Ticket #798: 798-docs.dpatch

1 patch for repository davidsarah@dev.allmydata.org:/home/darcs/tahoe/trunk:

Mon Aug 30 04:26:05 GMT Daylight Time 2010  david-sarah@jacaranda.org
  * docs/performance.txt, architecture.txt: updates taking into account new downloader. refs #798

New patches:

[docs/performance.txt, architecture.txt: updates taking into account new downloader. refs #798
david-sarah@jacaranda.org**20100830032605
 Ignore-this: 8c6bd16174d4544157df6f602908426f
] {
hunk ./docs/architecture.txt 235
 When downloading a file, the current version just asks all known servers for
 any shares they might have. Once it has received enough responses that it
 knows where to find the needed k shares, it downloads the shares from those
-servers. (This means that it tends to download shares from the fastest
-servers.)
+servers. This means that it tends to download shares from the fastest
+servers. It will prefer to take shares from the first k distinct servers, if
+they respond fast enough.
 
   *future work*
 
hunk ./docs/performance.txt 43
 
 == Downloading B bytes of an A-byte immutable file ==
 
-network: A
+network: B
 memory footprint: 128KiB
 
hunk ./docs/performance.txt 46
-notes: When asked to read an arbitrary range of an immutable file,
-       Tahoe-LAFS will download from the beginning of the file up until
-       it has enough of the file to satisfy the requested read.
-       Depending on where in the file the requested range is, this can
-       mean that the entire file is downloaded before the request is
-       satisfied. Tahoe-LAFS will continue to download the rest of the
-       file even after the request is satisfied, so in any case where the
-       file actually has to downloaded from the grid, reading part of an
-       immutable file will result in downloading all of the immutable
-       file. Ticket #798 is a proposal to change this behavior.
+notes: When Tahoe-LAFS 1.8.0 or later is asked to read an arbitrary range
+       of an immutable file, only the 128-KiB segments that overlap the
+       requested range will be downloaded.
 
hunk ./docs/performance.txt 50
-       Tahoe-LAFS will cache files that are read in this manner for a
-       short while, so subsequent reads of the same file may be served
-       entirely from cache, depending on what part of the file they need
-       to read, what part of the file was read by previous reads, and
-       how much time has elapsed since the last read.
+       (Earlier versions would download from the beginning of the file up
+       until the end of the requested range, and then continue to download
+       the rest of the file even after the request was satisfied.)
 
 == Downloading B bytes of an A-byte mutable file ==
 
}

Context:

[_auto_deps.py: change pycrypto version requirement to avoid https://bugs.launchpad.net/pycrypto/+bug/620253
david-sarah@jacaranda.org**20100829230038
 Ignore-this: e58f98ef262444067fc4b31fad23e40b
] 
[web: refactor rate computation, fixes #1166
francois@ctrlaltdel.ch**20100815141933
 Ignore-this: d25491858e137894142eaa67c75b0439
] 
[docs: update NEWS a bit about New-Downloader
zooko@zooko.com**20100819021446
 Ignore-this: 31a6e2fb0a6e3d19f73481e99070da7a
] 
[misc: add benchmarking tool for spans
zooko@zooko.com**20100819021420
 Ignore-this: 569327a1908a07e5fb634526bed515b2
] 
[docs: doc of the download status page
zooko@zooko.com**20100814054117
 Ignore-this: a82ec33da3c39a7c0d47a7a6b5f81bbb
 ref: http://tahoe-lafs.org/trac/tahoe-lafs/ticket/1169#comment:1
] 
[docs: NEWS: edit English usage, remove ticket numbers for regressions vs. 1.7.1 that were fixed again before 1.8.0c2
zooko@zooko.com**20100811071758
 Ignore-this: 993f5a1e6a9535f5b7a0bd77b93b66d0
] 
[docs: NEWS: more detail about new-downloader
zooko@zooko.com**20100811071303
 Ignore-this: 9f07da4dce9d794ce165aae287f29a1e
] 
[TAG allmydata-tahoe-1.8.0c2
david-sarah@jacaranda.org**20100810073847
 Ignore-this: c37f732b0e45f9ebfdc2f29c0899aeec
] 
Patch bundle hash:
60cb0a0c6f5e5b9a1c654602d153acbaaf3c3b22