Re: Ada Annex E (Just curious :-)

["Marin David Condic" <marin.condic.auntie.spam@pacemicro.com>]

"Robert A Duff" <bobduff@world.std.com> wrote in message
news:wccg0gqqzvc.fsf@world.std.com...
> A major goal of Annex E is to allow the user of a compiler, or a third
> party, to provide the (low-level) communications software, *without*
> modifying the compiler.  The compiler provides marshalling/unmarshalling
> of data structures and so forth, and there's a well-defined interface to
> the communications software, so you should be able to plug in your own,
> and still get RPC.  Is there some way in which this goal is not
> achieved?
>
Well, this is, of course, going to be implementation dependent. I could
imagine a well designed compiler providing a well documented programming
interface so that the embedded developer had to build some
packages/subprograms & link with the compiler's runtime and - "then a
miracle occurs" - and you're off and running with RPC's, etc.

But you've still got potential problems because you may have different
compilers for the different processors. They may not do things quite the
same way, so you aren't necessarily going to be able to get the code from
one compiler to RPC code from the other. The situation with simple data
accesses is similar.

Please, don't get me wrong here. I think the Distributed Annex is a great
idea and goes a long way to providing solutions for a lot of problems. I'm
just observing that in a problem space where you have dissimilar computers
and non-standard communication mechanisms, it may be difficult to use Annex
E. Even something like having to build the communication interface
underneath the compiler is still a matter of mucking about with the compiler
to adapt it to your machine. This doesn't get done at no cost. Maybe you can
get there and maybe it even ends up cheaper in the long run because of
reduced complexity, but it is something that needs to be looked at carefully
depending on the environment.

I recall hearing that in Japan, it is considered rude to say that you can't
do something or that something is impossible - so they say "It would be
difficult" instead. I'm wondering if I'm saying that with the same meaning?
:-)

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
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