What does a node do?

[Jet Cash]

So a full node verifies a transaction, and a miner is rewarded for the additional task of building a new block. The transaction fee is related to a transaction, so why doesn't the first node to verify it get the fee? Is it because they can't register their verification without building a new block? Would it not be fairer to reward the first node for verifying the transaction, and reward the miner for building the block? Of course the miner would get any transaction fees if he was the first to verify them in his block, and there must be a high probability that miners will be the first on many transaction. This approach would reduce the rewards for SPV miners.

[shorena]

So a full node verifies all transactions and blocks, and a miner is rewarded for the additional task of building a new block.

Yes, with slight corrections in italic.

The transaction fee is related to a transaction, so why doesn't the first node to verify it get the fee?

Because the fee is by design for the miner. The verification does nothing "for" the transaction other than allowing it to be forwarded to other nodes.

Is it because they can't register their verification without building a new block?

A verification is not the same as a confirmation. A verification is just "yep, thats fine accoring to the network rules, I will tell my peers about it". A confirmation is "this transaction is now very unlikely to be ever reversed". Verifications are easy, confirmations are hard and expensive, because they require finding a block. They require "proof of work".

Would it not be fairer to reward the first node for verifying the transaction, and reward the miner for building the block?

Maybe it would be a good idea to reward full nodes, but keep in mind that finding a block is the important part. Its currently rewarded by 25 BTC on top of the fees, but this reward halfes every 4 years. So over time, the fees have to be the reward to find blocks at all. If there is no reward, less people would try and it would become easier. This would make bitcoin easier to attack.

Of course the miner would get any transaction fees if he was the first to verify them in his block, and there must be a high probability that miners will be the first on many transaction. This approach would reduce the rewards for SPV miners.

SPV Miners still get the 25 BTC block finding reward, even if they dont verify anything. Well the reward is taken back if it turns out that they build on top of an invalid block, but thats the risk they are willing to take.

[Jet Cash]

So do the SPV miners still get the transaction money even though they haven't verified? What happens when it becomes too difficult to find new blocks, will it be impossible to transfer Bitcoins?

[ranochigo]

So do the SPV miners still get the transaction money even though they haven't verified? What happens when it becomes too difficult to find new blocks, will it be impossible to transfer Bitcoins?

As long as the previous block follows the network rules and it doesn't get orphaned. SPV mining deducts the time used for verifying. They assume that the longest chain is valid.*

Difficulty automatically adjusts to make the blocks to go to 10 minute intervals. If it's faster, it will increase and vice versa. However, if a large miner decides to shut down their farm, it can get affected. Only if 50% of the network shuts down, blocks would be twice as long for 2016 blocks. The transaction speed of Bitcoin is instant, confirmation is not.


*Mining pool runs a full node but due to how SPV works, they will continue to mine on invalid chain.

[Dofnatues]

So do the SPV miners still get the transaction money even though they haven't verified? What happens when it becomes too difficult to find new blocks, will it be impossible to transfer Bitcoins?

As long as the previous block follows the network rules and it doesn't get orphaned. SPV mining deducts the time used for verifying. They assume that the longest chain is valid.*

*Mining pool runs a full node but due to how SPV works, they will continue to mine on invalid chain.

Does it verification use a lot of CPU power? I used to mine llitcoin with a very low end CPU and did not see any problem?

[shorena]

So do the SPV miners still get the transaction money even though they haven't verified? What happens when it becomes too difficult to find new blocks, will it be impossible to transfer Bitcoins?

As long as the previous block follows the network rules and it doesn't get orphaned. SPV mining deducts the time used for verifying. They assume that the longest chain is valid.*

*Mining pool runs a full node but due to how SPV works, they will continue to mine on invalid chain.

Does it verification use a lot of CPU power? I used to mine llitcoin with a very low end CPU and did not see any problem?

No verification is usually not much work for the CPU. Again verification is not mining.

[ranochigo]

So do the SPV miners still get the transaction money even though they haven't verified? What happens when it becomes too difficult to find new blocks, will it be impossible to transfer Bitcoins?

As long as the previous block follows the network rules and it doesn't get orphaned. SPV mining deducts the time used for verifying. They assume that the longest chain is valid.*

*Mining pool runs a full node but due to how SPV works, they will continue to mine on invalid chain.

Does it verification use a lot of CPU power? I used to mine llitcoin with a very low end CPU and did not see any problem?

No. The proporgation of block and verification does take sometime. Those miners who SPV mines listens on the other pools for block changes. They then check the coinbase for conflicting transactions and use the hashes to generate a new block header to mine. This essentially means that the SPV miner does not verify the block and trust that the other miner follows the network rules(eg. Not putting a 10k BTC block reward). If the miner makes a mistake and mines a block which doesn't follow the network rules, the SPV miners will continue to build on that chain and thus lose all the block rewards since they are mined on the wrong fork.

SPV mining can reduce the chances of getting the block orphaned.

[shorena]

-snip-
SPV mining can reduce the chances of getting the block orphaned.

While its true, the main problem is bad pool software AFAIK. SPV mining is meant for the time while the pool software verifies the last block and builds a new block with possible transactions to include. This takes time and during that time miners have no work to do. Since miners that have nothing to do are a waste of money, they mine on an unverified and empty block. The main issue for orphans is the time it takes for a block you found to reach other miners. If two pools find a block at the same time, the block that reaches 50% of the networks hashrate first will win the race.

[Jet Cash]

This seems to be a vulnerability. If the Fed wanted to undermine the stability of the blockchain, then it seems there are techniques that they could use. Even if it just increases the difficulty in registering new blocks, it could discourage miners, and thus weaken the community.

[shorena]

This seems to be a vulnerability. If the Fed wanted to undermine the stability of the blockchain, then it seems there are techniques that they could use. Even if it just increases the difficulty in registering new blocks, it could discourage miners, and thus weaken the community.

If you would buy mining hardware to find blocks they would increase bitcoins strength. Bitcoins security comes from the fact that its hard to find a block. If its easy to find a block its also easy to find a replacement for a block. If you can find a replacement for a block you have a chance to rewrite bitcoin history. That is commonly called a 51% attack, even though >50% would be more accurate.

[Blue_Panda73]

What is the main difference between a full node miner and a SPV miner? If the verification uses little CPU power, so little time, why does not the SPV miner verify the block?

[ranochigo]

What is the main difference between a full node miner and a SPV miner? If the verification uses little CPU power, so little time, why does not the SPV miner verify the block?

A normal miner would verify the block completely to ensure that it follows the rules that the miner knows it should. SPV miners looks at the coinbase for conflicting transactions and use the hash for the next block.

In mining, every second of latency is important. The faster you mine a block and proporgate it, the lesser chance it have to be orphaned. SPV pool mining software should allow users to mine on unverified block while it verifies. If it doesn't follow the rule, the pool should ask the miners to abandon it.*

*CMIIW.

[legendster]

I gather that once I have downloaded the blockchain, I will be running as a node every time I start Bitcoin core. So what will my computer be doing? As I will be using public WiFi until I finish my project (and maybe for some time afterwards), I won't be contributing a lot to the community, so what can my computer do?

Will it be supplying blocks to other users downloading the blockchain?
Will I be part of the transaction verification process?
What other services will I be able to contribute?

Whenever you run a node or download the BTC core data you are basically downloading the complete registry of bitcoin and yes you will become a part of the Bitcoin network, think of it much like the Skynet from the terminator movies.

[number2]

I understand what this all means, but are there risks of running a node in which someone could use a false code in order to get into your system so that they could steal your information or even your Bitcoin?  I was thinking of this when I seen an opportunity to test out as a node, but I was concerned about these things.

[achow101]

I understand what this all means, but are there risks of running a node in which someone could use a false code in order to get into your system so that they could steal your information or even your Bitcoin?  I was thinking of this when I seen an opportunity to test out as a node, but I was concerned about these things.

No. Unless there is a 0-day in the way that Bitcoin Core handles messages, this is not possible.

[RealBitcoin]

A node is an online bitcoin core client. It downloads and uploads the blockchain to the other nodes. (like a torrent client would do)

It's esentially 1 unit of the network. Every miner is a node, but not every node is a miner.

[Blue_Panda73]

A node is an online bitcoin core client. It downloads and uploads the blockchain to the other nodes. (like a torrent client would do)

It's esentially 1 unit of the network. Every miner is a node, but not every node is a miner.

If it is such a simple configuration, why are there so fewer nodes in the network? I remember there are only 6000 full nodes.

[Jet Cash]

If it is such a simple configuration, why are there so fewer nodes in the network? I remember there are only 6000 full nodes.

6001 now

I guess people don't want to pay the overhead in running a full node, when they don't get any reward. I only start the core for a while when I want to check for coins reeceived, and to keep the blockchain up to date.

[ranochigo]

If it is such a simple configuration, why are there so fewer nodes in the network? I remember there are only 6000 full nodes.

6001 now

I guess people don't want to pay the overhead in running a full node, when they don't get any reward. I only start the core for a while when I want to check for coins reeceived, and to keep the blockchain up to date.

There's currently 5667 reachable nodes*, it has decreased drastically. Unless you're a developers or want extra security, a SPV node would often suffice. The main problem of Bitcoin Core is disk space and bandwidth, that's pretty much all why Bitcoin users do not want to run it. Why run Core when you can run SPV clients right?

*Only nodes that enabled port 8333 and allowed connection from bitnodes.

[Jet Cash]

I understood that you could improve security by running a full node, but I haven't had a chance to investigate that yet. I need to understand more about the operation of Bitcoin and the blockchain first. Disk space isn't a problem these days, but bandwidth is if you are running Windows 10 (it's probably a massive security risk as well).