Applications Discussion Recap

[John Taylor]

Hi all,
It's been quiet for a while, so I thought I'd see if I can summarize  
where we'd got to before the lull.  This is a slight rehash of an  
email I sent a few weeks back.

Areas where we agree:
==================
* We will concentrate initially on application to application  
messaging for a single user on a single machine
* We will have a hub/daemon process to control the messaging
* The messaging system will be kept simple: no encryption, no  
transactions, guaranteed delivery etc
* The messaging protocol will be decoupled from the semantics of the  
messages

Areas where I think we agree, but I'm not sure
===================================
* The messaging protocol will be defined independently of the details  
of any concrete implementation (this does not preclude such details  
also forming part of the specification)
* Applications are free to spawn/include an instance of the hub/ 
daemon, but should behave "nicely" (TBD) if they shut down or one is  
already running.
* We won't attempt any clever hand-over from one hub/daemon instance  
to another.
* Applications will be located dynamically (through the hub/daemon),  
rather than from a remote or local registry
* The mechanism used to bootstrap the connection to the hub/daemon  
will be simple


Areas still to be discussed/agreed
==========================
* A representative list of use cases (see follow up)
* Precisely how we bootstrap the connection to the Hub/daemon
* The messaging protocol
* Which "wire" protocol(s) to use
* Pretty much everything to do with the messages themselves
* What we should aim to achieve by the May interop

So....still a lot to do.

I've put this list up on the wiki, and I'll try to keep it current as  
the discussions progress.  If you disagree with what I think we agree  
(!), then let me know and I'll put things right.

See:
http://www.ivoa.net/twiki/bin/view/IVOA/ApplicationsMessagingStorySoFar


John