Understand the fundamentals
Why many miners work together
A single miner working alone can wait a very long time to find a block. A mining pool is a service that combines the work of many miners. It shares out the revenue according to its payout rules. Pooling changes how the uncertainty of finding blocks is shared. It does not remove the need to do proof of work.
The pool sends jobs to each miner. A job holds the information the miner needs to build candidate block headers to try. A worker name is a label. It tells the pool which machine, or group of machines, did the work and which account to credit. It is not the miner’s IP address (network address), serial number or Bitcoin payout address. However, a site may build a location or asset number into the label.
See how it works
A share is evidence, not usually a block
The pool sets its own target, which is easier to meet than Bitcoin’s network target. Miners send the pool each result that meets the pool target. These results are called shares. Shares are evidence of the computing work each miner has done. Very rarely, a share also meets the network target. Then the pool can submit the block built from it to the network, where nodes check it. Most accepted shares meet only the pool target.
Accepted means the pool counted the share under its rules. Stale usually means the share arrived too late, after the pool had moved on to a newer job. A pool can also reject a share for other reasons. It may be a duplicate, it may not meet the pool target, or there may be a settings or communication problem. The reason matters. A rejected-share count alone cannot prove that a hashboard (a board of mining chips) is bad.
Visual explanation
One result can meet two different thresholds
- Result 500
- Above both example targets, so it does not qualify as a share.
- Result 70
- Meets an example pool target of 99, but not an example network target of 9.
- Result 3
- Meets both example targets. The block built from it must still pass every other Bitcoin rule.
These small numbers only show the idea. They are not real Bitcoin targets, and the real gap between the two targets is different. A lower target is harder to meet.
| Result | Meaning | Does not prove |
|---|---|---|
| Local hash calculation | Work performed inside the machine | That the pool received it |
| Accepted share | Work credited under pool rules | That a Bitcoin block was found |
| Network-target result | May support a valid block proposal | That invalid transactions become valid |
| Rejected submission | Not counted under the pool’s rules | That the hardware is faulty |
Connect it to the field
Understand the numbers before discussing payment
Pools estimate each miner’s contribution from its accepted work over time. Each share has a difficulty, and a higher-difficulty share stands for more work. Share difficulty can change from machine to machine and over time. So two raw share counts cannot be compared directly. Pools also pay in different ways. Some pay for contributed work under stated terms. Others depend more directly on the blocks the pool finds. Fees, payout thresholds and timing follow each pool’s current policy.
For example, the miner’s own dashboard may show its chips working while the pool shows no work for the expected worker. Before you decide the hardware failed, check that you are looking at the right account, worker name and time period. Your evidence should show where the work is being reported. It should not promise earnings based on a single screenshot.
Terms used in this lesson
- Pool
- A service that combines many miners’ work and keeps track of what each one contributes.
- Share
- A result that meets the pool’s target and is sent to the pool.
- Block candidate
- A proposed block that miners are hashing. It becomes a valid block only if its hash meets the network’s harder target and the block passes every other rule.
Optional references & further reading
Use current manufacturer instructions for the exact equipment and your site’s approved procedures. Course levels do not grant task authorization.