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revision 1.53 by benja, Sat Nov 1 20:39:07 2003 UTC revision 1.54 by benja, Sat Nov 1 20:47:09 2003 UTC
# Line 40  What's missing: Why isn't the Web runnin Line 40  What's missing: Why isn't the Web runnin
40  Abstract  Abstract
41  ========  ========
42    
43  If the Web worked like a file-sharing system, there would be  File-sharing systems save bandwidth and increase availability
44  no central point of failure for a Web page; it could be downloaded  because there is no single point of failure for a file.
45  from any host that has a copy. This would save bandwidth  This would be desirable on the Web.
46  and increase availability. However, if the Web worked like  However, most current P2P systems have no facility
47  a file-sharing system, Web pages could never be updated.  for updating documents, and those that do
48    require keeping the current version as state in the network.
49    Thus, to keep a version of a Web page available,
50    it would not suffice to keep a copy on your computer.
51    
52  We present an updating system usable  We present an versioning mechanism usable
53  for a P2P Web as well as for file-sharing (e.g. corrected versions  for a P2P Web as well as for file-sharing (e.g. corrected versions
54  of Project Gutenberg books) and P2P-based software distribution  of Project Gutenberg books) and P2P-based software distribution
55  (akin to Debian's ``apt-get``).  (akin to Debian's ``apt-get``).
56    
 Most current P2P systems have no facility  
 for updating documents. The systems that do  
 require state in the network  
 for remembering what the current version of a document is.  
 Thus, to keep a version of a Web page available,  
 it does not suffice to keep a copy on your computer.  
   
57  Extending OceanStore's "heartbeats," we propose *pointer records*,  Extending OceanStore's "heartbeats," we propose *pointer records*,
58  signed files containing a document's id,  signed files containing a document's id,
59  the hash of its current version, and a timestamp.  its current version's hash, and a timestamp.
60  Pointer records, like other files, can be downloaded from any peer  We can find available pointer records for a document
61  that has a copy. We can find all available pointer records for a document  through the same mechanism we use to find files by hash
62  through the same mechanism we use to find files in the peer-to-peer network  (for example, a DHT).
 (for example, a distributed hashtable).  
63  To find the newest version, we look for the most recent timestamp.  To find the newest version, we look for the most recent timestamp.
64  This way, versions of a document  This way, versions of a document
65  stay available as long as anybody keeps a copy.  stay available as long as anybody keeps a copy.
# Line 84  Introduction Line 79  Introduction
79  .. Introduce location-independent Web idea (citing  .. Introduce location-independent Web idea (citing
80     benefits from hash-based addressing)---     benefits from hash-based addressing)---
81    
82    If the Web worked like a file-sharing system, there would be
83    no central point of failure for a Web page; it could be downloaded
84    from any host that has a copy. This would save bandwidth
85    and increase availability. However, if the Web worked like
86    a file-sharing system, Web pages could never be updated.
87    
88  .. Standing on the shoulders of giants: Example of Web links rotting away  .. Standing on the shoulders of giants: Example of Web links rotting away
89    
90  In 1997, NASA launched the Cassini-Huygens spacecraft  In 1997, NASA launched the Cassini-Huygens spacecraft

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