My preference is height activation + one step per block (i.e. also height). Height seems KISS.
AFAICT most of the attacks would occur around the already-heavily-watched flag day activation event, in a height based environment, a useful attribute. However I would like to hear from others about possible attacks with the various approaches, before diverging from the default community approach of switch-based-on-time. On Fri, Dec 18, 2015 at 3:10 PM, Jorge Timón <jti...@jtimon.cc> wrote: > Well, if it's not going to be height, I think median time of the previous > block is better than the time of the current one, and would also solve Chun > Wang's concerns. > But as said I prefer to use heights that correspond to diff recalculation > (because that's the window that bip9 will use for the later 95% > confirmation anyway). > On Dec 18, 2015 9:02 PM, "Jeff Garzik" <jgar...@gmail.com> wrote: > >> From a code standpoint, based off height is easy. >> >> My first internal version triggered on block 406,800 (~May 5), and each >> block increased by 20 bytes thereafter. >> >> It was changed to time, because time was the standard used in years past >> for other changes; MTP flag day is more stable than block height. >> >> It is preferred to have a single flag trigger (height or time), rather >> than the more complex trigger-on-time, increment-on-height, but any >> combination of those will work. >> >> Easy to change code back to height-based... >> >> >> >> On Fri, Dec 18, 2015 at 2:52 PM, Jorge Timón < >> bitcoin-dev@lists.linuxfoundation.org> wrote: >> >>> I agree that nHeight is the simplest option and is my preference. >>> Another option is to use the median time from the previous block (thus >>> you know whether or not the next block should start the miner confirmation >>> or not). In fact, if we're going to use bip9 for 95% miner upgrade >>> confirmation, it would be nice to always pick a difficulty retarget block >>> (ie block.nHeight % DifficultyAdjustmentInterval == 0). >>> Actually I would always have an initial height in bip9, for softforks >>> too. >>> I would also use the sign bit as the "hardfork bit" that gets activated >>> for the next diff interval after 95% is reached and a hardfork becomes >>> active (that way even SPV nodes will notice when a softfork or hardfork >>> happens and also be able to tell which one is it). >>> I should update bip99 with all this. And if the 2 mb bump is >>> uncontroversial, maybe I can add that to the timewarp fix and th recovery >>> of the other 2 bits in block.nVersion (given that bip102 doesn't seem to >>> follow bip99's recommendations and doesn't want to give 6 full months as >>> the pre activation grace period). >>> On Dec 18, 2015 8:17 PM, "Chun Wang via bitcoin-dev" < >>> bitcoin-dev@lists.linuxfoundation.org> wrote: >>> >>>> In many BIPs we have seen, include the latest BIP202, it is the block >>>> time that determine the max block size. From from pool's point of >>>> view, it cannot issue a job with a fixed ntime due to the existence of >>>> ntime roll. It is hard to issue a job with the max block size unknown. >>>> For developers, it is also easier to implement if max block size is a >>>> function of block height instead of time. Block height is also much >>>> more simple and elegant than time. >>>> _______________________________________________ >>>> bitcoin-dev mailing list >>>> bitcoin-dev@lists.linuxfoundation.org >>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>>> >>> >>> _______________________________________________ >>> bitcoin-dev mailing list >>> bitcoin-dev@lists.linuxfoundation.org >>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>> >>> >>
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