Subject: Re: De-confused...

From: [email-masked] (Tom Henderson)
Date: Tue, 27 Jul 93 10:45:43 MDT

Lyndon,

> > Would it be possible to satisfy the "well known context" idea by having a 
> > static array of named contexts available for use by a server developer?  
> > Something like this:  
> > 
> >   MPI_NAMED_USER_CONTEXT_0
> >   MPI_NAMED_USER_CONTEXT_1
> >   ...
> >   MPI_NAMED_USER_CONTEXT_63
> > 
> Looks like these just bring back the original problems that opque
> contexts were supposed to remove.  I think the idea of well-know
> contexts becomes meaningless and dissapears once they become opaque. 
> 
> Best Wishes
> Lyndon

With contexts being opaque objects, we could arrange a bit more "security".  
Each MPI_NAMED_USER_CONTEXT would have an associated flag that "disables" the 
context unless the context has been explicitly reserved by using 
MPI_CONTEXTS_RESERVE().  For example:    

    MPI_CONTEXTS_RESERVE(1, MPI_NAMED_USER_CONTEXT_0);

I'm not sure how much extra "security" this would provide...  

Personally, I'd prefer to use publish/subscribe and use a "well known" 
character string for my servers.  I'm a bit concerned that publish/subscribe 
won't make it though...  

Tom