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[Gzz-commits] manuscripts/pointers article.rst
From: |
Tuomas J. Lukka |
Subject: |
[Gzz-commits] manuscripts/pointers article.rst |
Date: |
Tue, 04 Nov 2003 05:03:27 -0500 |
CVSROOT: /cvsroot/gzz
Module name: manuscripts
Branch:
Changes by: Tuomas J. Lukka <address@hidden> 03/11/04 05:03:27
Modified files:
pointers : article.rst
Log message:
Intro
CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/manuscripts/pointers/article.rst.diff?tr1=1.121&tr2=1.122&r1=text&r2=text
Patches:
Index: manuscripts/pointers/article.rst
diff -u manuscripts/pointers/article.rst:1.121
manuscripts/pointers/article.rst:1.122
--- manuscripts/pointers/article.rst:1.121 Tue Nov 4 04:49:37 2003
+++ manuscripts/pointers/article.rst Tue Nov 4 05:03:27 2003
@@ -63,13 +63,13 @@
no central point of failure for a Web page; it could be downloaded
from any host that has a copy. This would save bandwidth
and increase availability. However, if the Web worked like
-a filesharing system, Web pages could never be updated.
-
-Some filesharing systems offer URIs for files
-(e.g., [freenet-ieee-andalso-edonkey2kurl]_).
-These URIs are based on the files' cryptographic hashes.
+a filesharing system, Web pages could not be updated easily.
+Some filesharing systems offer permanent URIs for files
+(e.g., [freenet-ieee-andalso-edonkey2kurl]_),
+based on the files' cryptographic hashes.
A new version of a Web page would have a different hash,
-and thus a different URI.
+and thus a different URI. Others could be confused by
+finding two files with the same name but different content (XXX).
There are some (non-filesharing) P2P systems
that do offer an update mechanism. *CFS* [dabek01widearea]_
@@ -84,7 +84,7 @@
In *OceanStore* [kubiatowicz00oceanstore]_,
an Internet-scale distributed data store that
-allows users to keep their files save and access them
+allows users to access their files
from different locations, every document has a
*primary replica*, a small set of servers that
maintain the current version of the document.
@@ -93,15 +93,17 @@
containing a document id, the hash of a version,
a timestamp and a serial version number.
To obtain the most current version, one sends a request
-to the primary replica. Many applications, however,
-are believed to be able to cope with looser consistency
-semantics; the NFS client for CFS only requests
-new heartbeats less than 30 seconds old.
+to the primary replica [#consistencytime]_.
OceanStore is unique among the versioned P2P systems
in that it implements non-destructive updates,
allowing previous versions of documents to be accessed
(by using their old heartbeats).
+.. [#consistencytime] Many applications
+ are believed to be able to cope with looser consistency
+ semantics; for example, the NFS client for CFS only requests
+ new heartbeats less than 30 seconds old.
+
*Freenet*, a P2P network for anonymous publication [freenet-ieee]_,
was originally planned to have an
update mechanism where the network would remember
@@ -149,9 +151,9 @@
Thus, in these systems, when the original publisher loses interest
and stops publishing a page, it disappears, even if
-someone else would have kept a copy.
+someone else has kept a copy.
-This is an important concern.
+This is an important concern, as seen by the following example.
In 1997, NASA launched the Cassini-Huygens spacecraft
on a mission to Saturn. Before the launch, the mission
was widely criticized for its use of radioisotope
@@ -162,16 +164,17 @@
SpaceViews, a publication of the National Space Society,
published a list of links to web pages of both
Cassini opponents and supporters [#rtg-links]_.
+In the year 2003,
+only six years after the launch,
+only 29
+of the 83 links provided by SpaceViews continue to work.
+Almost two thirds of the debate
+has fallen off the Web. "If I have seen further it is by standing
+on the shoulders of giants;" but how can we do that today,
+if the shoulders keep rotting away?
.. [#rtg-links] ``http://www.seds.org/spaceviews/cassini/ rtgpages.html``.
All links dereferenced on October 27th, 2003.
-
-
-Of the 83 links provided by SpaceViews, only 29 continue to work in 2003.
-Only six years after the launch, almost two thirds of the debate
-have fallen off the Web. "If I have seen further it is by standing
-on the shoulders of giants;" but how can we do that today,
-if the shoulders keep rotting away?
(The Internet Archive's Wayback Machine [waybackmachine]_
alleviates these concerns, but it introduces
- Re: [Gzz-commits] manuscripts/pointers article.rst, (continued)
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/04
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/04
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/04
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/04
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/04
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/04
[Gzz-commits] manuscripts/pointers article.rst,
Tuomas J. Lukka <=
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/04
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/04
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/05
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/05
[Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/11/05
[Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/11/05
[Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/11/05
[Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/11/05
[Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/11/05
[Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/11/05