Some General questions about mining I haven't found answers to

[mxc0bbn]

First off, I'm still pretty new to crypto-currencies, but I think I have a relative good grasp of the concept.  There are still a couple of things I still don't understand:


1.  Who is the ultimate keeper of the "golden" Bitcoin BlockChain?  That is to say, I know everyone that has a BTC wallet has a copy of the blockchain, but who keeps the master copy from which we all download when we install a new wallet?


2.  When mining you essentially download a block and have at it until you hash an acceptable solution.  At that point it can be said you "found a block" and you are given the reward of xx bitcoins.  Someone correct me if that's not correct...If it's ok then my question is this:

If you and 50 other people download block "abc123" and are all working individually to solve that block, will you know if someone else solves it first?  Will your hardware keep mining not knowing that block has been solved or do you get an update from the network saying "new block found and it's the one you're working on so stop mining that one and get another one"?

Thanks,
Mike

[Graet]

1: we all do, your client connects to someone else's client - if there was a "central repository" or "master copy" Bitcoin could not be decentralised
2: pretty much, for everyone mining to agree it is a valid block your bitcoind "broadcasts " it to the network, other miners verify it is valid, throw away old work and start "on new block"

[bcpokey]

There are rare occasions where blocks are "orphaned", in that someone finds a solution and broadcasts it, while someone else working on it finds a later solution before being "informed" of the existing solution, tries to broadcast their solution, but is rejected by the "real" blockchain, and loses credit. It's fairly rare though. Usually you'll receive an update from the network to switch to the new block.