Terms

[Tony Linde]

Hi Ray,

> > I've left out 'resource' deliberately - it is a somewhat 
> loaded term. 
> > And I've tried to keep to the higher level entities at this stage.
> 
> The definition provided by the RM is intended to clarify this 
> and allow us to use the term without fear.  

Sorry, I wasn't clear. I wasn't leaving it out because it hadn't been
defined but because, as you say, it is deliberately broad. It is loaded in
the sense that we tend to identify a resource as something with a separate
record in the registry and I wanted to avoid that discussion at this stage
(says he, doing just that with the 'interface' discussion!). I'll put it
back now, anyway.

When we come on to terms relating to the provision of data and services, I
like the idea of replacing Data Centre with Provider: the latter is both
more constrained and less loaded than the former.

I want to introduce the term that Clive mentioned, Site, and would like to
use it to provide some locational information for a Provider. But I'm not
sure if we want a provider to be constrained to one site or a site to one
provider. I'll model a more flexible, many-to-many, relationship for now. We
do need some sort of location information for the case where we want to
determine which service of many fronting the same resource (data collection
or application) is nearest to some other resource. And no, I've no idea how
to define 'nearest' either :)

> -----Original Message-----
> From: owner-registry at eso.org [mailto:owner-registry at eso.org] 
> On Behalf Of Ray Plante
> Sent: 14 December 2004 07:35
> To: registry at ivoa.net
> Subject: Re: Terms
> 
> Tony et al,
> 
> On Thu, 9 Dec 2004, Tony Linde wrote:
> > One of the problems we have is that we're all using different terms 
> > for the same things (or vice versa). Can someone (Roy?) provide us 
> > with a reasonable glossary of entities that we need to look 
> at and quickie definitions.
> 
> Please recall that the RM document defines a number of terms 
> that are relevant to this discussion.  
> 
> > I've left out 'resource' deliberately - it is a somewhat 
> loaded term. 
> > And I've tried to keep to the higher level entities at this stage.
> 
> The definition provided by the RM is intended to clarify this 
> and allow us to use the term without fear.  
> 
>    "A resource is a general term referring to a VO element 
> that can be 
>     described in terms of who curates or maintains it and 
> which can be 
>     given a name and a unique identifier.  Just about 
> anything can be a 
>     resource: it can be an abstract idea, such as sky coverage or an 
>     instrumental setup, or it can be fairly concrete, like an 
> organization 
>     or a data collection.  This definition is consistent with 
> its use in 
>     the general Web community as anything that has an identityâ
>     (Berners-Lee 1998, IETF RFC2396).  We expand on this 
> definition by 
>     saying that it is also describable."
> 
> The definition is deliberately broad ("Just about anything can be a
> resource") allowing us wide latitude for how we populate our 
> registries (e.g. coarse-grained vs. fine-grained).  The RM 
> document further refines the definition of a resource by 
> identifying the core metadata that can/must be included to 
> describe a resource.  
> 
> To further refine what is and isn't a resource is to impose 
> one's own additional constraints on how one perceives the VO. 
>  That is okay, but the RM standard implies that those 
> constraints need not be universally accepted.  More to the 
> point, you should not expect others be aware what additional 
> meaning you have imposed unless you explicitly say so.
> 
> As for the other terms, consider:
> 
> >  data centre (or center)
> 
> RM does not define this term; instead it talks of organizations and
> providers:
> 
>    organization:  a "specific type of resource that brings 
> people together 
>      to pursue participation in VO applications."
>    provider:  "an organization that makes data and/or 
> services available 
>      to users over the network."
> 
> Here's an other one that's important:
> 
>    Publisher:  "An entity responsible for making the resource 
> available"
> 
> I think it is fair to say that "data center" unnecessarily 
> implies more than these other terms from the RM.  
> 
> >  service
> 
> >From the RM:
>    "any VO resource that can be invoked by the user to 
> perform some action 
>     on their behalf."
> 
> >  interface
> 
> The RM does not define this directly; however, but the 
> implied definition based on the definition of "Inteface 
> metadata" is that an interface is the mechanism for accessing 
> a service--namely, "the inputs and the outputs".  
> A tighter definition would be better.  
> 
> Definitions for some others are included in the VOResource 
> metadata schemas (and thus are less definitive).
> 
> >  data collection
> 
> from VODataService-v0.5.xsd: 
>      "A logical grouping of data which, in general, is 
> composed of one 
>       or more accessible datasets."
> 
> >  dataset (which I think is just my term for data collection)
> 
> from VODataService-v0.5.xsd, in an annotation to the definition of
> DataCollection:
>      "A dataset is a collection of digitally-encoded data ... that 
>       is normally accessible as a single unit, e.g. a file."
> 
> cheers,
> Ray
>