In the world of mining, not all work performed leads to a reward. Sometimes miners or pools solve a problem, but for various reasons, their work turns out to be useless. In pool statistics, you might encounter the term “stale shares,” and in the news, “orphan blocks.” Let’s break down what these terms mean and what their fundamental difference is.
Stale Shares: A Problem on Your End
This is the most common term encountered by an average miner. A Stale Share is a valid solution (share) that your ASIC sent to the pool, but it arrived too late. The pool rejects it because a new block in the network has already been found by someone else.
Imagine you’re solving a crossword puzzle in a newspaper against the clock. You’ve filled in the last word, but at that moment, all the correct answers have already been announced on the radio. Your solution is correct, but it’s already useless.
Reasons for Stale Shares:
- High ping to the pool server. The longer the signal takes to travel from your ASIC to the pool and back, the higher the probability that someone else will find a block during that time.
- Poor internet connection quality. Packet loss and unstable connections lead to delays.
How to combat this?
- Choose a pool server geographically closest to you. Almost all large pools have servers in Europe, Asia, and North America.
- Use a wired connection (Ethernet) instead of Wi-Fi. It is always more stable.
A small percentage of stale shares (up to 1-2%) is considered normal. But if this value is higher, it’s worth checking your internet connection and pool settings.
Orphan Blocks: Bad Luck in the Race
An Orphan Block is a completely valid, correctly formed block that was not included in the main blockchain chain. This happens due to network delays.
Mining is a global race. Sometimes, two miners in different parts of the world find a solution for a block almost simultaneously, with a difference of fractions of a second. Both blocks begin to propagate through the network. But ultimately, the network will only accept one of them – the one that reaches the majority of nodes faster. The second block will become an “orphan.”
This is not someone’s mistake, but simply an element of randomness and a result of the physical limitations of information propagation speed. A miner or pool that finds an orphan block receives no reward for it.
You often encounter the synonym “Stale Block,” but it’s important not to confuse it with “Stale Share.” A Stale Block is a network-wide problem, while a Stale Share is a problem with your connection to the pool.
Uncle Blocks: An Ethereum Concept
An Uncle Block is a unique concept that existed in the Ethereum network when it operated on the Proof-of-Work algorithm. In essence, it’s the same as an orphan block, but with one important difference: Ethereum partially rewarded miners for finding them.
Why was this needed? In Ethereum, the block time was much shorter (about 15 seconds) than in Bitcoin (10 minutes). This led to a much larger number of orphan blocks. To motivate miners to include information about these “orphans” in the main chain (thereby increasing its security), the protocol paid a small portion of the reward both for finding an “uncle” and for including it in the next block.
In the Bitcoin network, the concept of “uncle blocks” does not exist. Any block that does not make it into the main chain is an orphan and is not rewarded.
