Mining is the process where miners in a pool try to find a possible solution

to a block. To prove that they are working on a block solution (by

submitting tasks), miners send so-called “**shares**”.

**What is a share?**

A share is a cryptographic signature of a transaction block, a data packet

that contains a potential solution to the block. A share is not suitable for

being added to the cryptographic chain as a separate valid block but is

rather a complex "solution" that is difficult to find.

A share is needed by the mining pool to evaluate the contribution of each

miner to the overall activity of the pool in finding a block and a fair

distribution of rewards. Based on the shares sent by the miner, the pool

builds a chart of the miner’s hashrate, evaluates his contribution to the

block search and defines whether the miner is online.

It is more convenient to analyze the activity of a miner more subtly and

consistently with the help of a share than through found block solutions

which happen too rarely for small miners.

What is the share difficulty?

The share difficulty is equal to a certain number or range of numbers.

Difficulty is measured in hashes (TH/GH/PH). It is usually referred to as PH

(pentahesh), TH (terahesh) or GH (gigahesh).

**1PH=1000TH=1000000GH**

For example, for Ethereum, the share difficulty is 2 G, 4 G, 8 G, or 10 G.

The difficulty of the Ethereum network at the time of writing this article

was 14.34 PH (not to be confused with the network hashrate).

That is, 14.34 PH = 14340 TH = 14340000 GH.

**Let's look at an ideal situation**. Let's say that the pools receive blocks in

an order corresponding to their hashrate: an EMCD with 1 GH/s will find

ten blocks per day while another pool, with 10 GH/s, will find one hundred

blocks per day.

**This only happens with 100% pool luck.**

Pool luck explains how many solutions it takes to find a valid block

compared to the average number of solutions.

If luck is equal to or higher than 100%, this means that the pool needs

fewer solutions than expected for a given difficulty.

In reality, everything can be completely different. Today, a pool with a

hashrate of 1 GH/s may receive 2 blocks, tomorrow, 10 blocks, and the

day after tomorrow, as many as 20 blocks, while the hashrate remains

unchanged.

An ideal situation for the Ethereum network:

if the share difficulty were 14.34 PH, then each share would be a solution

to a blockif the share difficulty were 9.1 PH, then every second share would be a

solution to a blockif the share difficulty were 2.5 PH, then every thousandth share would be

a solution to a block

That is, if the network difficulty is 14.34 PH and the share difficulty on the

pool is, say, 4.2 G, the pool needs to receive 3 million 414 thousand

shares to find a solution to one block. In other words, under ideal

circumstances, after every 3,414,000 shares, the pool will find a block.

Let’s compare with BTC:

1PH=1000TH=1000000GH

For example, for Bitcoin, the share difficulty is 128 K, 8192 K, 16384 K,

and 32768 K. The difficulty of the Bitcoin network at the time of writing this article was

31.25 PH (not to be confused with the hashrate of the network at the

moment). That is, 31.25 PH = 31,250 TH = 32,250,000 GH. Let's say that the pools receive blocks in the order corresponding to their hashrate; an EMCD with 1 PH/s will find ten blocks per day while another pool with 10 PH/s will find one hundred blocks per day.

**Remember that this only happens with 100% pool luck. **In fact, today a

pool with a hashrate of 1 PH/s can get 2 blocks, tomorrow, 10 blocks, and

the day after tomorrow, as many as 20 blocks, while the hashrate remains

unchanged.

An ideal situation for the Bitcoin network:

if the share difficulty were 31.25 PH, then each share would be a solution

to a block.if the share difficulty were 19.1 PH, then every second share would be a

solution to a block.if the share difficulty were 12.5 PH, then every thousandth share would

be a solution to a block.

That is, if the network difficulty is 31.25 PH and the share difficulty on the

pool is, say, 128 H, the pool must receive 244 million 414 thousand shares

to find a solution to one block. In other words, under ideal circumstances,

after every 244 million 414 thousand shares, the pool will find a block.

Why is the share difficulty needed?

If the difficulty is equal to one, the number of solved shares per second

will be more than** 1000** - that is, the current device hashrate in this case

will be much higher than the declared hashrate, but the daily hashrate will

still equal the actual device hashrate. Therefore, mining pools set the

share difficulties that can either be fixed or depend on the user's device.

The share difficulty is selected in a way that allows the miners work comfortably and see detailed statistics of their work while preventing the pool from “collapsing” due to the number of shares received.

**For ASIC devices**, the share difficulty is usually not fixed but rather

dynamic. For example, ASIC mining at difficulty level 1 is too low, and a

miner at 13.5 Th/sec sends thousands of shares per second. In fact, this

may lead to a situation where a miner with more powerful hardware can

solve the given share faster under the same difficulty.

**Network difficulty vs share difficulty**

The network difficulty is a mechanism built into the self-regulation of a

currency. The more miners (network hashrate), the higher the difficulty,

and network participants make less - and vice versa. Roughly speaking,

difficulty is a defensive reaction of the network. Difficulty for each coin is

calculated in a different way.

Example:

BTC - the difficulty is adjusted every 2016 blocks (every 14 days) so

that the average time between blocks is 10 minutes.ETH - recalculation of mining difficulty in the Ethereum network is

performed on each block.LTC - recalculation of the mining difficulty in the Litecoin network is

performed on each block.

Why does the pool set high shares difficulty?

The main factor is the optimization of the work of miners on the pool.

Shares with low difficulty are not always good. If the user is mining at too

low a difficulty, the mining hardware can spend a lot of time sending and

receiving data from the pool server, i.e., it will be idle, which will cause

rejections.

`The share difficulty does not affect the income as the payouts are `

proportional to the hashrate of the miner. With more complex shares, it

will be “convenient” for the device to find the correct solution to the block

without equipment downtime.

**Why do I often receive hardware shutdown alerts?**

The pool checks the work of the miner based on the shares. If you have a

weak device, the time gap between shares increases, and the pool

believes that the device is disconnected.

*For ASIC devices, it’s S11; ASICs without one board (or anything less than 25 - 50 MH/s) and, for GPU, everything below 4 GB (RX 460/470, GTX 1060 3GB).*