On 8/31/07, Simon Laws <[EMAIL PROTECTED]> wrote: > > > > On 8/31/07, Raymond Feng <[EMAIL PROTECTED]> wrote: > > > > What's the use case to have one JVM joining multiple SCA domains (even > > theoretically it's possible)? I agree with Simon that one node should > > only > > belong to one SCA domain but it seems that he also hinted that one JVM > > can > > host more than one node. > > > > Thanks, > > Raymond > > > > ----- Original Message ----- > > From: "Simon Nash" <[EMAIL PROTECTED]> > > To: < [email protected]> > > Sent: Friday, August 31, 2007 1:20 PM > > Subject: Picture on the Tuscany website SCA Java page > > > > > > > The picture on http://incubator.apache.org/tuscany/sca-java.htmldoesn't > > > look quite right to me. It seems to show a node that is split between > > > two domains. I think an SCA node is part of exactly one domain. It's > > > > > possible for more than one domain to run in a single JVM, but from an > > > architectural perspective these domains would each instantiate a > > separate > > > node within the same JVM and would not be part of the same node. > > > > > > Simon > > > > > > > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > We are maybe using the term Node to mean different things. > > For me a node provides runtime resources (1,2 or 3 below) to one ore more > domains. I used the word Node instead of runtime as we already use the term > runtime in the code (ReallySmallRuntime) and the runtime is currently owned > by the domain. > > So the resources that a node might represent are > > 1 - A part of a JVM > Scenario: some application container is making runtime resources available > to our domain applications > > 2 - A single JVM > Scenario: a stand-alone tuscany program > > 3 - A collection of JVMs > Scenario: a high performance compute cluster. We may choose to run > component instances across multiple JVMs for performance reasons but the > cluster is not visible to the topology of the domain. As far is it is > concerned the cluster is one node. > > This is distinct from the distributed domain scenario we have implemented > to date where multiple nodes are used to enable the distribution of the > components in the domain. > > 4. Raymond has raised something else in another thread about "partitions". > I will let Raymond explain that. > > We also individually consider that a Node might be associated with one > domain or many domains. > > The key point is what we think a node is. From Simon's comment "these > domains would each instantiate a separate node within the same JVM". To make > this work there must be a mechanism within the JVM that allows domains to be > associated with the JVM. For me this is the node but I'm not hooked on this > particular term. > > As for scenarios of multiple domains in a JVM. I imagine a JVM supporting > multiple domains in the same way that an application server can support > multiple unrelated applications. This may sound a bit marginal for nodes > with resources of types 1 > > > Simon > > > > > > > > Oops, pressed send too soon. I was going to finish with...
This may sound a bit marginal for nodes with resources of type 1, I thought business as usual for type 2 and particuarly important for nodes with resources of type 3. This is why I was using the word node rather than JVM directly. Simon
