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Author Topic: Dead Cat Bounce ??!!  (Read 8336 times)
DeathAndTaxes
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Gerald Davis


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November 11, 2011, 05:16:01 PM
 #81

Difficulty doesn't just adjust in huge steps as I understand it; if the past several blocks are solved quickly, the real-time difficulty will adjust as well.

No.  It only adjusts every 2016 blocks.  In hindsight some sort of continually adjusting formula (likely exponential decay of past 2016 blocks) which altered difficulty after each block would have been better ... for a lot of reasons.  For example namecoin would have never gotten "trapped" if difficulty adjusted after each block.
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November 11, 2011, 06:06:15 PM
 #82

In hindsight some sort of continually adjusting formula (likely exponential decay of past 2016 blocks) which altered difficulty after each block would have been better ... for a lot of reasons.
I don't think that would converge globally. With frequent adjustments each pool would distrust blocks from the others and the network would split into islands. Infrequent adjustments decrease the probability of network splits. 2016 may not be optimal, but seem very safe to assume that in two weeks a clear maximum difficulty leader will stabilize globally.

Please comment, critique, criticize or ridicule BIP 2112: https://bitcointalk.org/index.php?topic=54382.0
Long-term mining prognosis: https://bitcointalk.org/index.php?topic=91101.0
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November 11, 2011, 07:36:19 PM
 #83

In hindsight some sort of continually adjusting formula (likely exponential decay of past 2016 blocks) which altered difficulty after each block would have been better ... for a lot of reasons.
I don't think that would converge globally. With frequent adjustments each pool would distrust blocks from the others and the network would split into islands. Infrequent adjustments decrease the probability of network splits. 2016 may not be optimal, but seem very safe to assume that in two weeks a clear maximum difficulty leader will stabilize globally.

Pools don't need to trust other pools.  IF the block is valid difficulty is adjusted.  Using an exponential decay function would avoid fluctuations and instead a smoother difficulty adjustment.  Currently pools need to trust the 2016th block when they recompute the difficulty once every 2016 blocks.

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Infrequent adjustments decrease the probability of network splits.
Difficulty adjustments don't split networks.  Orphaned blocks split networks.  I mean what is going to happen a pool is going to trust the block as valid ans work on that block chain but then not trust the difficulty adjustment despite their client computing the exact same difficulty adjustment?
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November 11, 2011, 08:39:42 PM
 #84


2016 blocks = 100800 BTC. At the start of a new difficulty, a dedicated agency like the NSA could probably mine 100,000 BTC in a day. Keeping the same hashrate they could mine another 100,000 in four days at the new difficulty they set. If you doubt this, remember the NSA has their own chip fab...they might have even tested their tech, search for "mystery miner"...


Looks like mystery miner only mined a max of 500 GH:

.. which is now less than 5% of the global hashrate of 10 TH.  I'm guessing this is someone at Pixar or some other render farm.

To mine an entire difficulty adjustment in a day would take 14 times the current network speed of, or 140 TH, which is 280 times the mystery miner's peak hashrate.  We're safe from this mystery miner, but it doesn't say anything about the NSA, who does have the resources to

I'm guessing most of the NSA thinks bitcoin is cool - they're just a bunch of crypto-geeks, after all.  It's about what the top brass thinks: is bitcoin an emerging threat that should be taken out, or is it a technological breakthrough that should be nurtured, not fucked with?  My guess is the latter, but not for reasons of the public good.  Rather, with their intel capabilities, the public blockchain could be a boon for their investigative teams.
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November 11, 2011, 09:08:15 PM
 #85

In hindsight some sort of continually adjusting formula (likely exponential decay of past 2016 blocks) which altered difficulty after each block would have been better ... for a lot of reasons.
I don't think that would converge globally. With frequent adjustments each pool would distrust blocks from the others and the network would split into islands. Infrequent adjustments decrease the probability of network splits. 2016 may not be optimal, but seem very safe to assume that in two weeks a clear maximum difficulty leader will stabilize globally.

Pools don't need to trust other pools.  IF the block is valid difficulty is adjusted.  Using an exponential decay function would avoid fluctuations and instead a smoother difficulty adjustment.  Currently pools need to trust the 2016th block when they recompute the difficulty once every 2016 blocks.

Quote
Infrequent adjustments decrease the probability of network splits.
Difficulty adjustments don't split networks.  Orphaned blocks split networks.  I mean what is going to happen a pool is going to trust the block as valid ans work on that block chain but then not trust the difficulty adjustment despite their client computing the exact same difficulty adjustment?
Dude, far out. You could've just written: sorry, I had a thinko. Now you've proven that you don't understand the basics of the global convergence of the Bitcoin protocol. I guess I now better understand the plight of Gavin and other core developers that simply clam up and don't discuss any changes in the core protocol. One one hand miners are essential to the overall security, but on the other hand miners most likely don't understand what makes that network stable.

I normally cut the quotes, but this one is worth preserving in full.

Please comment, critique, criticize or ridicule BIP 2112: https://bitcointalk.org/index.php?topic=54382.0
Long-term mining prognosis: https://bitcointalk.org/index.php?topic=91101.0
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November 12, 2011, 12:54:37 AM
 #86


2016 blocks = 100800 BTC. At the start of a new difficulty, a dedicated agency like the NSA could probably mine 100,000 BTC in a day. Keeping the same hashrate they could mine another 100,000 in four days at the new difficulty they set. If you doubt this, remember the NSA has their own chip fab...they might have even tested their tech, search for "mystery miner"...


Looks like mystery miner only mined a max of 500 GH:

.. which is now less than 5% of the global hashrate of 10 TH.  I'm guessing this is someone at Pixar or some other render farm.

To mine an entire difficulty adjustment in a day would take 14 times the current network speed of, or 140 TH, which is 280 times the mystery miner's peak hashrate.  We're safe from this mystery miner...

Is there any reason to be confident that was MM's full power and not just a small test to see if the system worked? Or that even if it was his full power at the time he hasn't invested in more hardware?

(I dont always get new reply notifications, pls send a pm when you think it has happened)

Wanna gimme some BTC for any or no reason? 1FmvtS66LFh6ycrXDwKRQTexGJw4UWiqDX Smiley

The more you believe in Bitcoin, and the more you show you do to other people, the faster the real value will soar!

Do you like mmmBananas?!
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November 12, 2011, 01:22:15 AM
 #87

Is there any reason to be confident that was MM's full power and not just a small test to see if the system worked? Or that even if it was his full power at the time he hasn't invested in more hardware?
No, there's no way to be confident given that MM scaled up and then stopped once they reached 50% of the total network power.

But scaling up to 280 times their earlier rate is not an easy thing to do, and is not as simple as buying 280 times more hardware: MM would require additional floorspace likely in a hosted location, HVAC, more power outlets, more breakers, bigger power drop, etc. If each machine/device gets 1 GH, they'd need 140,000 machines/devices.  There might not even be enough floorspace in a local hosted location, and they'd have to construct their own facility to house the operation, a multi-year project in and of itself.

Also, there's installation time: it took MM two weeks to scale up to 500 GH, and at that installation rate, it would take 10 years to install 140 TH.  Clearly it would need to be a whole team to work on such a project, perhaps two: one larger one for install, and another for upkeep.

MM's scale and timing was just about right for an unused or underused render farm between projects.  500 GH is a couple of thousand machines, and three weeks of scaling then suddenly ending sounds about right from a business perspective, too.

And if you are still worried, support your local FPGA miner!  It's the only way to attempt to scale up and compete with this or any other future Mystery Miner.
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November 12, 2011, 02:38:47 AM
 #88

Is there any reason to be confident that was MM's full power and not just a small test to see if the system worked? Or that even if it was his full power at the time he hasn't invested in more hardware?
No, there's no way to be confident given that MM scaled up and then stopped once they reached 50% of the total network power.

But scaling up to 280 times their earlier rate is not an easy thing to do, and is not as simple as buying 280 times more hardware: MM would require additional floorspace likely in a hosted location, HVAC, more power outlets, more breakers, bigger power drop, etc. If each machine/device gets 1 GH, they'd need 140,000 machines/devices.  There might not even be enough floorspace in a local hosted location, and they'd have to construct their own facility to house the operation, a multi-year project in and of itself.

Also, there's installation time: it took MM two weeks to scale up to 500 GH, and at that installation rate, it would take 10 years to install 140 TH.  Clearly it would need to be a whole team to work on such a project, perhaps two: one larger one for install, and another for upkeep.

MM's scale and timing was just about right for an unused or underused render farm between projects.  500 GH is a couple of thousand machines, and three weeks of scaling then suddenly ending sounds about right from a business perspective, too.

And if you are still worried, support your local FPGA miner!  It's the only way to attempt to scale up and compete with this or any other future Mystery Miner.
Visualize a 1U server packed full of custom ASIC crypto-hashers chips, then picture a rack of 30 of those 1U servers, then picture a row of 20 racks of those:


Then picture an aircraft hangar-sized building filled with that:


Then picture more than ten of those aircraft hangars around the world. And these pictures are just Facebook, not a government.

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November 12, 2011, 01:03:58 PM
 #89

Then picture more than ten of those aircraft hangars around the world. And these pictures are just Facebook, not a government.

Picture world peace.

Well, it's more likely than that, got to give you that much.

PGP key molecular F9B70769 fingerprint 9CDD C0D3 20F8 279F 6BE0  3F39 FC49 2362 F9B7 0769
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