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Title: Block non-convergence soon? Post by: mimarob on December 26, 2010, 10:36:49 AM hello!
am I rightly informed that the nonce is only 32 bits? Does this in turn mean that there are "only" 2^32 or about 4 billion (4E9) combinations to try for each block? If so, then when network hashing capacity reaches 4 000 000 kHash/sec the block would be solved in one second on average? This contradicts the onlīne hash-rate calculator, which states about 4 hours, at present difficulty. Sorry if this has been up before, but I'm really puzzled.. Title: Re: Block non-convergence soon? Post by: davout on December 26, 2010, 10:52:15 AM The nonce overflows very often, but the timestamp changes often too :), and even if it didn't the merkle root can
Title: Re: Block non-convergence soon? Post by: mimarob on December 26, 2010, 11:10:08 AM aha, so in general any given block with the nonce as the only variable is not likely to have a solution at all?
Are there some statistics on how often the non-nonce parts of the current block changes? Title: Re: Block non-convergence soon? Post by: Mike Hearn on December 26, 2010, 11:26:50 AM There is an "extraNonce" part of the block. It's where the script would be in the generation transaction, called the coinbase data. When nonce overflows extraNonce is incremented.
Title: Re: Block non-convergence soon? Post by: jgarzik on December 26, 2010, 03:37:12 PM aha, so in general any given block with the nonce as the only variable is not likely to have a solution at all? It is always possible that there is no solution for the entire range of nonce (0 - 0xffffffff). However, the timestamp and extranonce are changed every few seconds, as is merkle tree root. This helps avoid a situation where we get stuck with no solutions. |