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Bitcoin From Scratch – Part 1

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Re: Bitcoin From Scratch – Part 1

#31

Post by dang »

person_of_color wrote: post #17
ozankabak wrote: post #5

Clear, concise and to the point. Looking forward to reading the rest. If you finish the whole series and fix/improve the posts in this sequence using the feedback from here, I think it might serve as one of the go-to pages for technically inclined people who are interested to learn about Bitcoin and blockchains.

Except they’re polarising as hell. Expect someone to chime in and state how they are a complete waste of time and energy.

That's generally true. The trouble is that your post more or less does to the thread what you're predicting that people will do to the thread—the polarity of the high-order bit doesn't matter much. It's best to abstain.

https://news.ycombinator.com/newsguidelines.html

Re: Bitcoin From Scratch – Part 1

#32

Post by leorio »

ggrrhh_ta wrote: post #28

For people that need or want to know (really understand) in depth about Bitcoin without any previous background in Computer Science (for example, in Finance, investors, journalists, historians, curious people in general) I have to recommend Ted Nelson's "How Bitcoin actually works" (2014) from his series "Computers for Cynics" [0]. I enjoyed it. (+) [0] https://youtu.be/3CMucDjJQ4E (+) For the people with background…

that was entertaining

Re: Bitcoin From Scratch – Part 1

#33

Post by martinko »

nemo1618 wrote: post #2

> The PoW is suffice if the hash begins with a certain number of 0s This is a common explanation of PoW, but is actually incorrect. If you think about it, this would mean that the PoW difficulty could only increase (or decrease) by a factor of two. In reality, the block hash is simply interpreted as a (very large) number, and this number must be less than some other very large number (the "target"). So you do end up…

How is network consensus achieved on the difficulty adjustment?

Re: Bitcoin From Scratch – Part 1

#34

Post by exdsq »

trickstra wrote: post #29
jbverschoor wrote: post #25

Earlier quoted context omitted.

There’s a difference between mining bitcoins, and mining for network fees.

What difference would that be? Both the fees and the block reward go to the miner who first published a valid block with hash lower than the current difficulty. The only difference is where those bitcoins came from, but that has no impact on how easy it was to mine.

Yeah as a miner you add the fee and the earned coins to the single coinbase transaction, so it’s a single mining action to get both.

Re: Bitcoin From Scratch – Part 1

#36

Post by shuringai »

I really like the intention and good will behind the post but almost every part is incorrect (even on an abstract level not restricting to bitcoin). I feel like OP is yet another someone who needed the keyword "blockchain expert" on his/her linkedin profile and trying to justify it now with misleading and incomplete information.

Re: Bitcoin From Scratch – Part 1

#37

Post by johnpaulkiser »

martinko wrote: post #33
nemo1618 wrote: post #2

> The PoW is suffice if the hash begins with a certain number of 0s This is a common explanation of PoW, but is actually incorrect. If you think about it, this would mean that the PoW difficulty could only increase (or decrease) by a factor of two. In reality, the block hash is simply interpreted as a (very large) number, and this number must be less than some other very large number (the "target"). So you do end up…

How is network consensus achieved on the difficulty adjustment?

Each node independently comes to the new difficulty on their own in an entirely deterministic way.

After 2 weeks there should be 2016 blocks mined, 1 block every 10 minutes. After each 2 week period every node recalculates the new difficulty based on the actual number of blocks mined in the last 2 weeks. If the actual number of blocks produced was 25% higher than the target of 2016, then simply increase the difficulty by 25%.

Re: Bitcoin From Scratch – Part 1

#38

Post by tromp »

martinko wrote: post #33
nemo1618 wrote: post #2

> The PoW is suffice if the hash begins with a certain number of 0s This is a common explanation of PoW, but is actually incorrect. If you think about it, this would mean that the PoW difficulty could only increase (or decrease) by a factor of two. In reality, the block hash is simply interpreted as a (very large) number, and this number must be less than some other very large number (the "target"). So you do end up…

How is network consensus achieved on the difficulty adjustment?

It is computed using only information embedded in the block chain, specifically the timestamps of blocks 2016 * i and 2016 * (i+1).

Re: Bitcoin From Scratch – Part 1

#39

Post by martinko »

johnpaulkiser wrote: post #37
martinko wrote: post #33

Earlier quoted context omitted.

How is network consensus achieved on the difficulty adjustment?

Each node independently comes to the new difficulty on their own in an entirely deterministic way. After 2 weeks there should be 2016 blocks mined, 1 block every 10 minutes. After each 2 week period every node recalculates the new difficulty based on the actual number of blocks mined in the last 2 weeks. If the actual number of blocks produced was 25% higher than the target of 2016, then simply increase the difficult…

Thanks. Given that this relies on subjective timestamps, is this really entirely deterministic? I can imagine that one node counted 2014 blocks in the past two weeks, another 2015. What happens in such cases?

Re: Bitcoin From Scratch – Part 1

#40

Post by martinko »

tromp wrote: post #38
martinko wrote: post #33

Earlier quoted context omitted.

How is network consensus achieved on the difficulty adjustment?

It is computed using only information embedded in the block chain, specifically the timestamps of blocks 2016 * i and 2016 * (i+1).

But aren't blockchain timestamps unreliable? It was my understanding that difficulty was based on subjective node timestamps..
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