Bitcoin Forum

Just thought I would toot my horn, and brag that I solved 7 blocks yesterday on my mining cluster of 8 5970's.

Oddly, 4 of the blocks were solved by a single 5970.

On average, at the current difficulty of 55000-something, I'm supposed to be solving less than 2 per day.

I know that a lucky day is occasionally to be expected - it's the nature of randomness - but after plenty of days of less than average results, it's nice to get a day of way more than average to balance it out.  And I suppose this thread is for the benefit of discouraged miners who are mining away and questioning their results, if they're not lucky at first.

I have three mining rigs, two 5830, one has yet to solve any blocks, my 5870 has solved 4.  Here is the kicker....

My 2.4ghz core 2 duo on 1 processor (780kh) solved one after being on for 5 days.  It should do that every 1000 days or so? 

The beauty of randomness...

You know, it is theoretically possible (however very very very very tiny probability) to solve 30 blocks in one day on a machine doing 10khash/sec.

But i think that winning a block on core2duo after 5 days, qualifies one for playing national lottery ;)
 

You know how prime numbers tend to group together?  I wonder if it is truly random...

It is random as long as it depends on human actions.

Human actions are generally very random. So it is random, because transactions are random enough. Unless of course, transaction data is not included in the hash, but AFAIK it is.

FWIW, if you average 2 blocks/day, your probability of having at least 7 in a given day is 0.45%. Of course, if you run the setup for several days, your chance of it happening in one of them is much higher.


Hm? The transactions that occur have very little to do with your probability to find blocks. It depends on whether your PRNG generates a right nonce. To the extent that PRNGs can be considered random, so is block generation.

If transactions are also hashed, then they do have an influence on randomness.

AFAIK, the candidate block changes every time a new transaction is to be included in it, so it changes the "source" the algorithm has to hash from.

Hmmm... I'm interested in buying this 5970. how much?

The frequency of finding blocks is an example of the Poisson distribution. Here is a good, simple page about it:

http://stattrek.com/Lesson2/Poisson.aspx (http://stattrek.com/Lesson2/Poisson.aspx)

(no, that doesn't say star trek)

Here is a calculator: http://stattrek.com/Tables/Poisson.aspx (http://stattrek.com/Tables/Poisson.aspx). You plug in the number of blocks you should have gotten in an interval, and the number of blocks you actually did get (or think you might get). It will tell you the probably to get that many blocks, or more, or less.

I hate you!

Just kidding. Congrats!

They have an influence on whether you actually found a block or not. If at some point my PRNG generated the number, say, 523789, this will or will not lead me to a valid block depending on the transactions. But they don't change the probability or statistical properties of generation. If the PRNG is random, then the transactions can't make generation any more or less random. For example, even if there are no transactions at all, generation will still be random with the same expectation.

You assume that the software random generator has enough entropy, but it does not.
That is only pseudo-random, and that's why i was saying that transactions add more randomness by adding more entropy to the pool.

I disagree, for this purpose the PRNG doesn't need a lot of entropy to be in practice indistinguishable from truly random. This can be verified by experiment - generate for a test block chain with no transactions, and see if any deviation from randomness can be found.

If more entropy was required then yes, I guess the transactions could help a little.

Well how do you know if youve successfully resolved a block ? Been mining for almost a week with 400KH/s but still nothing in my client Bitcoin client @.@

If you are getting the hash rate readout on the miner itself and it is changing every so often it is working.  I have a 200kh/s miner that has not hit ever (14 days?).  Difficulty is going up in an hour or two and it is going to get worse.

Yeah the hash rate is fluctuating around :P , I'm mining solo but seem to be this is getting now where, crap >.>

Ps: anyway if I get my first block, it will be display in the bitcoin client right ?

Has such experiment been ever done by anybody ?

Just in case this question is directed to me, I didn't mean to suggest I know of the experiment having been made, only that I have little doubt what its results would be. I am also interested to know if someone already did it.

Truecrypt did experiments on their alrogithms, and the result was around 70% entropy.
I seriously doubt that any no-human-interaction algorithm can do much better.

Again, I am speaking specifically about frequency of generating blocks. Standard PRNGs don't generate high-quality randomness, but generation doesn't need it either.

Plug your hash rate into the Bitcoin Calculator to see how often you can expect to find a block. 400 kh/s will take over two years. That's if difficulty doesn't go up.

http://www.alloscomp.com/bitcoin/calculator.php (http://www.alloscomp.com/bitcoin/calculator.php)

400kh/s, Average 9469 days, 4 hours, 50 minutes

~26 years

Based on travex's other posts, I think he really meant 400 MH/s.

Yeah my bad mate , actually its 400Mh/s lol =D