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docs: linkification, wording improvements.

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david-sarah 2010-12-12 12:12:34 -08:00
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26
docs/architecture.rst
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@ -39,7 +39,7 @@ about the file they point to. Therefore, the same file may be associated with
different metadata if it is referred to through different edges.
The top layer consists of the applications using the filesystem.
Allmydata.com uses it for a backup service: the application periodically
Allmydata.com used it for a backup service: the application periodically
copies files from the local disk onto the decentralized filesystem. We later
provide read-only access to those files, allowing users to recover them.
There are several other applications built on top of the Tahoe-LAFS
@ -104,7 +104,7 @@ used for both server selection (described below) and to index shares within
the Storage Servers on the selected nodes.
The client computes secure hashes of the ciphertext and of the shares. It
uses Merkle Trees so that it is possible to verify the correctness of a
uses `Merkle Trees`_ so that it is possible to verify the correctness of a
subset of the data without requiring all of the data. For example, this
allows you to verify the correctness of the first segment of a movie file and
then begin playing the movie file in your movie viewer before the entire
@ -123,6 +123,8 @@ bytes will obtain the blocks from storage servers, use erasure-decoding to
turn them into segments of ciphertext, use the decryption key to convert that
into plaintext, then emit the plaintext bytes to the output target.
.. _`Merkle Trees`: http://systems.cs.colorado.edu/grunwald/Classes/Fall2003-InformationStorage/Papers/merkle-tree.pdf
Capabilities
============
@ -526,16 +528,16 @@ granularity: having only one node means a single point of failure, no matter
how many copies of the file you make. Independent nodes (with uncorrelated
failures) are necessary to hit the mathematical ideals: if you have 100 nodes
but they are all in the same office building, then a single power failure
will take out all of them at once. The "Sybil Attack" is where a single
attacker convinces you that they are actually multiple servers, so that you
think you are using a large number of independent nodes, but in fact you have
a single point of failure (where the attacker turns off all their machines at
once). Large grids, with lots of truly independent nodes, will enable the use
of lower expansion factors to achieve the same reliability, but will increase
overhead because each node needs to know something about every other, and the
rate at which nodes come and go will be higher (requiring network maintenance
traffic). Also, the File Repairer work will increase with larger grids,
although then the job can be distributed out to more nodes.
will take out all of them at once. Pseudospoofing, also called a "Sybil Attack",
is where a single attacker convinces you that they are actually multiple
servers, so that you think you are using a large number of independent nodes,
but in fact you have a single point of failure (where the attacker turns off
all their machines at once). Large grids, with lots of truly independent nodes,
will enable the use of lower expansion factors to achieve the same reliability,
but will increase overhead because each node needs to know something about
every other, and the rate at which nodes come and go will be higher (requiring
network maintenance traffic). Also, the File Repairer work will increase with
larger grids, although then the job can be distributed out to more nodes.
Higher values of ``N`` increase overhead: more shares means more Merkle hashes
that must be included with the data, and more nodes to contact to retrieve

9
docs/frontends/CLI.rst
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@ -356,17 +356,14 @@ Command Examples
``tahoe put file.txt tahoe:subdir/foo.txt``
``tahoe put file.txt DIRCAP/foo.txt``
or
``tahoe put file.txt DIRCAP:./foo.txt``
``tahoe put file.txt DIRCAP/subdir/foo.txt``
or
``tahoe put file.txt DIRCAP:./subdir/foo.txt``
These upload the named file and attach them to a subdirectory of the given
root directory, under the name "``foo.txt``". When a directory write-cap is
given, you can use either ``/`` or ``:./`` to separate it from the following
path. When the source file is named "``-``", the contents are taken from stdin.
given, you can use either ``/`` (as shown above) or ``:./`` to separate it
from the following path. When the source file is named "``-``", the contents
are taken from stdin.
``tahoe put file.txt --mutable``