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1061  Bitcoin / Press / 2013-05-09 Forbes Online - 21 Things I Learned Living On Bitcoin For a Week on: May 09, 2013, 09:34:29 PM
The conclusion of Kashmir Hill's re-experiment:

http://www.forbes.com/sites/kashmirhill/2013/05/09/25-things-i-learned-about-bitcoin-from-living-on-it-for-a-week/

Conclusion #1: use Forbes as a blogging platform to put up your Bitcoin address: 10BTC in donations (the article premise wasn't about getting Bitcoin, it was spending them).
1062  Economy / Services / Re: Free bitcoins: Advertise these links in your sig! on: May 09, 2013, 03:46:50 AM
I'm down with adding a ripplescam signature, but I would write it a bit more eloquently. I think their medium-term plan is to get people to transfer them real money to fund their IOUs before they disappear, not just to have a 100% premine coin. Having that message in my signature would make my plan of disposing of those scamcoins on suckers/believers harder though Tongue.
1063  Other / Beginners & Help / Re: Bit Ripple starter giveaway on: May 06, 2013, 07:53:42 AM
Hello everyone,

So I am new to Bitcointalk, haven't felt the need to register (can usually find answers to most of my questions just by searching, although now that I am registered I will likely be getting more involved) but I recently became aware of Ripple via stackexchange.
Be aware that there was a flood of Ripple questions and answers on stackexchange, posted and answered by various sock puppets of opencoin, basically using that site as advertising. Take nothing there about ripple as anyone having a real question, nor interpret an answer being an honest one.
1064  Bitcoin / Bitcoin Discussion / Re: Boycott 0.8.2 on: May 06, 2013, 12:40:28 AM
Yes cause they censored them, either conform to our standards or don't do business anymore.
You sure like that word. I thought I did too ... too bad you're well on your way to destroying its meaning.

What the heck are you talking about? How was anyone censored? Or are you just happily making up stuff? Sad
The only thing censored is by me hitting the ignore button on the OP and anybody else posting stupid stuff here. Plonk!
1065  Other / Beginners & Help / Re: Verification failed, check hardware! on: May 05, 2013, 10:05:30 AM
Yes, if you want a new driver to work, you can ask (with BTC) a miner kernel developer to rewrite the kernel you have chosen in guiminer to support whatever the newest driver and SDK has done to break OpenCL applications. This will benefit few, as dedicated miners already run the appropriate driver to give them not only working but the fastest hashing, and don't use guiminer.
1066  Bitcoin / Mining / Re: The PPNLS system. on: May 04, 2013, 10:10:35 PM
I really don't understand the PPNLS system...  Any suggestions?

Yes, read about the PPLNS system until you understand.

https://bitcointalk.org/index.php?topic=39832.5
https://bitcoil.co.il/pool_summary.pdf
1067  Bitcoin / Technical Support / Re: Can't Sync Bitcoin QT AND No Blockchain File on PC on: May 04, 2013, 06:56:14 PM
2013-05-04 11:50:03 received block 00000000000000ff4aaa342f804a2731bb9f39a784a7f1d86685b35f144cd73a
2013-05-04 11:50:03 InvalidChainFound: invalid block=00000000000000ff4aaa342f804a2731bb9f39a784a7f1d86685b35f144cd73a  height=234477  work=1131399971692442463964  date=2013-05-04 11:47:02
2013-05-04 11:50:03 InvalidChainFound:  current best=0000000000000051e75ec922ddfed09dc3ca0a72f0e8bbc875d7b3fb370d7524  height=234410  work=1128500345104905542838  date=2013-05-04 01:24:51

This is the crux of the problem, your local blockchain database is corrupted and the client can't build on that. It doesn't have the intelligence to try to get the block 234410 again from the network and replace your screwed up version with the correct one.

You will need to delete the blocks and chainstate directories from your bitcoin data directory and attempt to resync the blockchain from the start. Typically this kind of random corruption indicates bad hardware, such as a bad sector on a hard drive or bad math from an overheating or overclocked CPU.
1068  Other / CPU/GPU Bitcoin mining hardware / Re: How many video cards can cool 3-4 Kilowatt air conditioner? on: May 04, 2013, 06:43:33 PM
The amount of heat generated by 1 kilowatt worth of computer (about four 200W video cards + system + 900W power supply inefficiency):

1kWh = 3,412 BTU

So we need 3400 BTU of A/C to remove that much heat generation.

The the next question is how much power will that cooling require. We must look at the the energy efficiency of air conditioning, which is typically given as SEER (seasonal energy efficiency ratio), which we must translate into an actual efficiency measure.

COP = 3.41214/EER

As a low-water benchmark, lets look at a 5000 BTU window AC unit ($110 on lowes.com website)
Specs: EER=9.7, Watts=515 (calculated efficiency multiplier: 2.84)

So this particular model moves 1462W of heat with 515W. A central AC will be more efficient, so 3000kW * 2.84+ = at least 8000 watts (but nothing left to actually cool your house against summer temperatures).

Real miners don't use AC though, why reduce profitability? Put the units in a closed room with a window fan, or in the garage.
1069  Other / Beginners & Help / Re: Still a little confused on Wallets. on: May 04, 2013, 05:10:36 AM
Bitcoin gives you all you can eat addresses for free! Just put keypool=10000 in your bitcoin.conf file, now your wallet has 10,000 pregenerated addresses in it (you'll have a backup that never becomes obsolete).

There are 1461501637330902918203684832716283019655932542976 possible addresses. That's enough for 100x the world's current population to have 1826877046663628647754606040895353774 addresses each.

There will be a maximum of 2100000000000000 Bitcoin base units (a satoshi, or 0.00000001 bitcoin).
Even if every single base unit that will ever be created were put in a different address, there will still be 1461501637330902918203684832716280919655932542976 empty addresses. The chance of you generating an address that has a satoshi in it will be 1 in 695953160633763294382707063198230.

So in other words, it doesn't matter if you create lots of addresses and delete them. If you never use them, the network doesn't even know they exist.

1070  Other / Beginners & Help / Re: How faucets make money? on: May 04, 2013, 02:10:51 AM
Most "faucets" are a scam to get you to click on ads and pay you nothing but unspendable dust. They are pale imitations of the original Bitcoin faucet.

I've personally put about 10000 coins in this faucet, and it still gives out coins, no strings attached: http://tpfaucet.appspot.com/
1071  Other / Meta / Re: BOOKMARK THIS SITE AS https://109.201.133.65, DOMAIN WAS TRANSFERRED on: May 03, 2013, 10:38:58 AM
Domains get hacked often. The problem is if someone hacked the domain registrar account and transferred the domain away, it may be a bit of work to get it back. It's 7pm on a Friday in Japan, 3am in the US. It will take time through the Transfer Dispute Resolution Protocol if the receiving domain registrar doesn't immediately hand it back on the word of registrar #1.
1072  Other / Meta / Re: DNS DOWN !!!! on: May 03, 2013, 10:31:29 AM
better use namecoin

http://explorer.dot-bit.org/n/45362

the namecoin bitcointalk.bit domain points to the wrong IP address, it was bitcointalk.org in mid 2012 https://dazzlepod.com/ip/50.97.137.52/

Whoever created that needs to not forget about updating it.
1073  Other / Meta / BOOKMARK THIS SITE AS https://109.201.133.65, if domain disappears again, etc. on: May 03, 2013, 10:10:28 AM
100 users and dropping, so note this IP, the DNS record was changed for bitcointalk.org away from the forum.

EDIT: site got it's domain back, no need to worry now.
1074  Alternate cryptocurrencies / Altcoin Discussion / Re: Confirmations required for trustable transactions. on: May 03, 2013, 06:42:28 AM
You are wrong. The truth is not a myth. The higher hashrate of Bitcoin does allow it to fend off a particular attacker better than other alt-coins would fare, but then you go into falsehoods.

https://bitcointalk.org/index.php?topic=177308.msg1853377#msg1853377

If you need help, please read the satoshi paper until you understand it. If you can't understand the statistics, you shouldn't foray into starting topics where you claim to answer some question nobody was asking about.
1075  Economy / Trading Discussion / Re: SierraChart bridge - Realtime Bitcoin charts [v0.5] (MtGox, Intersango, ...) on: May 03, 2013, 05:03:35 AM

SCID full history files:
from first trade 07/17/2010 23:09:17, to 04/30/2013 23:59:59 (UTC, tick accurate, precision 2):
(extract to C:\SierraChart\data\ before starting SierraChart)

http://we.lovebitco.in/schart/mtgoxUSD.scid.UTC.7z (18.2MB/182MB)
http://we.lovebitco.in/schart/otherALL.scid.UTC.7z (8.2MB/86.4MB)
Sorry, I forgot to actually upload the "other history" file, it's up now and includes other exchanges and currencies. Funny how nobody dropped me the 411 on the 404.
1076  Economy / Service Discussion / Re: CoinLab suing MtGox for $75 milliion? on: May 03, 2013, 03:01:19 AM
MtGox: we determined it was a bad idea to go through with giving this shady looking individual the banking credentials and passwords of non-consenting users, especially since he got into the scamcoin business.

Me: Hey coinlab, where can I serve you notice? Me and 1000 others will get default judgements against your "company" in every state of the union, even before your lawsuit with MtGox is dismissed in summary judgement.
1077  Bitcoin / Development & Technical Discussion / Re: 234078 Longest block to solve yet? on: May 03, 2013, 02:20:43 AM
It's not a bell curve, the probability density function of an exponential distribution looks like this:



Note that the average block time is 10 minutes (1/λ), but 50% of the blocks are less than 6.93 minutes (the median ln(2)/λ).

The reason that it makes no difference is: whether the geometric distribution (which counts individual hashes) is calculated for difficulty 1 or difficulty 10000000, the probability of a quantile (such as calculating the probability of a block taking 100 minutes) is the same within several decimal points. In fact it is already identical to the exponential (continuous) function with three digits by difficulty 1, higher difficulty just makes the density function of geometric converge to exponential with even more digits of identity.

http://math.stackexchange.com/questions/93098/how-does-a-geometric-distribution-converge-to-an-exponential-distribution

Here's a monte carlo simulation of a geometric distribution density, the red line is exponential:

See how much like the exponential it is? This example shows a 0.1 probability; Bitcoin's current probability is 0.0000000000000000231. With a lower probability,the steps disappear and the distribution converges to exponential.

So the answer is: the probability of a block taking 62 minutes (given a constant hashrate equivalent to difficulty) is 0.2029%, whether the difficulty is 1 or a billion.
1078  Bitcoin / Development & Technical Discussion / Re: 234078 Longest block to solve yet? on: May 02, 2013, 09:39:25 PM
My stats are a little rusty, but as far as I see, it doesn't, it goes up.

Hashing is Bernoulli trial, either you beat the target or you don't. That gives mining a geometric distribution, and so the variance (in number of hashes required) is (1-p)/p2. The re-targeting algorithm tries to keep the hashrate directly proportional to 1/p, so the variance in time quadratically increases with the hashrate. Right?

I guess the phenomenon above was a much higher variance in hashrate because of people turning their computers off at night, whereas now the variance is greatly reduced due to increased numbers and because miners tend to keep the gear running 24/7.

Only 'technically', on a very small scale, is the variance different. In reality it is unobservable at different difficulties.

Hashing is typically modeled as an exponential distribution, a continuous series, however it is actually a geometric distribution. The probability is so low though, that the R statistics package fails to compute due to overflow errors with statistics on much more than difficulty 1.

The variance is given for a geometric distribution as:



You can see that for extremely small p (probability of one hash finding a block), the top numerator approaches 1, becoming insignificant compared to the p2.

The high block times around 20000-30000 has something to do with the satoshi miner and others not making much hashes during that time, there was much less than difficulty 1 worth of mining being done. I could eliminate the first year of Bitcoin to get a better list of long blocks, long due to variance rather than low hashrate.
1079  Bitcoin / Development & Technical Discussion / Re: DNS and wallet addresses on: May 02, 2013, 02:22:05 AM
much harder to forge:

http://explorer.dot-bit.org/n/74491
1080  Bitcoin / Development & Technical Discussion / Re: why not measure difficulty in bits? on: May 02, 2013, 01:39:04 AM
The difficulty is actually in bits, the field in the block that contains it is called bits, which is decoded into the target.

Here's the current target, a hash has to be smaller than this number:
00000000000001AA3D0000000000000000000000000000000000000000000000

or in binary:
0000000000000000000000000000000000000000000000000000000110101010001111010000000 0000000000000000000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000000000000000000 0000000000000000000

The difficulty is easy to comprehend and is what is presented to users. What you are proposing is harder:

>>> math.log(2**256/int('00000000000001AA3D0000000000000000000000000000000000000000000000',16),2)
55.26448364017038

What  "bit" difficulty would be 10% harder?

>>> math.log(2**256/((int('00000000000001AA3D0000000000000000000000000000000000000000000000',16))/1.10),2)
55.40198716392032

Satoshi got it right. Not everyone uses Python as their calculator. Use a base difficulty, where 1 = 1 block find per ~4295032833.0 hashes on average, and higher difficulties are multipliers of that.
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