/[gzz]/manuscripts/storm/short-paper.rst
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revision 1.38 by tjl, Fri May 30 19:34:07 2003 UTC revision 1.39 by benja, Fri May 30 21:08:23 2003 UTC
# Line 13  Storm: Using P2P to make the desktop par Line 13  Storm: Using P2P to make the desktop par
13    
14      \begin{abstract}      \begin{abstract}
15      We present Storm, a storage system which unifies the      We present Storm, a storage system which unifies the
16      desktop and the public network. Storm assigns each document      desktop and the public network, making Web links between
17        desktop documents more practical.
18        Storm assigns each document
19      a permanent unique URI when it is created. Using peer-to-peer      a permanent unique URI when it is created. Using peer-to-peer
20      technology, we can locate documents even though our URIs      technology, we can locate documents even though our URIs
21      do not include location information.      do not include location information.
22      Links continue to work unchanged when documents are emailed      Links continue to work unchanged when documents are emailed
23      or published on the network.      or published on the network.
24      We have extended KDE to understand      We have extended KDE to understand
25      torm URIs. Other systems such as GNU Emacs are able to use Storm      Storm URIs. Other systems such as GNU Emacs are able to use Storm
26      through an HTTP gateway.      through an HTTP gateway.
27      \end{abstract}      \end{abstract}
28    
# Line 73  seem to do so. Line 75  seem to do so.
75  .. non-breaking links seem not globally resolvable:  .. non-breaking links seem not globally resolvable:
76    
77  A major obstacle to hypermedia  A major obstacle to hypermedia
78  on the desktop is broken links. A user receiving  on the desktop are broken links. A user receiving
79  hyperlinked documents by email, for example, would have to reconstruct  hyperlinked documents by email, for example, would have to reconstruct
80  the original directory structure; otherwise the links  the original directory structure; otherwise, the links
81  will not work.  will not work.
82  Many hypermedia systems  Many hypermedia systems
83  assume that identifiers either  assume that identifiers either
# Line 97  allow location-independent identifiers Line 99  allow location-independent identifiers
99  to be resolved on a global scale.  to be resolved on a global scale.
100  Balakrishnan et al.  [balakrishnan03semanticfree]_ argue  Balakrishnan et al.  [balakrishnan03semanticfree]_ argue
101  that DHTs are suitable for the next generation  that DHTs are suitable for the next generation
102  Reference Resolutions Services (RRS) [#]_.  Reference Resolution Services (RRS) [#]_.
103  DHTs can not only be used to efficiently retrieve documents,  DHTs can not only be used to efficiently retrieve documents,
104  but also metadata *about* documents. For example,  but also metadata *about* documents. For example,
105  unlike many link services that only query a limited  unlike many link services that only query a limited
106  set of servers for links [hill94extending]_,  set of servers for links (e.g., [hill94extending]_),
107  all published external links to a document can be found using  all published external links to a document can be found efficiently using
108  a DHT.  a DHT.
109    
110  .. [#] Domain Name System (DNS, RFC 1101) is a widely used RRS  .. [#] The Domain Name System (DNS, RFC 1101) is an RRS
111     system in the Internet.     system widely used on the Internet.
112    
113  .. Freenet's cryptographical identifiers:  .. Freenet's cryptographical identifiers:
114    
# Line 116  a DHT. Line 118  a DHT.
118  Location-independent identifiers enable non-breaking links  Location-independent identifiers enable non-breaking links
119  on the desktop and the Web:  on the desktop and the Web:
120  When a document is published  When a document is published
121  on the Web, it would have the same URI as on the  on the Web, it will have the same URI as on the
122  author's local desktop; when a link to a document is emailed,  author's local desktop; when a link to a document is emailed,
123  the receiver could follow the link as long as their  the receiver can follow the link as long as their
124  software can locate the linked document-- on its local  software can locate the linked-to document-- on its local
125  harddisk, attached to another email, on the work group server  harddisk, attached to another email, on a work group server
126  or on the  or on the
127  public Internet.  public Internet.
128  In Freenet [freenet-ieee]_, an anonymous P2P  In Freenet [freenet-ieee]_, an anonymous P2P
129  publication system, *cryptographic hashes* [#]_  publication system, *cryptographic hashes* [#]_
130  are used for location-independent identifiers of  are used as location-independent identifiers of
131  documents versions.  document versions.
132    
133  ..  [#] A cryptographic hash  ..  [#] A cryptographic hash
134      is short bit-string (often 160 bits)      is short bit-string (often 160 bits)
# Line 162  Storm Line 164  Storm
164  Storm (for STORage Module)  Storm (for STORage Module)
165  is a library for both local and distributed storage  is a library for both local and distributed storage
166  and publishing.  and publishing.
167  On the lowest level, storm handles data in *blocks*  On the lowest level, Storm stores data in *blocks*,
168  which are immutable byte sequences.  which are immutable byte sequences.
169  As opposed to filesystems, Storm uses  As opposed to file systems, Storm
170  uses Freenet-like cryptographic identifiers to  uses Freenet-like cryptographic identifiers.
 manipulate the blocks.  
171  This may seem like a bad tradeoff: while these identifiers  This may seem like a bad tradeoff: while these identifiers
172  enable secure location-independent references, they  enable secure location-independent references, they
173  do not allow  do not allow
174  the documents referred to by the identifiers to change  the identified documents to change
175  and  and
176  are also less comprehensible for humans.  are also less comprehensible to humans.
177  However, these downsides are dealt with by the higher abstraction  However, these downsides are dealt with by the higher abstraction
178  levels  levels
179  of Storm.  of Storm.
# Line 183  One of the key innovations in Storm is t Line 184  One of the key innovations in Storm is t
184  of *pointer blocks*  of *pointer blocks*
185  to build mutable documents on top of  to build mutable documents on top of
186  the lowest layer append-and-delete-only model.  the lowest layer append-and-delete-only model.
187  A pointer block is simply a storm block which says  A pointer block is a Storm block which says
188  "The identifier X points to document Id, and this block overrides  "The identifier *X* points to the current version of
189  the previous pointer blocks a, b" and contains  document *Y*, and this block overrides
190  a digital signature of the above information. The pointer Id  the previous pointer blocks *a, b*" and contains
191    a digital signature of the above information. The pointer *Y*
192  contains the public key used for signatures --- this allows  contains the public key used for signatures --- this allows
193  only the originator of the document to validate new versions.  only the author of the document to validate new versions.
194  A suitable user interface around pointers allows the user to  A suitable user interface around pointers allows the user to
195  still see old-style file names, but with the file names attached  still see old-style file names, but with the file names attached
196  to his/her person, not to a particular computer.  to his/her person, not to a particular computer.

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