Bitcoin Cash hardfork confirmed

November 13 Bitcoin Cash hardfork rumors confirmed by the developers team: here is the fork, the algorithm and mining difficulty details
31 October 2017   2074

Hardfork

The previously announced Bitcoin Cash hardfork is to be held on Monday, November 13, so that the exchanges, wallets and other software need to upgrade before this date.

As the developers team reports, the original Bitcoin Cash “EDA” allowed Bitcoin Cash to survive as a minority chain but produces wild fluctuations of hashrate, that in its turn prevents consistently fast confirmations for users, and radically shifts the coin issuance schedule.

After careful consideration, we have made the decision to implement a proposal from Bitcoin ABC lead developer Amaury Sechet. Our decision to choose one specific proposal was not easy, because Bitcoin Cash has several independent development teams, and there was a great deal of deliberation between developers from the different groups.
 

Bitcoin Cash developers team

As detailed, two impartial and unconnected testing teams were chosen to work on the algorithm: Bitprim and nChain. These teams conducted their tests separately and came to the same conclusion of which algorithm was most appropriate. 

However, not everyone thinks so. Charlie Lee, Litecoin creator, doubted the transparency of the choice made:

Algorithm and mining difficulty

According to the team, the new DAA algorithm seeks to accomplish the following objectives:

  • Adjust difficulty to hash rate to target a mean block interval of 600 seconds
  • Avoid sudden changes in difficulty when hash rate is fairly stable
  • Adjust difficulty rapidly when hash rate changes rapidly
  • Avoid oscillations from feedback between hash rate and difficulty
  • Be resilient to attacks such as timestamp manipulation

As the developers detail, the algorithm is based on a 144-period simple moving average. The difficulty is adjusted each block, based on the amount of work done and the elapsed time of the previous 144 blocks.

To compute the difficulty, the process begins with the three topmost blocks, and the one with the median timestamp of the three is chosen. Then, the process is repeated with blocks 144, 145, and 146 (blocks of 144-146 height less than the current) and a median timestamp block is again chosen from those 3.

​From these 2 blocks roughly 144 blocks apart, W is defined as the amount of work done between the blocks, and T as the elapsed time between the blocks.  A high-low filter is applied so that T has maximum value of 2 days and a minimum value of .5 days.  This prevents difficulty from changing too abruptly. (Normally 144 blocks takes approximately 1 day).

Wn = W * ExpectedBlockTime / T .
G = (2^256 / Wn) - 1

According to the team, this is the difficulty target.  

Activation of the new consensus rules will be done on a median time stamp basis on blocks that occur after timestamp 1510600000, which corresponds to November 13th, 2:06 PM GMT.

Bitmain to Announce New ASIC Chip

BM1397 chip requires less energy and is able to achieve efficiency at 30J / TH
18 February 2019   389

This Monday, the Chinese mining company Bitmain announced the next-generation 7-nm chip codenamed BM1397, which, according to it surpasses its predecessors in performance and energy efficiency and is suitable for mining cryptocurrencies on the SHA256 algorithm, including Bitcoin and Bitcoin Cash.

The BM1397 chip requires less energy and is able to achieve efficiency at 30J / TH, which is “higher by 28.6% than the previous 7-nm chip from Bitmain”, codenamed BM1391.

BM1397 is manufactured using TSMC, a Taiwan-based semiconductor product company, which is one of the leading suppliers in the cryptocurrency mining industry.

The BM1397 chip will be installed in the new ASIC miners of the Antminer S17 and Antminer T17 models, the release of which Bitmain promises to announce later. The company does not provide other details of the updated devices in its message.