Bitcoin Wiki - User contributions [en]

Pooled mining

2016-07-19T18:27:44Z

Crackers: /* References */

'''Pooled mining''' is a [[Mining|mining]] approach where multiple generating clients contribute to the generation of a block, and then split the block reward according the contributed processing power. Pooled mining effectively reduces the granularity of the block generation reward, spreading it out more smoothly over time.

==Introduction==

With increasing generation difficulty, mining with lower-performance devices can take a very long time before block generation, on average. For example, with a mining speed of 1000 Khps, at a difficulty of 14484 (which was in effect at the end of December, 2010), the average time to generate a block is almost 2 years.

To provide a more smooth incentive to lower-performance miners, several pooled miners, using different approaches, have been created. With a mining pool, a lot of different people contribute to generating a block, and the reward is then split among them according to their processing contribution. This way, instead of waiting for years to generate 50btc{{Citation needed}} in a block, a smaller miner may get a fraction of a Bitcoin on a more regular basis.

A '''share''' is awarded by the mining pool to the clients who present a valid [[proof of work]] of the same type as the proof of work that is used for creating [[block|blocks]], but of lesser difficulty, so that it requires less time on average to generate.

==Pooled mining approaches==

The problem with pooled mining is that steps must be taken to prevent cheating by the clients and the server. Currently there are several different approaches used.

===The slush approach===

[[Bitcoin Pooled Mining]] (BPM), sometimes referred to as "slush's pool", follows a score-based method. Older shares (from beginning of the round) have lower weight than more recent shares, which reduces the motivation to cheat by switching between pools within a round.

===The Pay-per-Share approach===

The Pay-per-Share (PPS) approach, first described by [[BitPenny]], is to offer an instant flat payout for each share that is solved. The payout is offered from the pool's existing balance and can therefore be withdrawn immediately, without waiting for a block to be solved or confirmed. The possibility of cheating the miners by the pool operator and by timing attacks is thus completely eliminated.

This method results in the least possible variance for miners while transferring all risk to the pool operator. The resulting possibility of loss for the server is offset by setting a payout lower than the full expected value.

===Luke-Jr's approach ("[[Eligius]]")===
[[User:Luke-Jr|Luke]] came up with a third approach borrowing strengths from the earlier two.
Like slush's approach, miners submit proofs-of-work to earn shares.
Like puddinpop's approach, the pool pays out immediately via block generation.
When distributing block rewards, it is divided equally among all shares since the last valid block.
Unlike any preexisting pool approach, this means that the shares contributed toward stale blocks are recycled into the next block's shares.
In order to spare participating miners from transaction fees, rewards are only paid out if a miner has earned at least 0.67108864 BTC (400 [[Tonal Bitcoin|TBC]]). If the amount owed is less, it will be added to the earnings of a later block (which may then total over the threshold amount).
If a miner does not submit a share for over a week, the pool sends any balance remaining, regardless of its size.

===P2Pool approach===

[[P2Pool]] mining nodes work on a chain of shares similar to Bitcoin’s blockchain. When a block is found, the reward is divided among the most recent shares in this share-blockchain. Like the puddinpop and Luke-Jr approaches, p2pool pays via generation.

===Comparison===

The cooperative mining approach (slush and Luke-Jr) uses a lot less resources on the pool server, since rather than continuously checking metahashes, all that has to be checked is the validity of submitted shares. The number of shares sent can be adjusted by adjusting the artificial difficulty level.

Further, the cooperative mining approach allows the clients to use existing miners without any modification, while the puddinpop approach requires the custom pool miner, which are as of now not as efficient on GPU mining as the existing GPU miners.
[[File:Smallgeneration.png|thumb|Puddinpop miners receive coins directly.]]

Additionally, the puddinpop and Luke-Jr approaches of distributing the earnings by way of including precise sub-cent amounts in the generation transaction for the participants, results in the presence of sub-cent bitcoin amounts in your wallet, which are liable to disappear (as unnecessary fees) later due to a bug in old (before 0.3.21) bitcoin nodes. (E.g., if you have a transaction with 0.052 in your wallet, and you later send .05 to someone, your .002 will disappear.).

Puddinpop and Luke-Jr miners receive coins directly, which eliminates the delay in receiving earnings that is required on slush-based mining servers. However, using some [[eWallet]] services for generated coin will cause those coins to be lost.

==See Also==

* [[:Category:Miners|Miners]]
* [[Poolservers]]
* [[Comparison of mining pools]]
* [[:Category:Pool Operators|Pool Operators]]
* [[Why a GPU mines faster than a CPU]]
* [[Why pooled mining]]
* [[Mining pool reward FAQ]]

==External links==

* [http://www.bitcoin.org/smf/index.php?topic=1458.0 puddinpop's mining pool thread]
* [http://blockexplorer.com/block/00000000000233334b157d901714baf59e5b9236227b2878844e52244da4195e example puddinpop block]

==References==
<references />

* [https://www.zpool.ca/ Bitcoin Multipool]
* [https://www.bitcoinmining.com/ Bitcoin Mining]
* [https://www.youtube.com/watch?v=GmOzih6I1zs Video: What is Bitcoin Mining]
* [http://bitcoinminer.com Bitcoin Miner]

[[ru:майнинг в пулах]]
[[Category:Mining]]
{{Pools}}

Mining

2016-07-19T18:26:28Z

Crackers: /* See Also */

[[File:Quick-and-dirty-4x5970-cooling.jpg|thumb|right|A quick and dirty mining rig]]
== Introduction ==
'''Mining''' is the process of adding transaction records to Bitcoin's public ledger of past transactions.
This ledger of past transactions is called the [[block chain]] as it is a chain of [[block|blocks]].
The block chain serves to [[Confirmation|confirm]] transactions to the rest of the network as having taken place.
Bitcoin nodes use the block chain to distinguish legitimate Bitcoin transactions from attempts to re-spend coins that have already been spent elsewhere.

Mining is intentionally designed to be resource-intensive and difficult so that the number of blocks found each day by miners remains steady. Individual [[blocks]] must contain a [[proof of work|proof of work]] to be considered valid. This proof of work is verified by other Bitcoin nodes each time they receive a block. Bitcoin uses the [[hashcash]] proof-of-work function.

The primary purpose of mining is to allow Bitcoin nodes to reach a secure, tamper-resistant consensus.
Mining is also the mechanism used to introduce Bitcoins into the system:
Miners are paid any transaction fees as well as a "subsidy" of newly created coins.
This both serves the purpose of disseminating new coins in a decentralized manner as well as motivating people to provide security for the system.

Bitcoin mining is so called because it resembles the mining of other commodities:
it requires exertion and it slowly makes new currency available at a rate that resembles the rate at which commodities like gold are mined from the ground.

== Difficulty ==
=== The Computationally-Difficult Problem ===
Mining a block is difficult because the SHA-256 hash of a block's header must be lower than or equal to the [[Target|target]] in order for the block to be accepted by the network. This problem can be simplified for explanation purposes: The hash of a block must start with a certain number of zeros. The probability of calculating a hash that starts with many zeros is very low, therefore many attempts must be made. In order to generate a new hash each round, a [[Nonce|nonce]] is incremented. See [[Proof of work]] for more information.

=== The Difficulty Metric ===
The [[Difficulty|difficulty]] is the measure of how difficult it is to find a new block compared to the easiest it can ever be. It is recalculated every 2016 blocks to a value such that the previous 2016 blocks would have been generated in exactly two weeks had everyone been mining at this difficulty. This will yield, on average, one block every ten minutes. As more miners join, the rate of block creation will go up. As the rate of block generation goes up, the difficulty rises to compensate which will push the rate of block creation back down. Any blocks released by malicious miners that do not meet the required difficulty [[Target|target]] will simply be rejected by everyone on the network and thus will be worthless.

=== Reward ===
When a block is discovered, the discoverer may award themselves a certain number of bitcoins, which is agreed-upon by everyone in the network. Currently this bounty is 25 bitcoins; this value will halve every 210,000 blocks. See [[Controlled Currency Supply]].

Additionally, the miner is awarded the fees paid by users sending transactions. The fee is an incentive for the miner to include the transaction in their block. In the future, as the number of new bitcoins miners are allowed to create in each block dwindles, the fees will make up a much more important percentage of mining income.

== The mining ecosystem ==

=== Hardware ===
[[File:Usb-fpga module 1.15x-hs-800.jpg|thumb|right|FPGA Module]]
Users have used various types of hardware over time to mine blocks. Hardware specifications and performance statistics are detailed on the [[Mining Hardware Comparison]] page.
==== CPU Mining ====
Early Bitcoin client versions allowed users to use their CPUs to mine. The advent of GPU mining made CPU mining financially unwise as the hashrate of the network grew to such a degree that the amount of bitcoins produced by CPU mining became lower than the cost of power to operate a CPU. The option was therefore removed from the core Bitcoin client's user interface.

==== GPU Mining ====
GPU Mining is drastically faster and more efficient than CPU mining. See the main article: [[Why a GPU mines faster than a CPU]]. A variety of popular [[Mining rig|mining rigs]] have been documented.
==== FPGA Mining ====
FPGA mining is a very efficient and fast way to mine, comparable to GPU mining and drastically outperforming CPU mining. FPGAs typically consume very small amounts of power with relatively high hash ratings, making them more viable and efficient than GPU mining. See [[Mining Hardware Comparison]] for FPGA hardware specifications and statistics.
==== ASIC Mining ====
An application-specific integrated circuit, or ''ASIC'', is a microchip designed and manufactured for a very specific purpose. ASICs designed for Bitcoin mining were first released in 2013. For the amount of power they consume, they are vastly faster than all previous technologies and already have made GPU mining financially unwise in some countries and setups.

==== Mining services (Cloud mining) ====
[[:Category:Mining_contractors|Mining contractors]] provide mining services with performance specified by contract, often referred to as a "Mining Contract". They may, for example, rent out a specific level of mining capacity for a set price for a specific duration.

=== Pools ===
As more and more miners competed for the limited supply of blocks, individuals found that they were working for months without finding a block and receiving any reward for their mining efforts. This made mining something of a gamble. To address the variance in their income miners started organizing themselves into [[Pooled mining|pools]] so that they could share rewards more evenly. See [[Pooled mining]] and [[Comparison of mining pools]].

=== History ===
Bitcoin's public ledger (the 'block chain') was started on January 3rd, 2009 at 18:15 UTC presumably by [[Satoshi Nakamoto]]. The first block is known as the [[genesis block]]. The first transaction recorded in the first block was a single transaction paying the reward of 50 new bitcoins to its creator.

==See Also==

* [https://www.zpool.ca Bitcoin Multipool]
* [https://www.bitcoinmining.com Bitcoin Mining]
* [http://codinginmysleep.com/bitcoin-mining-in-plain-english Bitcoin Mining in Plain English] by David Perry
* [https://www.weusecoins.com/en/mining-guide/ Getting Started With Bitcoin Mining]
* [[Automatically mine when computer is locked|Tutorial to automatically start mining when you lock your computer]]. (Windows 7)
* [http://bitcoinminer.com Bitcoin Miner]
* [http://www.reddit.com/r/Bitcoin/comments/18q2jx/eli5_bitcoin_mining_xpost_in_eli5/ Simplified Explanation of Bitcoin Mining] by reddit user [http://www.reddit.com/user/azotic azotic]
* [https://bitcoinchain.com/pools Bitcoin Mining Pools Comparison]
* [http://www.bitcoinmining.com/best-bitcoin-cloud-mining-contract-reviews/ Research, Review and Compare Cloud Mining Contracts]
* [https://www.youtube.com/watch?v=GmOzih6I1zs Video: What is Bitcoin Mining?]
* [http://yogh.io/#mine:last Mining Simulator] ([https://github.com/JornC/bitcoin-transaction-explorer GitHub source])
* [http://bitcoindaily.org/bitcoin-guides/what-is-bitcoin-mining/ Bitcoin Mining Explained]
[[ru:Mining]]
[[Category:Mining]][[Category:Vocabulary]]

Transaction broadcasting

2015-12-11T18:41:53Z

Crackers: /* See Also */

{{seealso|Satoshi Client Transaction Exchange}}

==See Also==

Third party sites to (re-)submit a raw, signed transaction to the network; sometimes referred to as "pushtx":

* https://armory.online/tx/send (site is in development)
* https://insight.bitpay.com/tx/send
* https://blockchain.info/pushtx
* https://blockexplorer.com/tx/send
* https://btc.blockr.io/tx/push
* https://coinb.in/#broadcast
* https://chain.localbitcoins.com/tx/send
* http://webbtc.com/relay_tx
* https://www.smartbit.com.au/txs/pushtx
* https://live.blockcypher.com/btc/pushtx/
* https://helloblock.io/propagate
* https://www.f2pool.com/pushtx (Needs referral code from pool operator.)
* https://wallet.la/pushtx

Currently defunct:

* <ref>Messages following: https://bitcointalk.org/index.php?topic=441465.msg10027173#msg10027173</ref> http://eligius.st/~wizkid057/newstats/pushtxn.php (Contact wizkid057 directly if you need a transaction mined.)
* https://search.bitaccess.ca

==References==

Transaction broadcasting

2015-12-11T18:40:52Z

Crackers: /* See Also */

{{seealso|Satoshi Client Transaction Exchange}}

==See Also==

Third party sites to (re-)submit a raw, signed transaction to the network; sometimes referred to as "pushtx":

* https://armory.online/tx/send (site is in development)
* https://insight.bitpay.com/tx/send
* https://blockchain.info/pushtx
* https://blockexplorer.com/tx/send
* https://btc.blockr.io/tx/push
* https://coinb.in/#broadcast
* https://chain.localbitcoins.com/tx/send
* http://webbtc.com/relay_tx
* https://www.smartbit.com.au/txs/pushtx
* https://live.blockcypher.com/btc/pushtx/
* https://www.f2pool.com/pushtx (Needs referral code from pool operator.)
* https://wallet.la/pushtx

Currently defunct:

* <ref>Messages following: https://bitcointalk.org/index.php?topic=441465.msg10027173#msg10027173</ref> http://eligius.st/~wizkid057/newstats/pushtxn.php (Contact wizkid057 directly if you need a transaction mined.)
* https://search.bitaccess.ca

==References==

Transaction broadcasting

2015-11-30T03:53:57Z

Crackers:

{{seealso|Satoshi Client Transaction Exchange}}

==See Also==

Third party sites to (re-)submit a raw, signed transaction to the network; sometimes referred to as "pushtx":

* https://armory.online/tx/send (site is in development)
* https://insight.bitpay.com/tx/send
* https://blockchain.info/pushtx
* https://blockexplorer.com/tx/send
* https://btc.blockr.io/tx/push
* https://coinb.in/#broadcast
* https://www.f2pool.com/pushtx (Needs referral code from pool operator.)
* https://chain.localbitcoins.com/tx/send
* https://wallet.la/pushtx
* http://webbtc.com/relay_tx
* https://www.smartbit.com.au/txs/pushtx

Currently defunct:

* <ref>Messages following: https://bitcointalk.org/index.php?topic=441465.msg10027173#msg10027173</ref> http://eligius.st/~wizkid057/newstats/pushtxn.php (Contact wizkid057 directly if you need a transaction mined.)
* https://search.bitaccess.ca

==References==