I apologize if this discussion should be moved to -discuss, I'll let the moderators decide, I've copied both.

And Gavin, I apologize for picking on you here, because certainly this carelessness in how people represent "facts" applies to both sides, but much of this discussion really infuriates me.
I believe it is completely irresponsible for you to state:
"There will be approximately zero percentage of hash power left on the weaker branch of the fork, based on past soft-fork adoption by miners"
Sure, the rest of the technical community is capable of evaluating that for themselves, but your statements are considered authoritative by much larger audience.  In truth, no one has any idea what would happen if the proposed Classic hard fork activated with 75% right now.  There is some chance you are right, but there is a very legitimate possibility that a concerted effort would arise to maintain a minority fork or perhaps if miners don't see nearly a complete switch over, many of them might themselves reverse the fork if they think it would be easier to achieve consensus that way.  We as a community have never been in such a situation before and it behooves us to speak honestly and directly about the uncertainty of the situation.

And the back and forth discussion over your BIP has been in large part a charade.  People asking why you aren't picking 95% know very well why you aren't, but lets have an honest discussion of what the risks and in your mind potential benefits of 75% are.   Important debate about parameters of your BIP get lost because we're sniping at each other about known disagreements.  For instance, I strongly believe 28 days is far too short.  I think its extremely unlikely that those who are opposed to a contentious hard fork will do the development work to prepare for it as that may only make it more likely to happen.  Thus if you did achieve activation with 75%, its almost impossible to imagine that if Bitcoin Core decided to come along (as opposed to pursuing a minority fork) that they'd have the time to develop and test the patch and roll it out to wide adoption.   If the goal of your attempt is that any minority that disagreed will "choose" to follow the majority branch, then you'd be much more likely to achieve that by giving them time to decide that's what they wanted and roll out the software to do so.




On Sun, Feb 7, 2016 at 9:16 AM, Gavin Andresen via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
On Sat, Feb 6, 2016 at 3:46 PM, Luke Dashjr via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
On Saturday, February 06, 2016 5:25:21 PM Tom Zander via bitcoin-dev wrote:
> On Saturday, February 06, 2016 06:09:21 PM Jorge Timón via bitcoin-dev
wrote:
> > None of the reasons you list say anything about the fact that "being
> > lost" (kicked out of the network) is a problem for those node's users.
>
> That's because its not.
>
> If you have a node that is "old" your node will stop getting new blocks.
> The node will essentially just say "x-hours behind" with "x" getting larger
> every hour. Funds don't get confirmed. etc.

Until someone decides to attack you. Then you'll get 6, 10, maybe more blocks
confirming a large 10000 BTC payment. If you're just a normal end user (or
perhaps an automated system), you'll figure that payment is good and
irreversibly hand over the title to the house.

There will be approximately zero percentage of hash power left on the weaker branch of the fork, based on past soft-fork adoption by miners (they upgrade VERY quickly from 75% to over 95%).

So it will take a week to get 6 confirmations.

If you are a full node, you are warned that your software is obsolete and you must upgrade.

If you are a lightweight node, it SHOULD tell you something is wrong, but even if it doesn't, given that people running lightweight nodes run them so they don't have to be connected to the network 24/7, it is very likely during that week you disconnect and reconnect to the network several times. And every time you do that you increase your chances that you will connect to full nodes on the majority branch of the chain, where you will be told about the double-spend.

All of that is assuming that there is no OTHER mitigation done. DNS seeds should avoid reporting nodes that look like they are in the middle of initial block download (that are at a block height significantly behind the rest of the network), for example.

--
--
Gavin Andresen


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