Why is it that mining Bitcoin on a PC has long been unprofitable, but many people are still willing to do it?

“Master, what do you think about running a Bitcoin full node on my computer when I’m not playing World of Warcraft?” the soldier asked.
"Hey? Why do you have such an idea? This is not like your usual style."
"I think this is a pretty cool thing, and I can learn from it. Think about it, there are so many coins now, all of which are descendants of Bitcoin. Wouldn't it be cool to keep a copy of the full ledger of Bitcoin on my own machine?"
“Is it OK without block rewards?”
“Well, I can’t compete with ASICs anyway, and I don’t expect block rewards, so I just set up a node for fun.”
"Hmm... Your idea is interesting..."

Recently, in a certain community, it was discovered that some people would run a BTC full node on their home computers without any rewards. This situation has sparked heated discussions. This behavior is actually not uncommon, but it is worth pondering. Today, this article will summarize the different views on this matter. Readers are welcome to leave comments after the article for discussion.

Non-mining personal full node may make sense

1. Will anyone do something without being paid?

In the eyes of most people, especially big block advocates, Bitcoin is a "distributed ledger with built-in economic incentives". The core motivation for competing for the right to keep accounts is to obtain economic rewards (block rewards + transaction fees).

As Adam Smith famously said in The Wealth of Nations: "We do not get our dinner by the benevolence of butchers, brewers, or bakers, but by their regard to their own interests." There is also an old Chinese saying: "Nothing good can get you up early." Therefore, we naturally come to a conclusion - with the current ASIC mining machine computing power far exceeding that of ordinary computers by tens of thousands of times, it is impossible for ordinary home computers to run full nodes to win even the slightest mining opportunity. If you can't mine "mines", there will naturally be no rewards, and who would do something without economic benefits?

You know what, there are actually people who use ordinary home computers to run full nodes, and there are quite a few of them!

Data from June 2019 showed that the number of active Bitcoin addresses was around 1 million.

What about the number of full nodes? There are also about 10,000, which is about 1% of the active addresses.

As we all know, the current BTC computing power is controlled by a few mining pools. In other words, more than half of the 10,000 full nodes are simply full nodes that only synchronize the ledger. What are these people wasting their hard drive space and electricity for?

2. Motivation? Holding the ledger itself is a weapon

A practitioner who "runs full nodes on ordinary home computers" proposed a theory: "Bitcoin is essentially a global ledger. BTC holders are the owners of this ledger, and miners are just workers hired by the owner to keep accounts! How can power be transferred to workers? The ledger must be kept by the owner himself. If the owner keeps the full ledger himself, miners will not be able to make a big move. And precisely because of the high cost, small blocks are needed. Because the blocks are small, BTC can now run full nodes on ordinary computers and even mobile phones. Ordinary people run full nodes to keep their own ledgers. Wouldn't they be reluctant to spend a little money? You have a lot of gold at home, but you still need to build a vault. Don't you think this makes sense?"

Of course, you may have a question in mind: Do ordinary users who run full nodes have a say? When miners want to do evil or fork, how can these "full nodes" stop them? How can they express their consent or disapproval? After all, without computing power, there is no voting right.

The solution is also very simple, just allow the "evil miners" to fork freely to play with the new chain, and these "full nodes" continue to run the original chain. Bitcoin has always given people the right to fork, didn't BCH fork in the same way?

3. The core concept at the bottom: When gods fight, mortals will not suffer.

Whether a Bitcoin full node is running or not is different from whether it can be run. If it can be run, someone will run it, for example, there are nearly 10,000 full nodes in the entire network now; and it is definitely not that everyone will run it, let alone that no one will run it, just as the number of full nodes only accounts for 1% of the active addresses.

Under the concept of small blocks, the charm of decentralization lies in this. If you want to do evil and attack, you can fork a chain, but as long as there are enough honest individual full nodes, it is highly likely that the consensus and price of the original chain will exceed the forked chain. Of course, the price is determined by the market, and whichever the market thinks is good is the best. From the current perspective, BTC, which insists on small blocks, has not suffered any substantial threats in terms of price and consensus after experiencing so many forks in 2017.

Another important reason for opposing large blocks is based on this. Under small blocks, individuals can choose not to agree with the fight between mining tyrants. When gods fight, mortals will not suffer. Miners or development teams can freely fork a chain if they want to fight or do evil. But under large blocks, ordinary users do not have this right. When individual users are unable to run full nodes, their right to fork is blocked. One of the core features of Bitcoin is "allowing forks."

A full node that does not produce blocks may be just a mirage

1. What this world needs is not just safety or efficiency, but a balanced compromise.

In the eyes of many people, as long as they keep the entire ledger, miners will not be able to cause any trouble, which is a safe practice.

However, this is like everyone buying a safe and keeping their money in it. Except for a few wealthy people, how many ordinary people would do this?

The essence of protection is security, but the essence of security is the easiest to get wrong. Security is a probability problem, and calculating this probability requires a lot of knowledge. It is not based on intuition or even qualitative reasoning, but often requires mathematical calculations and experiments. In this case, which is greater, the probability of losing the ledger under large blocks or the probability of not being recognized when I have a ledger under small blocks? Instead of trusting feelings, it is better to trust logical reasoning and economic incentives.

2. If the theory that an individual is not a full node producing blocks is true, then what is the future of large blocks?

The current BTC ledger is about 200G, and it will take more than a decade to reach one terabyte. A 10T server hard drive costs more than 2,000 yuan. According to the current price of 10,000-20,000 yuan for a server + 10,000 yuan for a disk array, a 30-40T personal server will be enough for the ledger of the BCH large block in the next 10-20 years, and this is based on the assumption that all BCH 32M blocks are filled.

So, here comes the question. For individual users on BTC, under the premise that they cannot generate blocks, will anyone be willing to use their own 5,000-6,000 yuan PC to run a full node? Then, for BCH/BSV, will anyone be willing to spend 20,000-30,000 yuan to build a server to run it?

Could it be that the core point of the dispute between small blocks and large blocks is only the difference in cost between 5,000-6,000 and 20,000-30,000? This seems... a bit unreasonable?

3. Cybersecurity and future consensus

There are three factors that have to be considered.

First, under the current protection of BTC with 10,000 personal full nodes, whether someone spends money to buy 10,000 personal computers or hackers control 10,000 zombie hosts (currently there are more than one million zombie hosts in the entire network), the number of such "non-mining personal full nodes" can easily exceed the honest full nodes. At that time, the role of honest full nodes will be greatly weakened.

Second, in the case of "miner collusion", the fork event discussed above occurs. If most of the computing power goes to the new chain, the old chain has almost no computing power (or only the CPU computing power of individual full nodes), and the mining farm allocates some ASIC computing power to attack the old chain to ensure that the old chain cannot be traded, then where should this old chain, or the so-called original chain, go? It seems that the only way is to change the algorithm... and once the algorithm is changed, it may not be so easy to maintain the highest price and consensus.

Third, the next decade is about what BTC and blockchain can do, whether BTC can be a "electronic gold" and whether it is still useful. At present, almost all chains are useless and can only transfer money to each other. The original chain BTC consensus is the easiest to maintain and reaches the highest market price. There is nothing wrong with it. The debate between small blocks and large blocks needs to wait until BTC is not useful enough, the block reward has been halved twice, and the TX (transfer) on the BCH or BSV chain takes off in large quantities. It may be meaningful to discuss it again.

summary

Finally, I want to say that there are actually a lot of things to study about Bitcoin. Sometimes you think you understand it, but in fact you only have a superficial understanding. When you think you only have a superficial understanding, it is very likely that you have just started.

If you don’t believe it, ask yourself, you may know “mining, block rewards, public key and private key, double spending…”, and you are familiar with the expansion dispute and fork history of BCH and BSV, but can you explain it clearly to others:

• Is there a saying that “there is no such thing as Bitcoin, only UTXO”?

• What are Bitcoin's block structure, Merkle tree, SPV node, and segregated witness?

• How do mining pools package transactions? What is a memory pool? What is an orphan block? What exactly happened to the BCH downtime and rollback issue that lasted for more than an hour during the upgrade? What happened to the block reorganization during the BSV 128M block stress test?

• Even more, is Bitcoin really Turing incomplete under the script and dual-stack architecture?