[Gzz-commits] manuscripts/pointers article.rst

[Benja Fallenstein]

CVSROOT:        /cvsroot/gzz
Module name:    manuscripts
Branch:         
Changes by:     Benja Fallenstein <address@hidden>      03/11/02 13:46:50

Modified files:
        pointers       : article.rst 

Log message:
        rmcrud; leave out diffs for now

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/manuscripts/pointers/article.rst.diff?tr1=1.75&tr2=1.76&r1=text&r2=text

Patches:
Index: manuscripts/pointers/article.rst
diff -u manuscripts/pointers/article.rst:1.75 
manuscripts/pointers/article.rst:1.76
--- manuscripts/pointers/article.rst:1.75       Sun Nov  2 08:00:23 2003
+++ manuscripts/pointers/article.rst    Sun Nov  2 13:46:50 2003
@@ -2,40 +2,6 @@
 What's missing: Why isn't the Web running over P2P?
 ===================================================
 
-.. META:
-
-   (tentative title)
-
-   Title suggestions and comments:
-
-   should somehow say "Versioning on top of a simple basic model"...
-   Totally **distributed** versioning
-   Works even in ad hoc environments
-   ...
-
-   Interoperability between P2P systems
-
-   Important issue: the main message. Is it:
-
-    This is a nice way to do versioning
-
-    This is a distributed block-based versioning system
-
-    This is a distributed block-based system for getting the WWW static pages 
-    feature set from P2P
-
-    This is a way to avoid web rot (the Cassini-Huygens thing) by allowing
-    storage of old versions (this is VERY different from the 
location-independent
-    web name... more like a side effect)
-
-    This is a way to do an ad hoc networking web
-
-
-   The MAIN goal of this work remains unclear and needs
-   discussion. I think our getting this paper in depends on exactly that: 
-   a CLEAR main goal, a good presentation that will generate discussion.
-
-   REAL:
 
 Abstract
 ========
@@ -66,8 +32,8 @@
 This way, versions of a document 
 stay available as long as anybody keeps a copy.
 
-We also present a simple model for storing only the
-differences between versions.
+.. We also present a simple model for storing only the
+   differences between versions.
 
 ..  raw:: latex
 
@@ -169,13 +135,6 @@
 and stops publishing a page, it disappears, even if
 someone else would have kept a copy.
 
-.. <<<In file-sharing systems, versioning
-   would be useful for media files like the e-books
-   distributed by Project Gutenberg [XXXref], which
-   are occasionally updated to fix typographic errors.>>>
-
-.. Standing on the shoulders of giants: Example of Web links rotting away
-
 This is an important concern.
 In 1997, NASA launched the Cassini-Huygens spacecraft
 on a mission to Saturn. Before the launch, the mission
@@ -198,104 +157,20 @@
 alleviates these concerns, but it introduces
 a single point of failure for the *entire* Web!)
 
-.. Links shouldn't break when documents move or
-   publishers lose interest
-
-.. <<<There are two reasons for broken links: Either the original
-   publisher has moved the target document to a new address,
-   or they have stopped publishing it, usually because keeping
-   up a Web page requires some amount of maintenance and they
-   have lost interest.>>>
-
 .. <<<We don't propose that every byte of information ever published
    on the Web has to be kept around forever. However,
    we do believe that as long as someone does keep a copy,
    data should remain accessible, like in a file-sharing system,
    and links should continue to work.>>>
 
-.. Location-independent, semantic-free, *self-verifying* 
-   identifiers (ref SFR paper [balakrishnan03semanticfree]_,
-   [walfish03dns]_); example: hash-based (ref 
-   ``hash`` URN namespace Internet-Draft; ref Freenet & others)
-
-   History of location-dependence: `TBL ref`_ (like in HT'03 paper)
-
-.. <<<This can be accomplished by replacing URIs that include
-   a server name by URIs that are
-
-   - location-independent: do not refer to a particular server
-     that the file is to be downloaded from;
-   - semantic-free: don't include human-readable information;
-     if an identifier is semantic-free, there is no incentive
-     to change it when a site is re-designed;
-   - self-verifying: after downloading an alleged copy of a document,
-     there is a cryptographical algorithm to test whether
-     this is *really* a copy of this document.>>>
-
-.. <<<In 1996, Tim Berners-Lee [name-myth]_ argued that
-   using location-independent, semantic-free identifiers
-   is not viable on a global scale:
-   "[I]f you put information in a name, it decreases its longevity; 
-   if you don't you can't dereference it to a resource.">>>
-
-.. <<<However, as observed in [fallenstein03storm]_, 
-   with the advent of efficient peer-to-peer lookup mechanisms such as 
-   distributed hashtables (DHTs), this observation
-   is no longer true. A DHT is quite able to resolve a
-   hash-based identifier on a global scale,
-   as evidenced by applications like the Cooperative
-   File System (CFS, [dabek01widearea]_) and 
-   the Overnet file sharing client [overneturl]_.>>>
-
-.. SFR (semantic-free referencing) not all that close, 
-   though semantic-free idea shared (SFR takes along 
-   many problems of the Web)
-
-.. <<<(Using DHTs
-   to resolve location-independent identifiers on the Web
-   has been proposed by Balakrishnan et.al. 
-   [balakrishnan03semanticfree-andalso-walfish03dns]_.
-   However, in their work, the location-independent identifier
-   merely points to a Web server administered by the publisher
-   of a Web page; if the original publisher discontinues
-   maintenance of the page, it would still drop off the Web.)>>>
-
-   XXX move to related work?
-
-.. Proposal: A location-independent Web <<<(closest thing is Freenet (ref))>>>
-
-.. <<<The project that is currently closest to this goal is Freenet,
-   a XXX>>>
-
-.. Benefits of hash-based addressing:
-   - Pages easily movable between servers
-   - Data accessible as long as anyone keeps a copy
-   - Load balancing (download from everyone who has a copy)
-   - Can use one addressing scheme with different protocols,
-     searching different networks for the content behind a hash
-   - Verifiable
-   - Same namespace for local and for non-local data
-
 .. <<<Other projects exploit some of the advantages of hash-based
    (storage systems: CFS, PAST; web caching: Squirrel),
    but don't address the Web.>>>
 
-.. <<<The infrastructure behind CFS, PAST and Squirrel: Peer-to-Peer>>>
-
-.. <<<Quite recently, several Peer-to-Peer architectures have been
-   proposed that use hash-based, loc.ind. ids>>>
-
 .. Possibility of desktop integration in ways that the location-dependent
    Web cannot archieve, through the novel combination of
    network transparency and location independence (ref ourselves).
 
-.. However, there's a problem with this: versioning -----
-   Basic problem: Hash-based addressing allows no updates
-
-.. Contributions; structure of this paper ----
-
-.. Main contrib: Pointer records for implementing updating
-
 The main contribution of our paper are *pointer records*,
 a versioning mechanism which is similar to Oceanstore's heartbeats,
 but makes the clients download and store the pointer records
@@ -335,100 +210,21 @@
 in Gnutella or a DHT-based system, using an anonymized system
 like Achord [XXXref] if it contains controversial content.
 
-.. Other contribs:
-   - The idea of a location-independent Web including
-     location-independent version management
-   - Diffs
-
 An additional contribution of this paper is XXX diffs
 
-.. Structure of this paper
-
 The remainder of this paper is structured as follows.
 In Section 2, we introduce pointer records.
 In Section 3, we propose a simple, hash-based data model
 that can be used by P2P Web servers and clients.
-In Section 4, we introduce a scheme for storing only
-the differences between versions, built on our basic
-data model. In Section 5 we discuss other possible applications
-of pointer records, and Section 6 gives an overview of our
-implementation. Section 7 concludes.
-
-
-
-.. Related work
-   ============
-
-   In this section, we briefly summarize how existing peer-to-peer 
-   systems deal with versioning. We have tried to classify peer-to-peer
-   system into four different categories based on their versioning 
-   model below. We conclude that existing peer-to-peer do not provide all the 
-   benefits of hash-based addressing scheme.
-
-  
-   No versioning model
-   -------------------
-
-   PAST [rowstron01storage]_ is a persistent storage system 
-   that uses pastry [rowston01pastry]_ 
-   for locating data in a Peer-to-Peer environment.
-   Nodes and data items are distributed uniformly based on the hash 
-   identifier in a PAST network. Free Haven [dingledine00free]_ 
-   provides a distributed anonymous persistent data storage. It uses 
-   both cryptography and routing techniques to provide anonymity for 
-   the participating peers and splits a file to a number of shares 
-   which are distributed through a network. 
-
-   .. Regular filesharing apps:
-   .. Gnutella
-   .. Fasttrack stack (Kazaa/Morpheus)
-   .. Shareaza (magnet uri's)
-   .. Overnet/eDonkey2000/eMule/MlDonkey (have location-independent 
identifiers, MD4 hashes)
-   .. BitTorrent
-
-   Centralized versioning model
-   ----------------------------
-
-   .. SFS is a network filesystem that does not support of searching
-      docs. IMHO it's not relevant w.r.t. the article (as Mnet is
-      not either)  
-  
-   Like Free Haven, Publius [pub00]_ focuses on anonymity of the
-   participating nodes. Compared to Free Haven, however, Publius
-   has a support for destructive updates. An issue with Publius
-   is that it requires a globally maintained list of participating
-   nodes currently available in a system.
-  
-   OceanStore [kubiatowicz00oceanstore]_ is a global storage system 
-   based on Tapestry [zhao01tapestry]_ routing algorithm. It 
-   supports non-destructive, linearly versioned updates through a 
-   centralized Byzantine agreement protocol. 
-       
-  
-   Network-level destructive versioning
-   ------------------------------------
-
-   CFS [dabek01widearea]_ is based on Chord [stoica01chord]_ and 
-   stores data blocks, fragments of files, and spreads blocks 
-   uniformly through the network based on identifier of a block.
-   CFS has a support for versioning, but in a way that allows 
-   only the publisher of a file system to do a destructive 
-   versioning for a data item. The versioning takes place at
-   network-level since the hash of the data block determines 
-   which host maintains a data block in the overlay.
+In Section 4 we discuss other possible applications
+of pointer records, and Section 5 gives an overview of our
+implementation. Section 6 concludes.
+
+.. In Section 4, we introduce a scheme for storing only
+   the differences between versions, built on our basic
+   data model. 
 
 
-   Miscellaneous versioning models
-   -------------------------------
- 
-   Freenet [freenet-ieee]_ uses a probabilistic routing scheme to 
-   preserve the anonymity of the participating nodes in a network.
-   It uses the "edition" versioning model: one can link 
-   version x to a link representing version y even if version y 
-   does not exist in a system yet.
-
-   .. ??? XXX I don't understand the above AT ALL
-
 
 Pointer records
 ===============
@@ -570,15 +366,15 @@
       algorithm)
 
 
-Diffs
-=====
-
-- when storing all past versions, space may be a problem
-- (not for small text files-- practical experience: 30 MB
-  in half a year of use-- but for things where each version
-  takes 500 KB)
-- old idea: storing only differences
-- XXX
+.. Diffs
+   =====
+ 
+   - when storing all past versions, space may be a problem
+   - (not for small text files-- practical experience: 30 MB
+     in half a year of use-- but for things where each version
+     takes 500 KB)
+   - old idea: storing only differences
+   - XXX
 
 
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