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Add leader rotation links

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Avoid the term "leader selection" here. More precise terms are
"leader scheduling", "leader rotation", and "fork selection."
This commit is contained in:
Greg Fitzgerald
2018-11-28 16:26:38 -07:00
committed by Grimes
parent 070d6a2faa
commit 99445f475b
3 changed files with 15 additions and 12 deletions
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2
book/src/SUMMARY.md
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@ -11,7 +11,7 @@
- [A Solana Cluster](cluster.md) - [A Solana Cluster](cluster.md)
- [Synchronization](synchronization.md) - [Synchronization](synchronization.md)
- [Ledger Replication](storage.md) - [Ledger Replication](storage.md)
- [Leader Rotation](leader-scheduler.md) - [Leader Rotation](leader-rotation.md)
- [Anatomy of a Fullnode](fullnode.md) - [Anatomy of a Fullnode](fullnode.md)
- [TPU](tpu.md) - [TPU](tpu.md)

2
book/src/leader-scheduler.md → book/src/leader-rotation.md
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@ -7,7 +7,7 @@ what node is the leader, how that mechanism may choose different leaders at the
## Leader Seed Generation ## Leader Seed Generation
Leader selection is decided via a random seed. The process is as follows: Leader scheduling is decided via a random seed. The process is as follows:
1. Periodically, at a specific PoH tick count, select the signatures of the votes that made up the last supermajority 1. Periodically, at a specific PoH tick count, select the signatures of the votes that made up the last supermajority
2. Concatenate the signatures 2. Concatenate the signatures

23
book/src/synchronization.md
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@ -41,7 +41,8 @@ A Verifiable Delay Function is conceptually a water clock where its water marks
can be recorded and later verified that the water most certainly passed can be recorded and later verified that the water most certainly passed
through. Anatoly describes the water clock analogy in detail here: through. Anatoly describes the water clock analogy in detail here:
[water clock analogy](https://medium.com/solana-labs/proof-of-history-explained-by-a-water-clock-e682183417b8) [water clock
analogy](https://medium.com/solana-labs/proof-of-history-explained-by-a-water-clock-e682183417b8)
The same technique has been used in Bitcoin since day one. The Bitcoin feature The same technique has been used in Bitcoin since day one. The Bitcoin feature
is called nLocktime and it can be used to postdate transactions using block is called nLocktime and it can be used to postdate transactions using block
@ -56,7 +57,8 @@ theoretical limit of 710,000 transactions per second.
## Proof of History ## Proof of History
[Proof of History overview](https://medium.com/solana-labs/proof-of-history-a-clock-for-blockchain-cf47a61a9274) [Proof of History
overview](https://medium.com/solana-labs/proof-of-history-a-clock-for-blockchain-cf47a61a9274)
### Relationship to Consensus Mechanisms ### Relationship to Consensus Mechanisms
@ -81,11 +83,12 @@ A desirable property of a VDF is that verification time is very fast. Solana's
approach to verifying its delay function is proportional to the time it took to approach to verifying its delay function is proportional to the time it took to
create it. Split over a 4000 core GPU, it is sufficiently fast for Solana's create it. Split over a 4000 core GPU, it is sufficiently fast for Solana's
needs, but if you asked the authors the paper cited above, they might tell you needs, but if you asked the authors the paper cited above, they might tell you
(and have) that Solana's approach is algorithmically slow it shouldn't be ([and have](https://github.com/solana-labs/solana/issues/388)) that Solana's
called a VDF. We argue the term VDF should represent the category of verifiable approach is algorithmically slow it shouldn't be called a VDF. We argue the
delay functions and not just the subset with certain performance term VDF should represent the category of verifiable delay functions and not
characteristics. Until that's resolved, Solana will likely continue using the just the subset with certain performance characteristics. Until that's
term PoH for its application-specific VDF. resolved, Solana will likely continue using the term PoH for its
application-specific VDF.
Another difference between PoH and VDFs used only for tracking duration, is Another difference between PoH and VDFs used only for tracking duration, is
that PoH's hash chain includes hashes of any data the application observed. that PoH's hash chain includes hashes of any data the application observed.
@ -93,7 +96,7 @@ That data is a double-edged sword. On one side, the data "proves history" -
that the data most certainly existed before hashes after it. On the side, it that the data most certainly existed before hashes after it. On the side, it
means the application can manipulate the hash chain by changing *when* the data means the application can manipulate the hash chain by changing *when* the data
is hashed. The PoH chain therefore does not serve as a good source of is hashed. The PoH chain therefore does not serve as a good source of
randomness whereas a VDF without that data could. Solana's leader selection randomness whereas a VDF without that data could. Solana's [leader rotation
algorithm (TODO: add link), for example, is derived only from the VDF *height* algorithm](#leader-rotation), for example, is derived only from the VDF
and not its hash at that height. *height* and not its hash at that height.