Quote from: ribuck on November 28, 2010, 02:07:22 PM

Quote from: RHorning on November 28, 2010, 07:11:33 AM

... if you happen to be requesting hashes where you've received a couple dozen reduced hashes and then the network has a huge spike in difficulty. This is a potential liability issue so far as the "owner" of the hash farm server is concerned, as it would substantially impact the "profit margin"

Sorry, you misunderstand. The server operator only pays out to easy hashes that were submitted for a block that is won. There's no payout for easy hashes that were submitted for a block that someone else generates.

The difficulty can't change in the middle of a block. It always changes at a known time, and you always know exactly what the difficulty is, so there's no risk here.

I guess I do have a misunderstanding here, although there is another side effect in terms of hashes being made for blocks that aren't won. Clearly that is a form of "proof of work" and at least represents effort being contributed to the pool and I guess I'm not convinced that "good faith efforts" to perform a hash ought to go unrewarded, but that clearly would be a part of the "rules" of the pool. As long as everybody is agreed ahead of time and this point is clear, I don't see huge problems in that regard.

However, excluding potentially successful hashes would have the tendency of driving out weaker participants. I also think it would introduce a significant bias statistically toward the server operator as the number of successful blocks "won" compared to successful partial hashes for the current block would be considerably less than the 1/40 ratio. I envision a situation for pooling groups like this with more mundane clients where it would be common for only one person to get rewarded for a successful block hash using these rules. Or to put it in another context, on average there would be no benefit at all for somebody to join into such a pool with such rules where they would simply be more effective generating coins with the network itself.

Again, I'd like to see some statistics of this in practice, as all I'm making here is a conjecture based upon my own understanding of statistics.

Quote from: satoshi on November 28, 2010, 04:03:30 PM

New users wouldn't really even need the Bitcoin software. They could download a miner, create an account on mtgox or mybitcoin, enter their deposit address into the miner and point it at anyone's pool server. When the miner says it found something, a while later a few coins show up in their account.

Miner writers better make sure they never false-positive near-hits. Users will depend on that to check if the pool operator is cheating them. If the miner wrongly says it found something, users will look in their account, not find anything, and get mad at the pool operator.

In terms of verifying a "near hit", it would be verified against current rules but for a reduced difficulty. There is a statistical probability that such a near hit may even be a successful hash. Some "client" of the coin farm who is consistently reporting "false positive" on a hit would be almost instantly verified as such and be considered a troll where certainly they would not be rewarded or even recognized, and it would be in the interest of the server operator to simply blacklist those clients altogether or at least dump the connection.

Still, I get what you are saying here Satoshi in terms of the miner writers not producing something which produces these false-positives. This is something that ordinary economic theory would resolve so far as those mining clients are concerned. Somebody who comes up with a software package which only contains the communication protocol but doesn't produce results would be quickly discarded by its users.

I love the idea here that somebody could install a miner on their computer without even installing the Bitcoins software itself. This implies that perhaps you could even put a miner on a cell phone or some other device if you cared (but of course chewing up battery life as a consequence). It does open up a whole bunch of potential ways to mine coins and expand the pool of potential CPUs engaged in this activity.