Path: news.daimi.aau.dk!sbrandt
From: sbrandt@daimi.aau.dk (S|ren Brandt)
Newsgroups: comp.lang.beta
Subject: Re: : Distributed BETA: components and remotables incompatible?
Date: 1 May 1995 13:24:59 GMT
Organization: DAIMI, Computer Science Dept. at Aarhus University
Lines: 37
Message-ID: <3o2nfb$3gb@belfort.daimi.aau.dk>
References: <3nnone$6ei@fbi-news.informatik.uni-dortmund.de>
NNTP-Posting-Host: quercus.daimi.aau.dk
Keywords: Mjolner,BETA,Distribution,component,coroutine,remotable

Thus spake warda@ls4.informatik.uni-dortmund.de (Armin M. Warda):

>The Mjolner BETA System - Distribution - Reference Manual 
>[MIA 93-25(1.1) Section 4.11 'Tracing object serializations', 
>P. 14]:

>   "[...] Most often the error message resulting is 
>    'component not handled', that is triggered when 
>    trying to pack an active object (i.e. a component)."

>Does this mean, that components (= coroutines) and 
>remotables (= remotely accessible objects) are incompatible?

The above section of the manual refers to the fact that the object
serialization (marshalling) engine used by the distribution library
cannot serialize component objects. The reason is that component
serialization involves moving execution stacks between different
processes, which is not exactly trivial. Especially not across
different hardware platforms...

As a consequence, you cannot send component objects as parameters
to remote calls.

>Which restrictions exist?

>For example, is it possible to (re-)activate a component 
>that resides in a different shell or even ensemble?

A remoteable object cannot be a component itself, but may serve as an
interface to a component object. This way it is of course possible to
activate a component that resides in a different shell.

Hope this helps.

  -- Soren

>A.