Explain like I'm 5 years old and my other half of the brain is surgically removed :) I don't want to put a lot of stress on my brain

1.What are these bitcoin nodes and what purpose they serve?

2.and also why they are still running?

3.and does miners use them to mine or validate transaction anymore?

4.how bitcoind is related to any of them?

0-Bitcoin Core

1-Bitcoin Unlimited nodes

2-Bitcore nodes

3-Bitcoin UASF nodes

4-btc1 nodes

5-Bitcoin Knots nodes

6-bcoin nodes

7-Bitcoin Classic nodes

8-btcd nodes

9-Bitcoin XT nodes

10-TRB nodes

11-libbitcoin nodes

12-Bitcoin ABC

2 Answers 2


The rules of bitcoin, much like the rules of a board game, are fixed. In board games, there is an instruction booklet that tells you what the rules are, and anyone not adhering to the rules is breaking them, which is known as cheating.

Bitcoin's rules were laid down by Satoshi Nakamoto, its inventor, and its rules are enforced by each player (node). Nodes check if the blocks are constructed according to the rules of Bitcoin, and punish miners who construct cheating blocks.

Having played Catan quite a bit, I've found that some people enjoy playing with house rules. Some people feel that every player should start with at least one of each resource, for example. These rules can be enforced by the whole group, as if they were in the instruction manual.

The same is true for bitcoin. Some people feel that the Bitcoin protocol is better suited by having small additions to the rules, or notable omissions. These people are free to write their own software, which enforces their own rules on Bitcoin.

Some are just translations of the bitcoin instruction manual to another language. Some aim to change fundamental parts of the protocol, such as the btc1 nodes, or Bitcoin XT nodes.

edit: The most-used client is bitcoind, which is the command-line interface of "Bitcoin Core". Due to the fact that a majority of people are using this client, it dictates the current consensus rules (the rules of the game), and other clients either adhere to it, or risk getting "forked".

Node software has been politicized these past few years. This is a different topic altogether, and I recommend you google "the bitcoin scaling debate" for a primer.

  • so what nodes majority of miners use to mine and validate TX.. and how many nodes failed or dead .. due to not meeting consensus?
    – user380208
    Dec 12, 2017 at 8:08
  • Quite a few nodes failed, though people can still choose to work with them as long as they adhere to the consensus rules used by the majority. Exact figures are difficult to find, but you could keep an eye on coin.dance/blocks for an overview of the last 1000 blocks. Miners tend to list their client in the block message. Dec 12, 2017 at 8:26
  • if that is true than BitcoinABC is used for mining bitcoin cash and BitcoinCode for mining Segwit and old Bitcoin Tx .. right? also recently i keep hearing these nodes 1. Bitcoin knots 2. Bitcoin Unlimited? .... or this means that node B5(blocksize 5) is willing to accept B5 type of this tx however it will also accept and verify tx made for bitcoincore and segwit?
    – user380208
    Dec 12, 2017 at 8:57

The bitcoin network is made up of many nodes, as well as miners. If you are a user you can run a node to verify that you are connected to the bitcoin network and your transactions are confirmed.

There are a few different implementations of the software, such as the ones you listed. All of the different implementations must adhere to the strict consensus rules defined in the bitcoin protocol, or else the rest of the network will ban them. The code that is not consensus critical can be altered, so each of the implementations may be a little different.

Most big miners probably run their own modified versions of the code, to suit their needs best.

  • "All of the different implementations must adhere to the strict consensus rules defined in the bitcoin protocol," - you mean they must at least support core requirements like (A segwit-compatible wallet MUST support pay-to-script-hash (BIP16) and its address format (BIP13)...) as specified whenever they release BIP
    – user380208
    Dec 12, 2017 at 9:39
  • No, the consensus code pertains to things such as the amount of bitcoins included in the block reward, the mining difficulty, the type of proof-of-work required, the block size limit, etc. A node doesn't have to explicity support making a certain tx type, it just has to play by the same basic rules as the rest of the network.
    – chytrik
    Dec 12, 2017 at 11:15
  • A node doesn't have to explicity support making a certain tx type.. ..... however thats not the case with segwit? it aggregates witness in its merkel tree
    – user380208
    Dec 12, 2017 at 12:13
  • The activation of segwit was a backwards compatible softfork: old nodes that don't explicitly support segwit still accept all segwit nodes/traffic as being in consensus with the network.
    – chytrik
    Dec 12, 2017 at 23:27

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