They do so by not building on larger blocks On Jun 23, 2015 9:31 PM, "Raystonn" wrote: > No, they can lower their own block sizes. But they cannot currently lower > the sizes of blocks mined by others. That is not the same thing by any > stretch of the imagination. > On 23 Jun 2015 8:50 pm, Jeff Garzik wrote: > > Miners can collude today to lower the block size limit. > > In fact, this largely happens already out of laziness - miners often > follow the "soft" default limit set by Bitcoin Core, to the point where you > can chart when miners upgrade to new software: > http://hashingit.com/analysis/39-the-myth-of-the-megabyte-bitcoin-block > > > > On Tue, Jun 23, 2015 at 8:05 PM, William Madden > wrote: > > Here are refutations of the approach in BIP-100 here: > http://gtf.org/garzik/bitcoin/BIP100-blocksizechangeproposal.pdf > > To recap BIP-100: > > 1) Hard form to remove static 1MB block size limit > 2) Add new floating block size limit set to 1MB > 3) Historical 32MB message limit remains > 4) Hard form on testnet 9/1/2015 > 5) Hard form on main 1/11/2016 > 6) 1MB limit changed via one-way lock in upgrade with a 12,000 block > threshold by 90% of blocks > 7) Limit increase or decrease may not exceed 2x in any one step > 8) Miners vote by encoding 'BV'+BlockSizeRequestValue into coinbase > scriptSig, e.g. "/BV8000000/" to vote for 8M. > 9) Votes are evaluated by dropping bottom 20% and top 20%, and then the > most common floor (minimum) is chosen. > > 8MB limits doubling just under every 2 years makes a static value grow > in a predictable manner. > > BIP-100 makes a static value grow (or more importantly potentially > shrink) in an unpredictable manner based on voting mechanics that are > untested in this capacity in the bitcoin network. Introducing a highly > variable and untested dynamic into an already complex system is > unnecessarily risky. > > For example, the largely arbitrary voting rules listed in 9 above can be > gamed. If I control pools or have affiliates involved in pools that > mine slightly more than 20% of blocks, I could wait until block sizes > are 10MB, and then suddenly vote "/BV5000000/" for 20% of blocks and > "/BV5000001/" for the remaining 10%. If others don't consistently vote > for the same "/BV#/" value, vote too consistently and have their value > thrown out as the top 20%, I could win the resize to half capacity > "/BV5000001/" because it was the lowest repeated value not in the bottom > 20%. > > I could use this to force an exodus to my sidechain/alt coin, or to > choke out the bitcoin network. A first improvement would be to only let > BIP-100 raise the cap and not lower it, but if I can think of a > vulnerability off the top of my head, there will be others on the other > side of the equation that have not been thought of. Why bother > introducing a rube goldberg machine like voting when a simple 8mb cap > with predictable growth gets the job done, potentially permanently? > > > On 6/23/2015 9:43 PM, odinn wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > 1) Hard fork not (necessarily) needed > > 2) See Garzik's BIP 100, better (this is not meant to say "superior to > > your stuff," but rather simply to say, "Better you should work with > > Garzik to implement BIP-100, that would be good") > > 3) See points 1 and 2 above > > 4) If still reading... changes should be (as you seem to have been > > trying to lean towards)... lean towards gradual change; hence, changes > > that would flow from this BIP would be better off oriented in a > > process that dies not require the "way you have done it." > > > > You did address that, to be fair - in your TODO, this link: > > http://gavinandresen.ninja/time-to-roll-out-bigger-blocks > > > > contained the following link: > > > > http://gavinandresen.ninja/bigger-blocks-another-way > > > > However, in reading that, I didn't see any meaningful statements that > > would refute the approach in Garzik's BIP-100. > > > > Maybe a better way to say this is, > > > > Work with Jeff Garzik (which I am sure you are already having such > > discussions in private) as well as the list discussions, > > Move forward on BIP-100 with Garzik and other developers (not such a > > bad plan really) and don't get caught up in XT. (If you feel you can > > develop XT further, that is your thing but it would perhaps make you > > lose focus, work together with other developers.) > > > > Relax into the process. Things will be ok. > > > > Respectfully, > > > > - -O > > > > On 06/22/2015 11:18 AM, Gavin Andresen wrote: > >> I promised to write a BIP after I'd implemented > >> increase-the-maximum-block-size code, so here it is. It also lives > >> at: > >> https://github.com/gavinandresen/bips/blob/blocksize/bip-8MB.mediawiki > >> > >> I don't expect any proposal to please everybody; there are > >> unavoidable tradeoffs to increasing the maximum block size. I > >> prioritize implementation simplicity -- it is hard to write > >> consensus-critical code, so simpler is better. > >> > >> > >> > >> > >> BIP: ?? Title: Increase Maximum Block Size Author: Gavin Andresen > >> > Status: > >> Draft Type: Standards Track Created: 2015-06-22 > >> > >> ==Abstract== > >> > >> This BIP proposes replacing the fixed one megabyte maximum block > >> size with a maximum size that grows over time at a predictable > >> rate. > >> > >> ==Motivation== > >> > >> Transaction volume on the Bitcoin network has been growing, and > >> will soon reach the one-megabyte-every-ten-minutes limit imposed by > >> the one megabyte maximum block size. Increasing the maximum size > >> reduces the impact of that limit on Bitcoin adoption and growth. > >> > >> ==Specification== > >> > >> After deployment on the network (see the Deployment section for > >> details), the maximum allowed size of a block on the main network > >> shall be calculated based on the timestamp in the block header. > >> > >> The maximum size shall be 8,000,000 bytes at a timestamp of > >> 2016-01-11 00:00:00 UTC (timestamp 1452470400), and shall double > >> every 63,072,000 seconds (two years, ignoring leap years), until > >> 2036-01-06 00:00:00 UTC (timestamp 2083190400). The maximum size of > >> blocks in between doublings will increase linearly based on the > >> block's timestamp. The maximum size of blocks after 2036-01-06 > >> 00:00:00 UTC shall be 8,192,000,000 bytes. > >> > >> Expressed in pseudo-code, using integer math: > >> > >> function max_block_size(block_timestamp): > >> > >> time_start = 1452470400 time_double = 60*60*24*365*2 size_start = > >> 8000000 if block_timestamp >= time_start+time_double*10 return > >> size_start * 2^10 > >> > >> // Piecewise-linear-between-doublings growth: time_delta = > >> block_timestamp - t_start doublings = time_delta / time_double > >> remainder = time_delta % time_double interpolate = (size_start * > >> 2^doublings * remainder) / time_double max_size = size_start * > >> 2^doublings + interpolate > >> > >> return max_size > >> > >> ==Deployment== > >> > >> Deployment shall be controlled by hash-power supermajority vote > >> (similar to the technique used in BIP34), but the earliest possible > >> activation time is 2016-01-11 00:00:00 UTC. > >> > >> Activation is achieved when 750 of 1,000 consecutive blocks in the > >> best chain have a version number with bits 3 and 14 set (0x20000004 > >> in hex). The activation time will be the timestamp of the 750'th > >> block plus a two week (1,209,600 second) grace period to give any > >> remaining miners or services time to upgrade to support larger > >> blocks. If a supermajority is achieved more than two weeks before > >> 2016-01-11 00:00:00 UTC, the activation time will be 2016-01-11 > >> 00:00:00 UTC. > >> > >> Block version numbers are used only for activation; once activation > >> is achieved, the maximum block size shall be as described in the > >> specification section, regardless of the version number of the > >> block. > >> > >> > >> ==Rationale== > >> > >> The initial size of 8,000,000 bytes was chosen after testing the > >> current reference implementation code with larger block sizes and > >> receiving feedback from miners stuck behind bandwidth-constrained > >> networks (in particular, Chinese miners behind the Great Firewall > >> of China). > >> > >> The doubling interval was chosen based on long-term growth trends > >> for CPU power, storage, and Internet bandwidth. The 20-year limit > >> was chosen because exponential growth cannot continue forever. > >> > >> Calculations are based on timestamps and not blockchain height > >> because a timestamp is part of every block's header. This allows > >> implementations to know a block's maximum size after they have > >> downloaded it's header, but before downloading any transactions. > >> > >> The deployment plan is taken from Jeff Garzik's proposed BIP100 > >> block size increase, and is designed to give miners, merchants, > >> and full-node-running-end-users sufficient time to upgrade to > >> software that supports bigger blocks. A 75% supermajority was > >> chosen so that one large mining pool does not have effective veto > >> power over a blocksize increase. The version number scheme is > >> designed to be compatible with Pieter's Wuille's proposed "Version > >> bits" BIP. > >> > >> TODO: summarize objections/arguments from > >> http://gavinandresen.ninja/time-to-roll-out-bigger-blocks. > >> > >> TODO: describe other proposals and their advantages/disadvantages > >> over this proposal. > >> > >> > >> ==Compatibility== > >> > >> This is a hard-forking change to the Bitcoin protocol; anybody > >> running code that fully validates blocks must upgrade before the > >> activation time or they will risk rejecting a chain containing > >> larger-than-one-megabyte blocks. > >> > >> Simplified Payment Verification software is not affected, unless > >> it makes assumptions about the maximum depth of a transaction's > >> merkle branch based on the minimum size of a transaction and the > >> maximum block size. > >> > >> ==Implementation== > >> > >> https://github.com/gavinandresen/bitcoinxt/tree/blocksize_fork > >> > >> > >> > >> _______________________________________________ bitcoin-dev mailing > >> list bitcoin-dev@lists.linuxfoundation.org > >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > >> > > > > - -- > > http://abis.io ~ > > "a protocol concept to enable decentralization > > and expansion of a giving economy, and a new social good" > > https://keybase.io/odinn > > -----BEGIN PGP SIGNATURE----- > > Version: GnuPG v1 > > > > iQEcBAEBAgAGBQJVigtJAAoJEGxwq/inSG8CqZwIAIG3ZQzekfccPxBOMqtim175 > > Crov6hrO9FaIzbLljECpUi60RKuDM/fs09ZJsKKIaJPkB5dlJjs4huc206veAIO+ > > K2h3DmAcA6W/Thk0C2cV3ewv+OiELDOhpeoddBBLPadAfaBGr4l9ltqWLdBtMCmw > > OtmiWstEuXTao9ApgoFOmybdmCjbfrfhejOOHs/pMiSn5xVE60RK4x2HFTFsHfAN > > fZAeLCuwuN2qWMrVrr+cbpCXjEuE1xZG3WEj7ppYoGR+AgF/Y5/U1j7S4PVpk85s > > CgMkpcWvLnBMmSCrllnRZy1Gfrwk36Pg0rXD/l/NNd0/KTpmPSvkX/bCyzFwbzo= > > =ft62 > > -----END PGP SIGNATURE----- > > _______________________________________________ > > 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 > > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > >