That configuration ranks up there as far as being on the high end of Mhash/J.  A whole lot of hardware is probably at a third less.   And few care to mine just to break even -- unless the waste heat serves a purpose as you described.

 - http://www.bitcoinx.com/profit/

The number of people whose marginal electric rate is $0.07 per kWh or less is a pretty small number.

Or you put in a lowball bid and just wait for "8 O'clock Charlie" to strike.

Incidentally, this works both ways.  We've seen buying right before the bell that pushes the clearing price up above market as well.

Liquidity is the solution.  And these type of profit opportunities are just what brings more liquidity.

Well, there's no such thing as "rollback".  There is the Finney attack which is to include (but not broadcast) a transaction that spends funds to another address controlled by the miner.  Immediately when that miner (or pool operator) solves a block, hold the block and place a bet with SatoshiDICE with the same coin.   If it wins, toss the mined block and collect the winnings.  If it loses, broadcast the block. and get the losses back.  Of course, the problem with that is that it is pretty easy to detect that it is happening.

So a mining pool operator could get away with it until SatoshiDICE (or anyone else looking at the double spends) points out which pool operator is doing this and thus that pool loses hashing capacity as miners move on to other pools that don't use their customer's hashing strength to cheat bitcoin businesses.  (and, more importantly, having "bad luck" by throwing away blocks you as a pool miner had shares for, if payouts are of that category).

Also, as my post just one above yours mentioned, there is an expense to carry this out and a way for SatoshiDICE to mitigate if it happens enough to worry about it.

[Edited to clarify why miners won't stay with a pool that would cheat here.]

There have been reports of people having a good experience using CurrencyFair in conjunction with an exchange.  With CurrencyFair, you transfer money (bank wire push) from your bank account to  CurrencyFair, then convert to a destination currency (e.g., USD) and then send the funds as a wire elsewhere.
 - http://en.bitcoin.it/wiki/CurrencyFair

There've been a few reports that this works with Mt. Gox, though others have said that wire transfers to Mt. Gox (in this case, coming from CurrencyFair) must be in the name of the accountholder so who knows.  This may work with other exchanges as well though.


Yup.  It's just a rock (and shadow).

At the current levels of exchange rate and difficulty, yes, there is currently too much GPU hashing capacity to be supported by 3,600 BTC at $12.50 per BTC.


Was 24 Thash/s necessary to protect from 51% attack?  If bitcoin only had 12 Thash/s would it have been p0wned by an attacker by now?

Unlikely. 

It will consolidate for a bit here. 

If ASICs weren't "real soon now", miners would be buying up FPGAs to replace their power-hungry GPUs.  But with ASICs around the corner, nobody is buying an FPGA right now.

While GPUs started out being people using their existing gaming GPU, it quickly become a commercial endeavor.  Since a small-time miner would hit limits for power and heat, only those who could expand were the larger GPU farms where the cost of new electrical and heating could be justified by it adding such large amounts of hashes.   The efficiencies favored a smaller number of larger players.   

Because FPGAs were more efficient, the electrical capacity wasn't reached as easily.   This helped to distribute the hashing capacity to a wider group again.

ASICs will likely cause distribution to spread even further.

So essentially, the "energy hog" property of GPUs actually worked against decentralization.  If the hashing capacity drops, it is coming nearly entirely from GPUs so the mix of GPUs and FPGAs will show GPU dropping and FPGAs growing (on a relative basis), but both are done when ASICs ship from multiple manufacturers.

Yup, I guess I should have qualified my statement by saying payouts for wagers that end up being double spends don't cause a loss to SatoshiDICE.

We know that to do that type of double spend (using the Finney attack) is expensive. And a mitigation should SatoshiDICE start to see these occur, is to delay disclosing WIN/LOSS status long enough so that a financial loss is ensured for anyone attempting this strategy.

Incidentally, there's another recent thread with some overlap:

How do we deal with an internet blackout?
 - http://bitcointalk.org/index.php?topic=128702.0

Sounds like Free Network Foundation.   They have a nationwide license for 3.6 GHz  (for backhaul of a Kilometer-wide range).
They are operating a mesh in Kansas City right now.
 - http://commons.thefnf.org/index.php


Incidentally there's another recent thread with some overlap:

Bitcoin + Decentralized Internet = ?
- http://bitcointalk.org/index.php?topic=127849.0

Now I'm confused.  You said the 99 went in transaction 724d1caf9cc4302d02564908fcbd1d47878732b6eb4da818a3495709d595944c:
 - http://blockchain.info/tx-index/34640934/724d1caf9cc4302d02564908fcbd1d47878732b6eb4da818a3495709d595944c

So from that transaction I see that the 1 BTC went to 1NNdZiBH3yLsBSxrdVrJRptaj99hQwvbKy:
 - http://blockchain.info/address/1NNdZiBH3yLsBSxrdVrJRptaj99hQwvbKy

But that 1.0 BTC amount hasn't been spent since that transaction.  And that address later had another 99 BTC sent to it, so it now holds 100 BTC.

Have you tried launching the Bitcoin-Qt from the command line with -rescan?

 Bitcoin-Qt -rescan

Heh, nope.


If the GPUs are providing needed heat for the winter, maybe springtime.  Or earlier, especially with the noise.

Just like nobody messes with CPU mining anymore, once 100+ Thash of new capacity comes online, those GPUs won't be doing any good even with free electricity.

Now there could be continued life with CoinLab's HPC effort ... especially for those with a low cost of electricity.

LOL.

Just in case anyone else is unaware of how SatoshiDICE works, the payouts include coin from the original wager.  This is the innovation that allowed them to do instant payouts without having to wait for confirmations.  From another thread:

Heh.   Don't do it. lightlord or at least ask for like 100:1 odds.

[Edit:  TradeFortress ... at least make it look somehow fair.  "If not, I give you my entire wallet in 72hrs."]

FFS, Would you just relax.

This is not the first time this happened.  Every transaction on SatoshiDICE that is a WIN eventually gets paid.    This is provable using the blockchain.

Your transaction confirmed.  It shows WIN.  You will get paid, just not right now apparently for whatever reason.
 - http://satoshidice.com/full.php?tx=a2dde18101ec3485fecb0d7b717371e1a61ff2ae2dff96002cf3683bde545b30

Incidentally, wagers that are double spends don't cost SatoshiDICE a thing, because even if they sent a payout for the WIN already the payout will not confirm either as it too will be a double spend.  And it is then no different from having never made a payout at all.

When these situations happen with SatoshiDICE, they can take a day or two to resolve.

There's nothing you can do but wait.

Even when GPU mining was profitable this was not recommended because it is so easy to harm either the GPU or the laptop with mining with this form factor.

After halving occurred a few days ago, unless you pay less than about half the average rate for electricity you are not going to be able to mine for profit on a GPU.  

The average electric rate is $0.15 per kWh, so if your cost of electricity is 0.075 per kWh or more, mining on a GPU now (and going forward, most likely) is a money-losing proposition.

A.) If you are transferring Linden dollars from someone else, then yes -- you must register an avatar to receive them before you can send them to VirWoX to convert to BTCs.

B.) If you already have Second Life account and just want to sell your SLLs through VirWoX, then you update your VirWoX account with your avatar id, and then use the VirWox terminal in-game to transfer the SLLs to VirWoX.

C.) If instead you are first buying SLLs from VirWox and only using them to buy bitcoins, then it is all handled within VirWoX's ledger.  i.e., SLLs never left VirWox's account.  It is just a book entry.  And thus you don't need to touch Second Life or register an avatar.

And the first couple of times you expressed your concern, you didn't.

There seem to be extended delays at SatoshiDICE.com right now, from looking at their site:
 - http://satoshidice.com/lookup.php?tx=&limit=1000&status=ALL

If you are hoping for fast payouts, you might want to not make any new wagers until SatoshiDICE staff gets things resolved.

Looks like there are some significant delays with ALL many wagers made on SatoshiDICE right now:
 - http://satoshidice.com/lookup.php?tx=&limit=1000&status=ALL

Does a bitcoin exchange have that same level of responsibility?
 - http://www.reddit.com/r/Bitcoin/comments/12j9gi/i_just_had_715_stolen_out_of_my_mt_gox_account/

Operate infrastructure without chokepoints.

 - http://www.theFNF.org

You are allowed to use those for the purpose of converting the school's electricity into bitcoins for personal financial gain?   Have you gotten permission (in writing, to be safe).

As far as whether or not it is worth it even if you get permission is another topic.

Are you aware of the performance levels the ASIC mining hardware is being promised to deliver?