Hi,

as I understand it, the miner goes through up to 2^32 values of the nonce field (which the fourth word in the message), calculates sha(sha(message)), and submits the proof-of-work to the pool if the last word in the hashing result equals to 0. Good.

Now the questions.
1 What other fields can we change in the message when mining, other than the nonce?
2 Where is the extraNonce located?
3 Where is the time (and can we change it as we see fit while mining, or are we required to keep it in a certain range)?

I've been reading through the protocol specs on wiki, but couldn't really figure it out.... Thanks!

-B