This commit provides a detailed overview of the current block download
method, which I've retroactively named blocks-first for parallelism with
headers-first.
New And Significantly Revised:
* New Initial Block Download (IBD) section (h3) with Blocks-First
subsection (h4)
* New Orphan Block subsection (under Blocks Broadcasting) describing
orphan blocks and how they're handled under blocks-first. Also
includes a simple illustration of the difference between orphan blocks
and stale blocks. Thanks to luke-jr for his s/orphan block/stale
block/ commit a couple months ago---that made this commit much easier.
Edits:
* Cleaned up a couple cases missed by previous s/orphan/stale/ commit
because they used past tense (orphaned).
* In P2P reference section, mentioned that a `block` message can be sent
unsolicited by miners.
* Mention that `getheaders` and `headers` were added in protocol
version 31800.
* Moved a few internal links around and added a few new internal links.
Administrivia:
* Started adding "TODOv0.10" in HTML comments to places that need to be
updated when 0.10 is released so that I can easily git grep for that
tag later.
As discussed on BitcoinTalk, there was confusion about whether a
non-upgraded node would switch to the strongest chain despite that chain
not following the consensus rules known to the non-upgraded node. Also
updated to mention Bitcoin Core 0.10.0 now that it's RC'd.
Ref: https://bitcointalk.org/index.php?topic=909732.msg9999032#msg9999032
Based on a suggestion made by @petertodd to the -devel mailing list and
the discussion in that thread by him and other participants.
* We've been using the term "consensus", but this commit introduces a
formal definition for it and "consensus rules" as part of the block
chain introduction.
* Describe that consensus rules may change and may happen when they
do: hard or soft forks.
* Describe how full nodes can detect hard or soft forks, then describe
how SPV clients can detect hard and soft forks using the more limited
information available to them.
Thanks also (in alphabetical order) to @cbeams, @mikehearn, and
@tgeller, among others.
The last pre-squash commit was: c2b8d562aa107c7b68c60946cea14cdccc5159ad
