Previous posts on this subject; simple-fix, concepts & simulation.
It is clear to most people that we need to fix the badly designed Emergency Difficulty Adjustment (EDA) algorithm that was introduced when Cash started.
Today there was an announcement from the same person that introduced the EDA some months ago, he writes he selected a new algorithm and were planning with miners to hard fork on November 13th.
This sounds like great news, but upon closer reading of the press release there are various very worrying facts.
First of all, the algorithm introduced a month ago by Neil was hardly mentioned. This algorithm has seen the most testing and public discussion. It was put in a short-list by various people. How can it be that the private reviewers didn't get to judge on it?
Equally curious is that the "winner" picked was the idea of the developer of the ABC client. The same person that gave us the flawed EDA. Additionally, the BitPrim adviser gave a political reason as the basis of his choice. Not a technical reason.
The algorithm chosen was previously reviewed and seen as ill-advised. Now there is an updated version that has not actually been reviewed or simulated. I personally have never actually seen the algorithm that was picked.
Is the picked one really the best technical solution? I have not seen any evidence at all to support that conclusion.

How I hope Bitcoin Cash protocol development works

In Bitcoin Cash there are three steps to implementation in the network.
  1. Developers propose changes, single-handedly or in coalitions.
  2. Influential miners choose to adopt the proposed changes (or not).
  3. The economic majority accepts or rejects the changes.
If there is major disagreement somewhere in these three steps, you risk a split, dividing the conflicting interests which from that point will be diverging in different directions.
We should definitely review our process going forward. We want to avoid politics writing the code, and we must do better than they did today.


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I'm surprised that there was no discussion between the teams.
I did not see the discussion on the mailing list and assumed it was done in private between the developers.
Bitcoin Cash is permission-less development thus BitcoinABC can develop and implement what they think is right and the others can or can not implement it.
But in the case of the DAA and a very short time window until the HF it would have been good to coordinate and not risk a chain split because not every team/miner agrees.
The algorithm from TomH was specifically made to fix a known problem in the now chosen algo.
I follow the mailing list and have read multiple articles on yours. The impression I got was that wt-144 was a very good algorithm. (based on the data given by these articles)
nChain: D622 is 3.1% (+/- 1.2% at 95% CI) better in most instances, but there are edge cases against it.
It would be interesting to know these edge cases.
Maybe we can keep the hard fork time and pick a more logical choice to actually move towards. A choice actually based on technical merit.
Bitcoin Cash could be the big winner in the upcoming SegWit2x hard fork and the possible uncertainty in the BTC market.
Thus keeping the fork date is good choice.
Will you release Bitcoin Classic with a different DAA and let the miners and the market decide?
Can we risk a Bitcoin Cash hard fork with a chain split ~3 days before the SegWit2x hard fork?
edit: typo
   11mo ago
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I think this post makes this change seem more malicious than it really is.
all 3 work, I'd be fine with either.
there will be times when it is necessary to re-convene on decisions, this doesn't seem like one of them. Let's get on the same page and work on solving the more important issues that aren't time sensitive.
Do you really want to risk a contentious split so soon just because you didn't get your algorithm chosen?
   11mo ago
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@1meg greg
Do you really want to risk a contentious split just because you didn't get your algorithm chosen?
I have no algorithm on the table, I have no skin in this game. This most assuredly is not about pride or ego on my side.
The question you really should ask is why the ABC announcement makes it sound like it was a team decision, which it wasn't, and why he states he respects the developers and then turns around and disrespects them by ignoring technical opinions and then picking his own design based on absolutely no public data at all.
   11mo ago
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Important post, Tom! Thanks. We've just been released from the shackles of Core. It's too soon to back decisions "just because some leader says so" or out of fear to upset the consensus. I hope Bitcoin Cash chooses the best DAA based on technical facts and at-hand test results. The Bitcoin-ml thread points toward the need for solid arguments if Booth's or Harding's algos are to be disregarded so quickly.
   11mo ago
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Bitcoin Cash has been nothing if not interesting so far. Part of how Core blocks consensus is through the idea that every single person must agree before we move on. If a group of people know they control an overwhelming economic majority of activity blockchain, they have the ability to do whatever they want within their economic group. They as a group can continue using the thing (POW blockchain) they built to their hearts desires, that is they can exchange between themselves freely. My choice as a user is to decide which chain to give my business to, so I have little issue with how this change was made, only how the change performs. Innovation is never fair.
If I was a developer trying to maintain a working implementation however I might be greatly inconvenienced.
I want to see a detailed write-up of these simulations and it'd be nice, but difficult, to see some evidence that the teams were independent in their methods. Something like submitting a hash of their simulation results as they adjust the model parameters would be interesting, or maybe there is a fancier way I'm not aware of.
   11mo ago
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