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docs: edits and updates to architecture.txt, with Amber

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Zooko O'Whielacronx 2008-02-13 10:24:52 -07:00
parent 2e84230a18
commit e400c5a8fb
1 changed files with 9 additions and 9 deletions
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docs/architecture.txt
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@ -30,7 +30,7 @@ applications, too.
THE GRID OF STORAGE SERVERS THE GRID OF STORAGE SERVERS
The grid is composed of a collection of peer nodes -- processes running on The grid is composed of peer nodes -- processes running on
computers. They establish TCP connections to each other using Foolscap, a computers. They establish TCP connections to each other using Foolscap, a
secure remote message passing library. secure remote message passing library.
@ -47,8 +47,8 @@ all other peers from it. Each peer then connects to all other peers,
creating a fully-connected topology. In the current release, nodes creating a fully-connected topology. In the current release, nodes
behind NAT boxes will connect to all nodes that they can open behind NAT boxes will connect to all nodes that they can open
connections to, but they cannot open connections to other nodes behind connections to, but they cannot open connections to other nodes behind
NAT boxes. Therefore, the more nodes there are behind NAT boxes the NAT boxes. Therefore, the more nodes behind NAT boxes, the less the
less the topology resembles the intended fully-connected topology. topology resembles the intended fully-connected topology.
FILE ENCODING FILE ENCODING
@ -57,15 +57,15 @@ When a peer stores a file on the grid, it first encrypts the file,
using a key that is optionally derived from the hash of the file using a key that is optionally derived from the hash of the file
itself. It then segments the encrypted file into small pieces, in itself. It then segments the encrypted file into small pieces, in
order to reduce the memory footprint, and to decrease the lag between order to reduce the memory footprint, and to decrease the lag between
initiating a download and receiving the first part of the file, for initiating a download and receiving the first part of the file; for
example the lag between hitting "play" and a movie actually starting. example the lag between hitting "play" and a movie actually starting.
The peer then erasure-codes each segment, producing blocks such that The peer then erasure-codes each segment, producing blocks such that
only a subset of the blocks (by default 3 out of 12 of the blocks) are only a subset of them are needed to reconstruct the segment (by
needed to reconstruct the segment. The peer uploads each block to a default 3 out of 12 of the blocks). It sends one block from each
storage server. It sends one block from each segment to a given segment to a given server. The set of blocks on a given server
server, creating a "share" stored on that server. Only a subset of constitutes a "share". Only a subset of the shares (3 out of 12) are
the shares (3 out of 12) are needed to reconstruct the file. needed to reconstruct the file.
A tagged hash of the encryption key is used to form the "storage A tagged hash of the encryption key is used to form the "storage
index", which is used for both server selection (described below) and index", which is used for both server selection (described below) and