That's what I thought, so yesterday I contacted Qbix via the DOSBox forums. He has now replied to my mail, but was less than enthusiastic. I think this may be a matter of a simple misunderstanding of my message, and thus solvable.

Most people will think that when 800 days elapse they are guaranteed to find a block. This will only lead to frustration. Even if we tell them it's random they'll underestimate its variance. And there's no point in this, CPU mining with a pool is worthless enough, no one in their right mind would want to do it solo.

Wrong answer, or wrong question? 2^160 = 1.46*10^48, 0.5^160 = 6.84*10^(-49), and 1 in 1.46*10^48 is 6.84*10^(-49).
Wolfram|Alpha, by the way, fails spectacularly to parse "1 in 2^160" in the sense we mean here.

Sure! Welcome to the forum. I guess a community revolving around a pseudonymous currency doesn't much value an introduction section. But there's a range of ideologies or lack thereof here so don't be afraid if you're not into anonymity. Feel free to tell us about yourself or to ask questions.

I had similar occurrences, also on a 5870 (and Windows XP). The most recent was that I left my miner (poclbm GUI) running, and when I checked it some hours later the hashrate was 140 MH/s. Restarting the OS restored the normal hashing rate of 315 MH/s. Any ideas about the cause of this?

Yeah, I think that's what they're trying to do with Bitcoin.local.

Yes, email sent, but still no response.

I've done some calculations, assuming for simplicity that the contract starts at a difficulty retargeting point, and found that the absolute maximum you might be required to pay with this contract is equivalent to 278.8 days at current difficulty, which is 4065 BTC. This is achieved if retargeting occurs at 34.6, 65.0 and 86.0 days. If you're serious about this, you may want to secure this amount in advance.

If there's sufficient interest in this kind of calculations, I might write a post about it.

Doing only that is a bad idea. I'm not going to take a plane to wherever you're located to give or take some cash, or trust that cash in the mail will reach its destination. As an additional service this is of course wonderful, though not as important IMO.

People will do <$1 transaction for testing, not on a regular basis, so it won't be thousands a day. Also, mndrix says he uses PayPal's mass payment API which doesn't require fees, if you don't you should look into it.

Terrible ideas.

When I started out with Bitcoin, one of my family members asked, "But that's just play money, right? You can't convert it to real money". I said, "Sure I can! Here, watch me - " and thus began a long process of frustration, tearing my hair out, digging in forums and sending furious emails, until I finally found CoinCard. Most people - and even more so, businesses and organizations - need to be able to trade bitcoins for currency they are familiar with before the whole thing is real to them. And it needs to be downward scalable, because they won't invest in Bitcoin (in the general sense of the word) before they accept it.

People always talk about how PayPal is inferior to some services I had never heard of and that nobody accepts. But PayPal is ubiquitous and international. I already have an account because it's useful to me, and I know that funds I receive to it I can withdraw to my local bank account. Converting BTC->PPUSD is an extremely important service, and CoinCard provides it very well. When I suggest accepting bitcoins to organizations, I will recommend that they use it, not go to the marketplace and look for people willing to relieve them of their bitcoins for a service they might happen to need (or go to MtGox and try to figure out how to withdraw USD from it).

PPUSD->BTC is less important IMO, and it is already served by CoinPal and the MtGox PayPal exchanger.

So what I'm trying to say is, it's great that you started this service, competition is good. And please consider relaxing the 10 BTC minimum. People need to be able to try it out with small amounts, even 1 BTC is limiting. I'm sure what you'll lose in transaction fees will pay for itself in attracting new business.

Good luck!

That's exactly the same as far as probability is concerned. Also, unless I'm misunderstanding something about the protocol (which is likely), the 160-tosses version I described better represents the scenario I gave, of trying to replicate a specific address.

I assure you that behavior like that of users ben bernank and Greenspam above is very rare here. I'm sorry you were exposed to this. I think you'll enjoy these forums, most of us are very reasonable people.

I don't have any input on your original question.

Give it to me. I could use an extra degree.

It's just common sense, really. A Bitcoin address is just a 160-bit number. If you want to randomly generate an address and have it exactly match some other address, you need every bit to match. Every bit is like a coin toss, so it's like 160 tosses. The probability for that is 0.5^160 = 6.84E-49. I didn't examine the calculations for the larger 9.7E-29 figure (equal to 93 tosses) but it's probably the chance to succeed in one of a large number of attempts.

Google PageRank is a perfectly technical term which does not mean "position in Google search results". You can find the PageRank of a site here, for example, and there are also browser addons for that.

Dear god, no, that's completely wrong. You did (1/131M)/(9.7E-29), when it should be log(9.7E-29)/log(1/131M) = 3.45. So it's like winning the lottery 3-4 times in a row.

Again, no. It's like getting 93 heads in a row: log(9.7E-29)/log(0.5).

The point remains, though. That's an extremely small probability. Collisions aren't going to happen and there's no need to be concerned about it (assuming the PRNGs used are half-decent. They don't need to be good).

Thanks . Raulo, who wrote that guide, has already linked to it.

I appreciate your advice, but I made my own assessment of pros/cons and I still think it's worthwhile. Anyway, calibrating my projections is one reason I'm waiting with this.

For my general-purpose computer, yes, of course. I also bought a 5870 to mine on it. But I'm talking here about building a dedicated mining rig.

Thanks! The embarrassing part is that I think I saw this earlier, but have since forgotten and didn't find it in searches.

5 BTC sent, though I think still this should all be consolidated into a nice wiki page.

I couldn't figure out if this contains info on configuring the Bitcoin daemon to accept RPC connections. I barely managed to get that to work on my Windows machine...

I hope this will work, I actually have some time until I go through with this. I'll ask if I encounter any problems.