Bitcoin Forum

Bitcoin => Development & Technical Discussion => Topic started by: Pajeu on March 11, 2014, 05:39:52 PM



Title: Difficulty vis-a-vis less hashing power.
Post by: Pajeu on March 11, 2014, 05:39:52 PM
Hi.

Quick question from someone new to this universe. If the exchange rate BTC USD falls to say, 1BTC = 10 USD, presumably some people already in the BitCoin ecosystem would give up adding hash power, maybe even pull out of the whole enterprise. In this case of less hashing power at the margin, what would happen to the rate of increase of the difficulty? I think the difficulty number itself would not fall, but I´m not sure.

Thanks.


Title: Re: Difficulty vis-a-vis less hashing power.
Post by: blueangel01 on March 11, 2014, 05:52:04 PM
The difficulty will change on the set amount of block. The block will be solved longer than 10 mins because there is less hash power. It might take days to solve one block. The difficulty will decrease eventually after every 504 blocks.

I hope that helps.


Title: Re: Difficulty vis-a-vis less hashing power.
Post by: Remember remember the 5th of November on March 11, 2014, 05:53:42 PM
The difficulty will change on the set amount of block. The block will be solved longer than 10 mins because there is less hash power. It might take days to solve one block. The difficulty will decrease eventually after every 504 blocks.

I hope that helps.
The difficulty changes every 2016 blocks in Bitcoin.


Title: Re: Difficulty vis-a-vis less hashing power.
Post by: Korbman on March 11, 2014, 05:56:46 PM
Quick question from someone new to this universe. If the exchange rate BTC USD falls to say, 1BTC = 10 USD, presumably some people already in the BitCoin ecosystem would give up adding hash power, maybe even pull out of the whole enterprise. In this case of less hashing power at the margin, what would happen to the rate of increase of the difficulty? I think the difficulty number itself would not fall, but I´m not sure.

Hashing power is typically only added (en masse) when profitability is possible, even if it's long-term. As you've already surmised, a falling BTC/USD rate not only reduces the amount of power being brought online, it also increases the amount of gear being taken offline as well.

As more and more equipment is turned off, the next / expected difficulty will decrease as well, but the current difficulty will stay the same until all 2016 blocks are found. For example, if half of the miners powered off today, the difficulty would still be '3815723799' until the last ~230 blocks (and counting) are solved.


Title: Re: Difficulty vis-a-vis less hashing power.
Post by: Pajeu on March 11, 2014, 06:00:52 PM
Thanks.

I was wondering what could happen if all the Bitcoins stolen from Mt. Gox hit the market. Since the amount that vanished (I read it was close to half a billion USD) is quite large, the selling pressure is considerable. I´m surprised BTC USD exchange rate did not collapse even more. I do not own BTC, but if this move happens and the value drops to less than 100 USD or less, then this could be a very nice entry point. Not so sure if difficulty would fall as much so that mining could be a profitable proposition...


Title: Re: Difficulty vis-a-vis less hashing power.
Post by: ThirdRenaissance on March 11, 2014, 11:41:19 PM
Thanks.

I was wondering what could happen if all the Bitcoins stolen from Mt. Gox hit the market. Since the amount that vanished (I read it was close to half a billion USD) is quite large, the selling pressure is considerable. I´m surprised BTC USD exchange rate did not collapse even more. I do not own BTC, but if this move happens and the value drops to less than 100 USD or less, then this could be a very nice entry point. Not so sure if difficulty would fall as much so that mining could be a profitable proposition...

If you are looking to get into Bitcoin, waiting for 100 USD/BTC is very risky. Some people™ believe we have pretty much seen the bottom already, the usual fluctuations notwithstanding.


Title: Re: Difficulty vis-a-vis less hashing power.
Post by: irrational on March 11, 2014, 11:54:41 PM
Thanks.

I was wondering what could happen if all the Bitcoins stolen from Mt. Gox hit the market. Since the amount that vanished (I read it was close to half a billion USD) is quite large, the selling pressure is considerable. I´m surprised BTC USD exchange rate did not collapse even more. I do not own BTC, but if this move happens and the value drops to less than 100 USD or less, then this could be a very nice entry point. Not so sure if difficulty would fall as much so that mining could be a profitable proposition...

If you are looking to get into Bitcoin, waiting for 100 USD/BTC is very risky. Some people™ believe we have pretty much seen the bottom already, the usual fluctuations notwithstanding.

Agreed.

Having seen Bitcoin go from a few dollars to 18 and back in the matter of months, then the second run up and collapse a year later... To then only go up to 200, and eventually over 1000 before settling back it it's present price at 600, I must say it's a pretty resilient currency.

Trying to time this market is a no-go. Mine for the long term. If I could have back all the BTC I sold for $1, I would :-(


Title: Re: Difficulty vis-a-vis less hashing power.
Post by: ning on March 12, 2014, 09:18:34 AM
The difficulty adjusts, it can go up or down.


Title: Re: Difficulty vis-a-vis less hashing power.
Post by: DannyHamilton on March 12, 2014, 09:48:29 AM
The difficulty will decrease eventually after every 504 blocks.

This is incorrect.  The difficulty changes every 2016 blocks.

The block will be solved longer than 10 mins because there is less hash power. It might take days to solve one block.

If half (50%) of all the hash power in the entire world was removed from the bitcoin network all at once, and no new hash power was added, the average time between blocks would jump from 10 minutes to 20 minutes.

If three-fourths (75%) of all the hash power in the entire world was removed from the bitcoin network all at once, and no new hash power was added, the average time between blocks would jump from 10 minutes to 40 minutes.

In order for the average time between blocks to be a single day (24 hours), we'd have to lose more than 99.3% of all the hash power on the network all within the same set of 2016 blocks.