Updates & Forks - Discussion

Blockchain and Bitcoin 101
#163

Every node can choose how long they keep transactions in the mempool. Default is 2 weeks. So if you set a very low fee of 1 sat /byte when the network is very busy for 2 weeks, there is a change that your transaction gets lost. So that basic no transaction happened and the sender still has the bitcoins. Some wallets allow you to use RBF. (replace by fee) then you can boost the fee in case your transaction get stuck. You can also make a new transaction with the ‘unconfirmed’ change and give this a high fee (Child pays for parent) when you spend with outputs that are not confirmed yet, you create a ‘mempool package’

I don’t remember the quiz, but every miner can pick transactions he want. But will most of the time prioritize in sats/byte. So if 2 miners mine a block at the same time on the same blockheight, doesn’t mean the blocks are identical. In fact it’s not possible to be identical because the coinbase transaction is set to send to the miner’s address. So the hash will always be different and thus a different nonce will be required to make it a valid block.

Check this cool cartoon about the mempool:

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#164

So the money does not get lost if the transaction gets lost. That makes sense. It would be pretty bad if there were little loopholes through which money can get lost on the blockchain. You may want to double-check the quiz, not for me but for other students. Getting the answer wrong actually helped me a lot because it forced me to try to sort the matter out. My recollection is that the correct answer stated that the fork-defining blocks are equal.

Thank you so much for your help. I appreciate it (and unfortunately, I couldn’t open the link because I am not on github).

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#165

Yeah, in a transaction, You just try to change ownership of a bunch of bitcoin (sats) with adding a cryptographical lock that only the right receiver can unlock and spend again. If a transaction doesn’t happen for some reason, the sender still has the bitcoins. Only when a transaction is mined, It truely changed ownership

To view the file wich I linked before, I just uploaded on my website:

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#166

On the Fork Quiz, wouldn’t both answers A & C be correct for questions 3 & 4?

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#167

Hi Filip,
when we say 5-6 block confirmation it means whoever joined the short side and lets say mined couple of blocks will get dropped including the miner who started the fork?

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#168

Incredibly informative answer. I definitely see it as an ecosystem now that needs to be sustainable on all levels to keep balance. Thanks you so much

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#169

Quiz: Forks I can’t select 2 answers

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#170

Hello sir, which browser are you using? I have run the quiz, no issue for me on any answer, if you are using Brave Browser, try to deactivate the shields for the Academy.

If you have any doubt, please let us know so we can help you!

Carlos Z.

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#171

Thanks for the answer, I’m using Firefox maybe is from DuckDuckGo Privacy, I will try to deactivate for the Academy.

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#172

Continuing the discussion from Updates & Forks - Discussion:

Hi @Fabrice
I foud this paragraf:
“There are several technical issues that can arise with a sustained chain split. One is the issue of replay attacks, where transactions meant for one blockchain are confirmed on another, which can lead to accidental losses of money.”
in article :


You posted in the chat.
I can remember this risk was mentioned with Monero fork 4/2018.
How can I check node I am connected thru wallet is running legacy or fork Blockchain?
Is there any list of nodes running fork or legacy blockchain?
Or it is worse, and it depends on which miner legacy or fork pick up my transaction?
Tomas
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#173

Hey Filip

I am a bit confused about how a hard fork split in the chain can result in two different cryptocurrencies. Since a fork is based on the original chain, how is it possible for each individual chain to form their own cryptocurrency?

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#174

Hello Phillip, Thank you for the lessons :slight_smile:.

If the new Hard fork would accept txs from the new and old updates, then does this mean it is in competition for txs as well from other cryptocurrency fork?

Also looking to understand Sebastians question quoted below.

Many thanks!

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#175

Because a hardfork expand the rules, older nodes can’t validate new blocks that doesn’t meet te consensus rules, so the blockchain will split on the block where the hard fork happened and will share the same history until that particular block

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#176

Check the version of your client software

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#177

You don’t loose money if you send bitcoin to a another blockchain address that is still compatible with bitcoin (like a fork of bitcoin) . If you accidentally send btc to a bitcoin cash address, the bitcoin cash user can redeem the real bitcoin with his keys. Because ecdsa cryptography doesn’t care about wich blockchain you use, but you need to be able to unlock the bitcoins with your keys. But you can’t redeem bcash from a bitcoin user. The sender and reciever needs to be on the same consensus rules and blockchain to be able to transfer normally

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#178

thanks @Fabrice,
but what if I am sent bitcoin to bitcoin cash adress which was created after fork?

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#179

Public key cryptography is the same, If you didn’t used bech32 addresses. So the same keys can be used on multiple blockchains (if the network uses the same public/private key cryptography etcetera) the transaction only gets mined in the particular blockchain and the bitcoins get locked on any public key that fits the rules

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#180

Two more questions

  1. Which platform miners using for voting before fork?
  2. Who can add text (mesage) to the block? Miner, every one? How? Sorry, this mayby off topic.
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#181

@Fabrice
maybe I got it. The problem was not in bitcoin/bitcoin cash fork, because “only” block size has changed. But in monero, I mentioned in my original question, fork was about ASIC resistance. Fork changed hash functions, algorithm to eliminate ASIC miners.

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#182

Yeah, I know monero forks once and a while to keep asic resistant. I don’t know how exactly this works. Maybe Google knows.

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