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Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

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Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#51

Post by rajacombinator »

Spivak wrote: post #32
hexane360 wrote: post #6

Earlier quoted context omitted.

Can you explain the multiple meanings you see in the question?

* What is the average time it takes to mine a block? * If I choose a time uniformly what is the expected time it will take to mine that particular block. The difference between them being that blocks that take a long time occupy more space on the timeline than shorter blocks and are therefore more likely to be chosen.

What an appropriate username for that comment...! (Yes, the question is poorly worded.)

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#53

Post by Retric »

fyfy18 wrote: post #50

Say you have 10,000 miners, once you find a hash you can start all your miners mining the next block. Can you use the time between blocks to your advantage? If you find the hash after say 6 minutes, you could delay broadcasting the block to the network for another minute or two, and give yourself an advantage. Yes there’s a risk another miner would find the same hash, but statistically you could estimate the optimal…

There is zero benefit in waiting. Supose you had 1/3 of the hashing power and got it in the first second. You have a 1/3 chance of getting the extra block before someone else gets the first block and published risking your block.

However, if you publish the first block you still have a 1/3 chance of getting the next block first and ending up with 2 blocks. Thus waiting provides risk but zero gain.

In theory this changes if you can do a 51% attack, but that erodes trust in the block chain.

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#54

Post by rjp0008 »

fyfy18 wrote: post #50

Say you have 10,000 miners, once you find a hash you can start all your miners mining the next block. Can you use the time between blocks to your advantage? If you find the hash after say 6 minutes, you could delay broadcasting the block to the network for another minute or two, and give yourself an advantage. Yes there’s a risk another miner would find the same hash, but statistically you could estimate the optimal…

There is more than one solution to a block, so if someone does find it before you it's probably not the same solution. Making your head start worthless.

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#55

Post by JeremyBanks »

fyfy18 wrote: post #50

Say you have 10,000 miners, once you find a hash you can start all your miners mining the next block. Can you use the time between blocks to your advantage? If you find the hash after say 6 minutes, you could delay broadcasting the block to the network for another minute or two, and give yourself an advantage. Yes there’s a risk another miner would find the same hash, but statistically you could estimate the optimal…

More or less, yes. This is a known minor weakness in the protocol. See https://arxiv.org/abs/1311.0243

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#56

Post by tlrobinson »

ballenf wrote: post #14

Does this mean that the second block from a random point in time is, on average, 20 minutes away? Anyone know what the longest wait time on a block in recent history was? Final question -- do large mining operations network their miners so that they don't overlap their hashes. I'm thinking the overhead in doing that would probably be counter-productive given the massive problem space. But, if they were networked that…

> do large mining operations network their miners so that they don't overlap their hashes

Interestingly, it's hypothesized that Satoshi did this:

> He suggested that Satoshi had access to 58 machines for mining, so to avoid checking the same nonce twice he gave each machine a different id, which was stamped in the LSB of the nonce.

https://bitslog.wordpress.com/2013/09/03/new-mystery-about-s...

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#57

Post by benchaney »

rjp0008 wrote: post #54
fyfy18 wrote: post #50

Say you have 10,000 miners, once you find a hash you can start all your miners mining the next block. Can you use the time between blocks to your advantage? If you find the hash after say 6 minutes, you could delay broadcasting the block to the network for another minute or two, and give yourself an advantage. Yes there’s a risk another miner would find the same hash, but statistically you could estimate the optimal…

There is more than one solution to a block, so if someone does find it before you it's probably not the same solution. Making your head start worthless.

Adding to this. If two miners both discover a solution it is astronomically unlikely that it will be the same solution.

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#58

Post by modeless »

justonepost wrote: post #33
rusbus wrote: post #29

TLDR: Since blocks that take a long time to mine fill up more wall-clock time, if you pick an arbitrary instant of wall clock time, you're more likely to be in a "slow" block than a fast block. Specifically, you expect to wait 2x the average.

Thanks. Why can't all math teachers talk like that? I mean... I know you're clever and all, but if you were really clever you'd explain it in a way that's easy to understand. Still, kudos to the OP. That was a great attempt to be precise.

That simple explanation is exactly wrong though! You don't expect to wait 2x the average. You expect to wait 1x the average, but you also expect that when you start waiting the previous block happened 1x the average time ago, and 1+1=2.

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#60

Post by southpawflo »

wickawic wrote: post #38
axitanull wrote: post #34

Earlier quoted context omitted.

Understanding is one thing, explaining in layman or easy to undertand terms is another, and sometimes it takes a lot of effort.

Explaining is usually more difficult than understanding, as well.

I've had multiple teachers tell me that if you can't explain something you don't completely understand it yet. grok what I'm saying? :)
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