Quote from: lzsaver on October 02, 2010, 05:49:47
Can you tell more about it:
“they have to do weird things with extraNonce, which increases the size of the block header”.

Quote from: theymos on October 02, 2010, 06:11:11
When you generate, you calculate hashes of the block header. Hashing more data is slower than hashing less data, so the block header is critically of a fixed size for everyone, with one exception.

This is the point of confusion.  extraNonce is not part of the block header, it is part of the first transaction.  It does not slow down your hashing.  It does not change the size of the header.

We need to be vigilant and nip in the bud any misconception that the contents of your block slows down your hash speed.  It doesn’t.

extraNonce never needs to be very big.  We could reset it every second whenever the time changes if we wanted.  Worst case, if you didn’t want to keep track of incrementing it, extraNonce could be 4 random bytes and the chance of wasting time from collision would be negligible.

Separate machines are automatically collision proof because they have different generated public keys in the first transaction.  That also goes for each thread too.

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