Question: Is there a centralized double-spend database as in the documentation? Or am I misunderstanding this?
Nothing wrong with a centralized database, I'm just trying to understand the nature of the contribution here.
Double spends are prevented by a public database that contains sufficient information to prevent them. We call it the "ledger" and it is somewhat analogous to the Bitcoin block chain.
Since you didn't really answer the question.
Is there a central server or servers? If so, who controls these servers? How is the database updated? Through the central server or servers?
Again, there is nothing wrong with a central server or servers. But there is something wrong with doublespeak.
The public database his talking about is decentralized. In that sense the ledger is analogous the the proof of work chain. I would just call it the ledger chain to simplify things, but I'm not participating, so anyone correct me if I'm wrong.
I guess there will be centralized seed servers or something and a centralized web providing some services, but since the protocol is going to be free software, anyone can provide the same services.
So the answer to your question is that: it will be a p2p protocol. Nice, don't you think?
Yes. I don't have any problem with centralized at all. I don't have a problem with Ripple either (though I am skeptical that it will find users). I just want things to be straightforward and open rather than spun.
Presumably there is a central authenticating server. And then if anyone can provide server. It probably means anyone who is authorized by the central server.
It might also mean that anyone can clone the program and run their own centralized authenticating server which forks from the main program and relies on the same user database. This is better than nothing.
All of the above is true of SolidCoin too. There was nothing wrong with SolidCoin's design in theory. However, it was run by a nutjob who hid things from people and constantly rewrote the rules. Anyone could have forked SolidCoin and prevented him from controlling everything. But they didn't. Instead they just let SolidCoin happen.
If you want to avoid a SolidCoin-like user experience, it would be best to put the all the information on the table instead of hide things.