stored on a select set |
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of link servers [ref Microcosm, DLS, ...]). Berners-Lee [ref NameMyth - that |
of link servers [ref Microcosm, DLS, ...]). Berners-Lee [ref NameMyth - that |
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[ref chord, can, tapestry, pastry, kademlia, symphony, viceroy, |
[ref chord, can, tapestry, pastry, kademlia, symphony, viceroy, |
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skip graph, swan, kelips] allow location-independent identifiers |
skip graph, swan, kelips] allow location-independent identifiers |
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to be resolved on a global scale. |
to be resolved on a global scale. |
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Thus, it is now feasible to do a global search to find all information |
Thus, it is now possible to perform a global lookup to find all information |
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related to a given identifier on any participating peer in the network. |
related to a given identifier on any participating peer in the network. |
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This, we believe, may be the most important result of peer-to-peer |
This, we believe, may be the most important result of peer-to-peer |
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research with regard to hypermedia. |
research with regard to hypermedia. |
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We examine how location-independent identifiers can support *data mobility*. |
In this paper, we examine how location-independent identifiers can |
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In today's computing world, documents move quite freely between |
support *data mobility*. Our motivation has been inspired by today's computing |
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computers: they are sent as e-mail attachments, carried around on disks, |
world, in which documents move quite freely between computers: they are sent as |
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published on the web, moved between desktop and laptop systems, |
e-mail attachments, carried around on disks, published on the web, moved |
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downloaded for off-line reading or copied between computers in a LAN. |
between desktop and laptop systems, downloaded for off-line reading or |
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We use 'data mobility' as a collective term for the movement of documents |
copied between computers in a LAN. We use 'data mobility' as a collective |
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between computers (or folders!), |
term for the movement of documents between computers (or folders!), |
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and movement of content between documents (through copy&paste) [#]_. |
and movement of content between documents (through copy&paste) [#]_. |
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.. [#] While the physical mobility of e.g. notebooks may effect |
.. [#] While the physical mobility of e.g. notebooks may effect |
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data mobility is neither the same as, nor limited to the physical |
data mobility is neither the same as, nor limited to the physical |
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movement of devices. |
movement of devices. |
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In this paper, we address two issues raised by data mobility: |
We address two issues raised by data mobility: |
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Dangling links and keeping track of alternative versions. |
Dangling links and keeping track of alternative versions. |
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Resolvable location-independent identifiers |
Resolvable location-independent identifiers |
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make these issues much easier to deal with, since data |
make these issues much easier to deal with, since data |
1272 |
8. Conclusions |
8. Conclusions |
1273 |
============== |
============== |
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We have presented the Storm design, which makes use of recent advances |
We have addressed two important issues raised by data mobility, dangling |
1276 |
in peer-to-peer technology to support many different forms |
links and keeping track of alternative versions. Moreover, we have presented |
1277 |
of data mobility. All data is stored in immutable blocks, |
the Storm design, which makes use of recent advances in peer-to-peer technology |
1278 |
of which application-specific indices can be kept. On top of |
to resolve these issues. In Storm, all data is stored as immutable blocks and |
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indexed blocks, we implement efficient versioned storage |
each block has globally unique identifier. Application-specific indices can be kept |
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of mutable resources as well as Xanalogical storage. |
of these blocks. On top of indexed blocks, we have implemented efficient versioned |
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storage of mutable resources as well as Xanalogical storage. |
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Storm is not limited to network publishing; |
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it is intended to be used for private documents stored on |
Storm is not only limited to network publishing; |
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desktop systems as well. Our current implementation does not support |
it can be also used for private document repository. Our current implementation |
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peer-to-peer distribution yet, but the Gzz project has used it |
does not support peer-to-peer distribution yet, but the Gzz project has used it |
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for local storage and server-based collaboration |
for local storage and server-based collaboration for one and a half years. |
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for one and a half years. |
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Storm has proven to be a solid basis for Gzz, but |
Storm has proven to be a solid basis for Gzz, but |
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no work has been done to integrate it with existing systems, yet. |
no work has been done to integrate it with existing systems, yet. |