Is it only biggest pool find the block?

[johnyj]

For example, a pool with 2000GH/s speed maybe calculate out a block in 10 minutes, while a small pool with 20GH/s may take days to calculate out a block

In this case, I just don't see any chance with a small pool since each block will always be found out first by the fastest pool and it's obvious that everyone will run into the biggest pool

Do I understand right?

[WiseOldOwl]

In a sense you are,

It is a lottery, so really technically even if you ran 500 k/hash you could still get it first if your computer guesses it by chance. What you are saying does carry some validity in the sense that a big pool will crack the block in 2 seconds while your small pool is still "laying out their tools" so to say.
The only difference is that at that small pool, when you do crack the block you are getting way way more paid out. With a little luck and timing you can make more at a small pool sometimes (I have, but sometimes it is just to nerve wracking to wait a day or two with no payout), that being said in the end I am using deepbit for convenience and a very predictable payment structure.

To each his own,
Some people just mine on their own cracking a block every month or two (or more even), but they get the whole 50 coins then.

Its a matter of choice, but their is no actual edge you can gain until you get into pool hopping and all that (which is a pain unless you can automate it), and I think pool operators aren't very fond of it but I don't know.

Good Luck and Welcome to the BTC community

[Graet]

http://pident.artefact2.com/  shows blocks found and the pools that found them and heaps more info.
i guess you arent understanding right but a valid question

[johnyj]

Thanks for the explaination

Another aspect I'm guessing: The finding of a block is just a race towards the target, as soon as the target is found, another round of race will start. So if a small pool can not find the block in it's first attempt, then later he will always be slower than the big pool, given that they are using the same scan sequence to find the block

Is this ture?

[Graet]

not really.
its more like a lottery than a race, yes the bigger pools have more "entries" but hey everyone has a chance on every block,be they big pool meduim or small pool or solo miners. bigger pools do get blocks quicker than smaller pools but they pay a much smaller amount/user/block you will wait longer on a small pool but amount/user/block is higher. Over time it should average out statisically assuming 0fee pool etc. Variance is reduced in the big pools increased in the smaller pools.

if it was a race there wouldnt be so many new pools opening daily

[nafai]

given that they are using the same scan sequence to find the block

That's just the thing, they AREN'T using the same scan sequence to find the block. Each miner is given a place to start their search, and the miners use a "nonce" (incremental field sorta) to scan.  Like the pool might say, "ok joe you start at 537165100000" so joe's miner scans 537165100000, 537165100001, 537165100002, 537165100003, 537165100004, 537165100005, etc. While a different miner is given a completely different starting point, and increments it from there via the nonce.

It's like each miner is given a stack of lottery tickets with half the numbers filled in. The miner writes in the remaining numbers starting from zeroes and going up, until it finds the winning ticket. Since the winning ticket is totally random, it doesn't guarantee a faster miner to always win, it just increases his chances. He can go through 100 tickets an hour while you may be able to go through only 10 tickets an hour. But the first ticket you check could be the winning ticket, so even the smallest pools, heck even the smallest SOLO miners, have a "chance" to win -- it's just much smaller than the chances of a large pool winning, because they can check tickets so much faster than the individuals or the smaller pools.

If you solo mine with 1 video card, it will on average with the current difficulty take you months or longer (depending on the card) to find a winning block. However, it is possible that you find a winning block on your first day. But it is very unlikely. In fact, in a situation where your hashing power compared to the total network hashing power is so low (like solo mining on 1 gpu right now), that if the estimated time to find a block is so long (weeks or months or more), the difficulty will go up before you ever find a block, pushing out the date that you are rewarded even further. Remember difficulty is adjusted approximately every 2 weeks.

Thus, people join pools, because when the pool finds a winning block everyone that contributed gets a portion. If you use one of the largest pools, you can get a small reward every hour or even every few minutes. So instead of it taking you 500 days to generate a winning block yourself and getting 50 btc, you simply join a small pool and get 0.1 btc once a day. Or join a large pool and get 0.004 every hour (0.1 btc / 24 hours).

It makes little difference, the math works out the same, whatever your hashing power is that is your hashing power. Whether you join a small pool or a large pool or solo mine just changes the FREQUENCY of your reward, not the amount (excluding pool fees and such, of course).

[Graet]

nafai excellent explanation
I'm going to point people to it

[Bert]

If your video card can solve 400Mhash/second at the current difficulty (1690906) And you were solo mining, it would take you on average 210 days, 3 hours, 24 minutes to solve a block and win the 50BTC (+fees)
(on average 50/210 is 0.24BTC per day)

All that joining a pool will do is feed you the amount that you are due (50 BTC on average every 210 days) in small increments.

So if there were 100 people in a pool each with one 400Mhash/sec graphics card that would mean that one block would be solved on average every 2 days, 2 hours, 26 minutes
So every 2 days you would receive on average  50/100 BTC
(on average  0.24BTC per day)

It there were 10000 people in a pool each with one 400Mhash/sec graphics card that would mean that one block would be solved on average every 30 minutes
So every 30 minutes you would receive on average 50/10000 BTC
(on average  0.24BTC per day)

The larger the pool the smaller the payouts, but they are more often. If you were solo mining the difficulty would probably change several times before you solved your first block (or you could be lucky and get 50BTC +fees on your very first block). This is the main reason that people join pools, it spreads out your payments. You will not receive more Bitcoins than your hardware can solve by joining a larger pool. You are sharing your solved blocks with others and they are sharing theirs with you to smooth out the payments.

Joining the largest pool could cause bitcoin to decrease in value if it gains more than 50% of the computing power.
https://en.bitcoin.it/wiki/Weaknesses#Attacker_has_a_lot_of_computing_power

So I would advise people to join the 2nd or third largest pools, if they need frequent payouts.
https://en.bitcoin.it/wiki/Comparison_of_mining_pools

[codler]

given that they are using the same scan sequence to find the block

That's just the thing, they AREN'T using the same scan sequence to find the block. Each miner is given a place to start their search, and the miners use a "nonce" (incremental field sorta) to scan.  Like the pool might say, "ok joe you start at 537165100000" so joe's miner scans 537165100000, 537165100001, 537165100002, 537165100003, 537165100004, 537165100005, etc. While a different miner is given a completely different starting point, and increments it from there via the nonce.

It's like each miner is given a stack of lottery tickets with half the numbers filled in. The miner writes in the remaining numbers starting from zeroes and going up, until it finds the winning ticket. Since the winning ticket is totally random, it doesn't guarantee a faster miner to always win, it just increases his chances. He can go through 100 tickets an hour while you may be able to go through only 10 tickets an hour. But the first ticket you check could be the winning ticket, so even the smallest pools, heck even the smallest SOLO miners, have a "chance" to win -- it's just much smaller than the chances of a large pool winning, because they can check tickets so much faster than the individuals or the smaller pools.

If you solo mine with 1 video card, it will on average with the current difficulty take you months or longer (depending on the card) to find a winning block. However, it is possible that you find a winning block on your first day. But it is very unlikely. In fact, in a situation where your hashing power compared to the total network hashing power is so low (like solo mining on 1 gpu right now), that if the estimated time to find a block is so long (weeks or months or more), the difficulty will go up before you ever find a block, pushing out the date that you are rewarded even further. Remember difficulty is adjusted approximately every 2 weeks.

Thus, people join pools, because when the pool finds a winning block everyone that contributed gets a portion. If you use one of the largest pools, you can get a small reward every hour or even every few minutes. So instead of it taking you 500 days to generate a winning block yourself and getting 50 btc, you simply join a small pool and get 0.1 btc once a day. Or join a large pool and get 0.004 every hour (0.1 btc / 24 hours).

It makes little difference, the math works out the same, whatever your hashing power is that is your hashing power. Whether you join a small pool or a large pool or solo mine just changes the FREQUENCY of your reward, not the amount (excluding pool fees and such, of course).

how are the scan sequence decided? how big is the chance for 2 solo/pool mining beginning on same scan sequence?

[compro01]

how are the scan sequence decided? how big is the chance for 2 solo/pool mining beginning on same scan sequence?

1. sequentially.  AFAIK, they just increment the extranonce field in the generation transaction for each getwork reply, then the miner brutes their way through the nonce until it rolls over (4.2-ish billion hashes), then requests new work, rinse and repeat until someone finds a block, then start over with a new set of transactions.

2. practically impossible, as the payout address for the generation transaction would be different.  two users in the same pool also would never receive the same work (barring a bug in the pool server software), as it's sequential.

[codler]

how are the scan sequence decided? how big is the chance for 2 solo/pool mining beginning on same scan sequence?

1. sequentially.  AFAIK, they just increment the extranonce field in the generation transaction for each getwork reply, then the miner brutes their way through the nonce until it rolls over (4.2-ish billion hashes), then requests new work, rinse and repeat until someone finds a block, then start over with a new set of transactions.

2. practically impossible, as the payout address for the generation transaction would be different.  two users in the same pool also would never receive the same work (barring a bug in the pool server software), as it's sequential.

ah ok, what will happen if someone gets the "getwork" where the block are and discard "getwork"?