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261  Bitcoin / Hardware / Re: Are current generation ASICs SHA256(SHA256(x)) implementations? on: May 15, 2013, 05:11:07 PM
That doesn't tell me if the ASIC hardware does SHA256(SHA256(x)) or if it is SHA256(x) twice.

Yes it does.  You must have missed the part where it said  "dhash(a) = sha256(sha256(a))"


Okay let me rephrase my question, is it possible for the ASIC hardware to just do SHA256(x) instead of SHA256(SHA256(x))?
262  Bitcoin / Hardware / Re: Are current generation ASICs SHA256(SHA256(x)) implementations? on: May 15, 2013, 05:03:37 PM
That doesn't tell me if the ASIC hardware does SHA256(SHA256(x)) or if it is SHA256(x) twice.
263  Bitcoin / Hardware / Are current generation ASICs SHA256(SHA256(x)) implementations? on: May 15, 2013, 03:40:35 PM
Does anybody know if they are explicitly double SHA256, or if they simply run the SHA256 twice.
This is important because it also denotes their usefulness outside of Bitcoin.
264  Bitcoin / Mining speculation / Re: New ASIC project was announced in Chinese forum, 200T in Sept. on: May 15, 2013, 04:54:43 AM
If that's true, then GPU mining without free electricity will be dead by the end of Winter 2014 (to account for those who try to heat their houses with GPU miners).
265  Other / Beginners & Help / Re: Can a massive drop in hashpower make bitcoin slip into a downward spiral? on: May 15, 2013, 04:31:50 AM
If an attacker was able to gain 50% hash power, they could quite possibly get upwards of an entire cycle's worth of coins.
First they put that 50% hash power into the network gradually raising the difficulty (and mining at the same time), when it adjusts the difficulty, they pull their power.
They wait the 4 weeks, then when the difficulty which is now probably 25% slower, they start mining again, and they have 25% advantage still. Which means they net a bunch coins again.
The trick would be achieving this attack for under half a million USD which would be about what they got in coins after doing this.
266  Bitcoin / Mining / Why is there so much variance in the mining? on: May 15, 2013, 04:17:57 AM
It seems like every time I check blockchain.info there are groups of blocks found within 30 minute blocks, and then there are times when it takes 30 minutes for a block to be found. While it still averages (according to blockchain.info) to be under 10 minutes per block, it certainly isn't that consistent.

And will this variance just get worse as the difficulty rises?
267  Bitcoin / Development & Technical Discussion / Re: Hacking the fork on: May 14, 2013, 08:17:56 PM
It would be interesting if somebody did this to all non BTCGuild mining pools just to push their effective hashing power to over 51% to cause trouble. But this could be very easily fixed by forcing the miners to use system time.
268  Bitcoin / Mining speculation / Re: AMD stock going up, due to alot of people buying radeon cards for mining? on: May 14, 2013, 03:01:42 AM
Wasn't there a rumor going around, that intel is/was gonna buy AMD?

If true, that could be the reason.
Don't think the government would allow that. That would give Intel a monopoly on desktop processors.
269  Bitcoin / Development & Technical Discussion / Re: 32Bit timestamps in the block headers? on: May 12, 2013, 09:34:26 PM
Why would Satoshi (group or indiv.) use 32 bit timestamps which would overflow before the last coin was designed to be minted?

The fix is simple, just up it to 64bit unsigned integers to represent the date.

This problem will rise in 2100+ A.D. only.
Which is 34 years before the reward is due to be zero. This is going to be a problem eventually, so why not fix it now?
270  Bitcoin / Development & Technical Discussion / 32Bit timestamps in the block headers? on: May 12, 2013, 09:11:21 PM
Why would Satoshi (group or indiv.) use 32 bit timestamps which would overflow before the last coin was designed to be minted?

The fix is simple, just up it to 64bit unsigned integers to represent the date.
271  Bitcoin / Hardware / Re: How efficient will ASICs get? on: May 12, 2013, 02:55:54 AM
It is my understanding that the current generation of ASICs all get around 100MH/joule give or take a few million hashes. While that is upwards of 20x more efficient than GPU mining, how much more can be pushed out? Given we understand exactly the operation needed, does anybody know what the minimum amount of energy that could possibly be expended to perform SHA256?


Do you know what Moore's law is?


Something that hardly applies to bitcoins.  Makes sense for the microprocesser market worth tens of billions of dollars (maybe into the hundreds of billions)

When your NRE for an ASIC runs several million or tens of millions of dollars, you have to make a financial decision if it's worth the investment, risk, and design/lead times for a marginal improvement over what already exists

Look at it this way : Asic Miner is a 100% capitalist, maximize profit type of organization.  They used, what, 110 or 130nm node for their fab?  You could get much better power efficency and hashrates with a smaller process, but it's far more expensive and complicated.  They have no plans to change node, they're bringing 262 THash/sec online with their 110nm in the next 3 months.  A massive investment that shows they're dedicated to what they've got.

You really believe they're making 26,200 blades?
Why wouldn't they? They stand to not only increase the hashrate, but effectively ensure their product will be bought at the same time.
For every blade they sell, another one will be sold to keep somebody else in the mining game.
272  Bitcoin / Hardware / How efficient will ASICs get? on: May 11, 2013, 07:27:46 PM
It is my understanding that the current generation of ASICs all get around 100MH/joule give or take a few million hashes. While that is upwards of 20x more efficient than GPU mining, how much more can be pushed out? Given we understand exactly the operation needed, does anybody know what the minimum amount of energy that could possibly be expended to perform SHA256?
273  Bitcoin / Mining speculation / Re: Minimum sustainable mining efficiency. on: May 07, 2013, 01:32:14 PM
Hmf. You are absolutely correct

I was confusing the different numbers, and looked at power cost as revenue and revenue as surplus Huh

Oh the humanity Tongue
If only it worked that way, we'd all be rich Smiley
274  Bitcoin / Mining speculation / Re: Minimum sustainable mining efficiency. on: May 07, 2013, 01:47:24 AM
Depends on the accuracy of this calculator http://www.bitcoinx.com/profit/

Diff - 300,076,293
Mhash - 5000
Conversion rate - 2
power - 30

Says it will give a profit of $0.02/day
It says you'll get a revenue of .02$ per day, you have to factor in your power costs.

Quote
Coins per 24h at these conditions   0.0084 BTC
Power cost per 24h   0.11 USD
Revenue per day   0.02 USD
Less power costs   -0.09 USD
System efficiency   166.67 MH/s/W
Mining Factor 100 at the end of the time frame   0.00 USD/24h@100MHash/s
Average Mining Factor 100   0.00 USD/24h@100MHash/s
Power cost per time frame   9.86 USD
Revenue per time frame   1.44 USD
Less power costs   -8.42 USD
You'll lose money overall.
275  Bitcoin / Mining speculation / Re: Minimum sustainable mining efficiency. on: May 07, 2013, 01:30:21 AM
You forgot ASIC
Yeah, hidden deep within my text is the subtle idea that GPU mining is dead, due to it being less efficient.

Smiley

I calculated that a 5GH ASIC at 30W would still be running with a difficulty of 300mil and a BTC price of $2, and even make a tiny profit.
Are you sure? By my calculation you'd need just over GH/J at that difficulty and price assuming .15$ per kwh. 5GH at 30W is 166MH/J
276  Bitcoin / Mining speculation / Re: Minimum sustainable mining efficiency. on: May 07, 2013, 01:13:30 AM
You forgot ASIC
Yeah, hidden deep within my text is the subtle idea that GPU mining is dead, due to it being less efficient.
277  Bitcoin / Mining speculation / Minimum sustainable mining efficiency. on: May 07, 2013, 01:08:38 AM
I've done some math, and come up with a formula to determine the absolute minimum sustainable (break even) network efficiency (in terms of Hashes per joule).


This basically gives the minimum efficiency that would be required to run the network if it was a single person mining and they got all the coins. So for mining to be profitable you'll need to be a tad higher than the given efficiency(to account for pool fees and luck), but it does shed light on the future of mining.

For price = .15$, difficulty as 10076292.88, reward at 3600 coins per day, and exchange rate at 110.
655714 Hashes per joule.
Which is a little less than half of what blockchain.info estimates the efficiency to be at (1.5MH/J).

Now if we fast forward  to the end of the year, I personally believe we will see 50M difficulty (350TH/s+), I also believe we will see a stable 200$ per coin, so at .15$ per kwh results in about 1.79MH/J, which cuts out some GPU miners already.
.10$ per kwh: 1.19MH/J
.05$ per kwh: 596KH/J
Obviously, cheaper electricity lowers the efficiency needed.

But what this formula really lets us know is the long term viability of the network itself. Right now, to currently survive off transaction fees alone (144*(500*.0005)) my estimate is that on average you get 500 paying transactions per block, and at the default fee, it amounts to 36 btc per day. At the current rates...
65.5MH/J are required to break even.

This makes it apparent that cheap electricity will be required to
Just some food for thought.
Now does anybody have any thoughts on this?

EDIT: I really hope my math is right, or I'll sound really stupid.
278  Bitcoin / Bitcoin Discussion / I thought the idea was to prune spent outputs, not block new transactions? on: May 05, 2013, 09:49:43 PM
I thought the general consensus on blockchain size management was to prune spent outputs from the earlier blocks, so that the blockchain's size would be related to transaction volume instead of a history.
279  Economy / Service Discussion / Re: BFL's site is incredibly amateur... on: May 03, 2013, 03:12:22 AM
While, it's good of you to alert people. I think you should have alerted them instead of publicly outing their exploits as soon as you found them.

But hey, if your tactic is to get professional penetrators to cause a stir, more power to ya. I just wouldn't have done it this way.
The fastest way to get anything fixed is public outing.
It's fine and dandy to believe that, except by outing this, you've put other people's information at risk. Let's say somebody does get into BFL's systems, what kind of information do you think they have stored on their servers? Information that somebody who has a vendetta against bitcoin could put to good use, such as the mailing addresses of tens of thousands of people. Not to mention any related payment information.
280  Economy / Service Discussion / Re: BFL's site is incredibly amateur... on: May 03, 2013, 02:12:58 AM
While, it's good of you to alert people. I think you should have alerted them instead of publicly outing their exploits as soon as you found them.

But hey, if your tactic is to get professional penetrators to cause a stir, more power to ya. I just wouldn't have done it this way.
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