91

Merged mining allows a miner to mine for more than one block chain at the same time. The benefit is that every hash the miner does contributes to the total hash rate of both (all) currencies, and as a result they are all more secure. Starting with a high-level explanation: The miner (or mining controller in the case of pooled mining) actually builds a block ...


29

Basically the idea is that you assemble a Namecoin block and hash it, and then insert that hash into a Bitcoin block. Now when you solve the Bitcoin block at a difficulty level greater to or equal to the Namecoin difficulty level, it will be proof that that amount of work has been done for the Namecoin block. The Namecoin protocol has been altered to ...


13

Yes. The ASICs themselves only perform the SHA256 calculations, they do not deal with anything protocol related and as such can merged-mine exactly the same as existing GPU and FPGA implementations. In other words, merged mining is part of the protocol, ASICs just do the math. The standard rules of merged mining still apply, of course. The alternate ...


13

Namecoins are used to register .bit domains: http://dot-bit.org/HowToRegisterAndConfigureBitDomains They're also bought and sold by speculators, but DNS registration is their original purpose.


12

The switch to merged mining is scheduled for Namecoin block 19200. At the time of this writing, the Namecoin network is on block 18805, so 395 more blocks need to be solved. The last 29 blocks on the Namecoin block explorer were solved in an average of 108.79 minutes each. Extrapolating from this, 395 blocks should be solved in just under 30 days, so ...


12

Every hash you do will contribute fully to the hashing power of both block chains. You will have to do a tiny bit of extra work when you generate a work unit, but that's almost insignificant, and you only need to generate a work unit once for every few billion hashes you do. You will generate just as many Bitcoins as if you only mined Bitcoins and just as ...


8

Those running a miner against a pool don't. The pool operator would need both. As stated in the comments below, normal users of the alternate system will not need the bitcoin chain but will need the alternate chain, and normal users of bitcoin will need the bitcoin chain but not the alternate chain. Once the block is mined, nobody cares what other chains ...


8

The only way to know for sure would be if you mined for the pool and you mined a Namecoin block for them. You would find the particular header you had submitted as a share used as a solved, merge-mined Namecoin block.


8

As Mikka explains, sidechains don't need to create their own currency, using bitcoins in the sidechain is precisely the point of two-way peg (there's no reason why an altchain with its own currency, like say litecoin or ethereum, couldn't support 2-way peg and also become a sidechain though). Also, take into account there's several possible ways to implement ...


6

Satoshi himself seems to be the inventor of merged mining. In his words (bitcointalk.org): I think it would be possible for BitDNS to be a completely separate network and separate block chain, yet share CPU power with Bitcoin. The only overlap is to make it so miners can search for proof-of-work for both networks simultaneously. The networks wouldn'...


5

The patch has no effect on the parent blockchain, it just allows the patched bitcoind to be used for mining on both chains simultaneously. Only the child blockchain needs to be modified in order to support merged mining. There's no way for the Bitcoin network to prevent merged mining, even if doing so were desirable. Merged mining does have to potential ...


5

NameCoin merged mining adds no more than 49 bytes to the size of the block. Namecoin messages aren't stored in the bitcoin block chain, instead the hash of the most recent namecoin block is stored in the Bitcoin block providing continuity between a potential hash and the Namecoin block chain. So yes it technically does "bloat" the Bitcoin blockchain but ...


5

Found a helpful post at litecointalk: It won't work because the aux work must be explicitly provided by the merge coin. All of these coins cloned from Litecoin lack that code as Litecoin doesn't have it. As a result you cannot merge mine these coins. It is the same reason you can't merge mine Terracoin or Freicoin with Bitcoin. Freicoin considered ...


4

A 44-byte header cointaining: magic: 0xfa, 0xbe, 'm', 'm' (only required if over 20 bytes past the start of the script; optional otherwise) block_hash: Hash of the Namecoin block header merkle_size: Number of entries in aux work merkle tree. merkle_nonce: Nonce used to calculate indexes into aux work merkle tree; you may as well leave this at zero is ...


4

There's actually a very good detailed specification on the bitcoin.it site. Essentially, what it comes down to is that there's some data inserted into the coinbase transaction of the parent chain. So, assuming, for example, that Bitcoin is the parent chain and Namecoin the child chain, anyone merge-mining would be using a coinbase transaction in Bitcoin ...


3

The disadvantage of merged mining is the additional coin daemons you have to run in the background. They all use disk space, memory, cpu cycles and bandwidth. A more annoying issue is that most of them are no longer maintained and have bugs. You may find that they crash frequently - at least namecoind does.


3

Yes, block 19200 was mined using MM, by slush's pool. AFAIK first Bitcoin block with merged-mining information was 00000000000002c727047296ee20b628599031c6ea5c09292513fddbb11d34df (block 148557), also mined by slush's pool.


3

Functionality of merged mining for reference, from user ttk2 on BitcoinTalk: "Merged mining works like this, you have two totally separate block chains, they are not related in any way nor does either contain any data from the other. When you mine you generate hashes that may be the solution to the current block, this is very very improbable per hash, its ...


3

one thing to remember in merged mining is that the block hash of the auxiliary chain (eg namecoin) does not need to be below the aux-chain threshold. rather, it is the block hash of the parent (eg bitcoin) which must be below the aux-chain (namecoin) threshold. for example, check out what happened to namecoin when merged mining was introduced in block 19200: ...


3

A side chain is a blockchain that runs parallel to the main bitcoin blockchain and can synchronize with it directly, allowing decentralized value transfer between the two chains. A user is able to essentially lock up a certain amount of coin on the main bitcoin block chain which then frees up an equivalent amount of coin on the side chain. This side chain ...


3

The point of mining is to secure the blockchain. Before you mine, you must compose the block you are trying to find a nonce for. That block will include a transaction to pay you. If you are merged mining Bitcoin and Namecoin, you do the following: 1) You compose the Namecoin block you are trying to find a nonce for. This includes a transaction to pay you ...


3

You may want to take a look at this GitHub repo, which supports merged mining.


2

Your question seems to be based on a misunderstanding. The patch simply allows you to do merged mining. It doesn't add support for other people to do merged mining to Bitcoin, as that is not necessary. Anything placed in the Bitcoin hash chain will be secured by the Bitcoin mining process. If I put "HAVE A NICE DAY" into a transaction, as Eligius puts ...


2

AFAIK the upcoming patch is for merged mining between Namecoin and Bitcoin only. In the future it might be able to modify the patch to allow more generalized merged mining between any number of coins. This is not a bad thing Quote from Gavin in the thread you linked to: I don't see how shared mining dilutes bitcoins. That's like saying "real-world ...


2

You will need to be running the standard client with some special configuration - server=1 along with rpcuser and rpcpassword set. After that, you need to build your pool server to communicate with it through Bitcoin API and handle everything else. Last part is not too Bitcoin-specific and will consume a lot of your development time (I would know, I tried it ...


2

with p2pool at least for the coins are 'merged' mining you cannot reconfigure them to go to any other account except for the default account of that wallet. However you may be able to work around this in one of the following ways depending on your coding ability. Monitor P2Pool logs and trigger script Watch the p2pool logs and when a block is found ...


2

Most of what you need is explained at https://en.bitcoin.it/wiki/Merged_mining_specification When you construct the block for the primary chain (e.g. bitcoin) you need to include a merged mining header in the generation transaction (coinbase). The format of this data is explained at the URL above under "Merged mining coinbase". If, while hashing the ...


2

If you fake the bitcoin blocks, then you will be mining only namecoins and no bitcoins, so you are losing 99% of your mining income. You can't just mine at a height above the current namecoin blockchain. Remember that it is a chain. Each block has to link to the previous one. If you want to mine at namecoin height X which is thousands of blocks above the ...


2

You actually don't use the addresses, but the RPC info for the daemons. For example you'd start the pool with the following switches: python run_p2pool.py --net vertcoin3 --merged http://*RPCuser1*:*LongRPCpass1*@127.0.0.1:6888 --merged http://*RPCuser2*:*LongRPCpass*2@127.0.0.1:7817 You will see "Got new merged mining work!" in console as confirmation.


2

You verify the auxiliary chain precisely the same way, except you must also check that the auxiliary chain's header is properly included in the parent's coinbase. From the point of view of the auxiliary chain, you can think of the entire primary chain header as part of a giant nonce.


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