Bitcoin Forum

I know it can happen occasionally (yes, I did my probabilities class) but it's still scary when blocks are confirming every few minutes and then suddenly it grinds to a halt and nothing for the past 40 minutes.

Always wonder if something has gone terribly wrong.

Carry on.

https://blockchain.info/block/00000000000002b947ccad9a461c2dd3ef26bed8c0bcd556e59d0cf4d97f8c79
https://blockchain.info/block/00000000000002ba66922e098fd0c28a98d0383c4ec129561183ea221030e2db

and:

https://blockchain.info/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
https://blockchain.info/block/00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048

edit: while I was looking for the links two blocks were mined withing 1 minute intervals.

Yeah, as aantonop tweeted, "A watched blockchain doesn't hash.". Still 51+ minutes was scary. Anyway, all's well.

I understand that there is variance and block generation is a stochastic process.

Even assuming the hash rate is always rising, there is still a chance that it will require 100 years to generate the block, isn't it?

I wonder what's the probability of having unacceptable block generation time.

Yea, thats always a pain, especially if you're waiting for a Gox withdraw or something that sometimes does go terribly wrong. You just show up back at your computer and are like 'OH SHIT', especially if you forget to check blockchain.info.

:D If someone did the calculations, we might find it more probable than an address collision, and then the trolls would create a thread every other day about the "10 minute block myth."

Bitcoin can only adjust difficulty on a block's creation, right? Its not like it can go "oh screw its been 7 days since the last block was created, time to divide difficulty by C"?

Maybe just coincidence but ... I believe in numbers, not in coincidences.

https://bitcointalk.org/index.php?topic=315259.0

In random numbers (block generation time) coincidences happen fairly often. Otherwise, the martingale would be an infallible strategy.

"scary"  lol

There is also a chance that I go out onto the street then a bag with 100 million dollars, an aerolite, and Elvis Presley all drop out of the blue sky onto my head.

Correct. It's actually even more than that.

Bitcoin can only adjust the difficulty every 2016 blocks.

Darn. Is there any reason it can't tie difficutly increase to a time period instead?

That way we could decrease difficulty every X days and say to naysayers "see, even if something really dumb happens we're guaranteed a block in 2 years :D :D"

Because block timestamps can be inaccurate (either maliciously or by accident) and there's absolutely no way to verify when a block was really mined (and thus how long it has been since the last block). For example, say it's been twenty minutes since the last block, and then you receive a block with a timestamp a few seconds after the previous block. Was it really mined a few seconds after the last block, and you were just late in receiving it due to network lag? Is the miner deliberately using bogus timestamps in an attempt to jack up the difficulty for everybody else? Or is the miner's clock just twenty minutes slow? You don't know. Nobody knows. Fortunately, nobody needs to know, since Bitcoin doesn't care how long ago the last block was mined, and everything works as long as the majority of miners are keeping reasonably accurate time.

some this come

It happened on bytecoin (exact copy of bitcoin) network, one diff cycle was about 3-4 months. No problem at all, just wait more for 6+ conf.

Keep in mind that bitcoin diff can change by the margin of 4, in bytecoin example it when 4 times lower after that 2016 blocks were mined

oh please, it only happens every single day, real scary stuff!