[ogsa-wg] [OGSA-D-WG] Definition of "data service"

[Donal K. Fellows]

guru prasad wrote:
> This brings me to this question: What is the difference between and data 
> source and a data resource?

A data source is an origin endpoint for a data transfer, and is
typically positioned on a data resource. A data resource is some
structured information (==data) that can be used by an activity,
monitored for changes, lifetime-managed, etc. (==resource); i.e. a data
resource is data that is a resource. Obvious really. :-)

> Is former just the container for data and latter is responsible for 
> managing one or more data sources?

Now you're getting mixed up between the service instances that implement
the concept space and the concepts themselves. Both "data source" and
"data resource" are concepts, and they map respectively to things like a
service instance that can stream the results of a database query or a
file. It might be that the two things are implemented in the same
component, but that's not required. Also, a single data resource may
have many different sources associated with it (corresponding to views
of the data, transfer methods, etc.)

If it helps, remember that I regard the act of data transfer as an activity.

Donal.