[jdev] Semantic question

[Goffi]

G'day,

for years I have used decentralised, distributed, and federated with, in 
my head, the following meaning:

	- decentralised: the ability to have several servers communicating 
together, the servers can be under the same domain (example.net can have 
several servers)

	- distributed: 1 server = 1 user, no intermediate (not even DNS, so 
XMPP is not distributed according to this definition, but something like 
retroshare is)

	- federated: the ability from servers of different domains (example.net 
and capulet.lit) to talk together, in both directions.

But after a talk I realise that the definitions accepted is not the same 
everywhere, e.g. Diaspora people talk about federation for what I call 
decentralisation. Actualy it's a bit tricky, because if one entity has 
1000 servers but everybody is using the same domain, the data are 
centralised in the hands of the same entity.

So, what meaning do you put behind these words ? Are decentralisation 
and federation more or less synonyms ?

Sorry to put this on jdev@, I was not sure of which mailing list to use :)


Goffi