Resources = services!^H? (or services = resources)

[Doug Mink]

Roy Williams wrote:
> 
> > - What is 'DataCollection' and why would one want to list it if it is
> > not the service which gives access to the data?
> 
> A major data collection (eg 2MASS) may have many services that suck from it.
> 
> A service may be able to talk to many data collections (eg a mosaicking
> service).
> 
> It's a many to many relation.

It is probable that a mosaicking service, at least in a general case, would
be utilizing other services to access the data.  Any remote access of data
by a service is in some way using a second service.  One overlooked service
which every resource should provide is one which returns information about
itself, and services should do this as well.

Data as an entity will not be encountered except through a service, though
it needs to be characterized.  We should think hard about the real differences
between data and services which transfer, filter, or manipulate that data.
It is useful to know as much as possible about a data resource, more than
might be provided by any of the services which return pieces of the resource.

Services themselves are also data to metaservices which evaluate and list
them, for example, registry services.

-Doug Mink