I think I've reached a reasonable (-ish) understanding of blockchain and bitcoin as it works just below the surface, but I still don't get that surface view. So, from the umpteen videos I've watched, I can see that there are at least three roles -- i.e. kinds of people/companies -- involved:
A. End Users -- people who just want to use bitcoin. For example, I might have BTC in a bitcoin wallet on my smartphone and I use it to buy a pizza via Lightning. And then transaction ends up correctly residing in the blockchain
B. Miners -- people who bundle up a bunch (two to three thousand I believe?) of End User transactions like mine, do the POW "stuff", and package the whole lot into a new block to be offered for acceptance into the blockchain
C. Chain Maintainers - I made that name up 'cos I'm not sure what to call them. But they are the people/agents responsible for accepting the newly mined blocks from the various Miners and deciding if/when to fork, which forked chain is longest, when to discard a branch deemed to be dead, and so on. In other words, they are the ones who make decisions on which blocks are accepted, based on the Proofs of Work done by the various Miners.
So my questions are:
- How, and in what form, do my End User transactions between me and my pizza purchase say get out into the world and eventually reach the Miners? Do they go directly -- but that would mean gazillions of pizza purchases etc flying about? Or do they all go to some kind of aggregator -- one of the "Chain Maintainers" perhaps -- who bundles them up into batches and sends those bundles out to the Miners?
- Once my transaction gets to the Miners, and they have then packaged it and others together into a POW'ed block ready to be offered to the "Chain Maintainers" for acceptance, exactly what does it broadcast? Is it just the new block itself? Or is it the entire chain with the new block appended? BUT SPECIFICALLY:
- How does the Proof of Work information itself get from the Miners to the Chain Maintainers? I don't mean the hash itself -- I mean the fact that Miner A expended 4 GigaOodles of Work to produce its version, whereas Miner B expended 800 TeraOddles of Work to produce its version? I presume it's in the newly mined block itself, but where and in what form? AND FINALLY:
- Where, exactly, does the famed Blockchain actually reside? Or rather, who maintain copies? Since it's currently several hundred GB in size and growing, I know I don't have a copy in the wallet in my phone, so who does? Is it just the various people/organizations in the "Chain Maintainers" group; every single Miner as well; someone else; who?