Re: Distributed system portability

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

That might or might not work, depending on what your requirements are for
the external representation of the data. If you define the whole thing
yourself, then whatever way you output the data is the way you input the
data & defining the operations for the primitive types is (probably) good
enough. However, you *could* be in trouble if there are requirements to
traverse byte boundaries or find things in the middle of words or otherwise
have to do something "wierd". You might also discover that this whole thing
can get rather painful if you have lots of user defined primitive types.

I've seen messages defined in systems that aren't easily dealt with via the
Stream attributes. If you're limiting yourself to a subset of the possible
representations of messages in a stream, you can get by, but if you have to
deal with all of the possibilities it gets complicated.

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


<tmoran@acm.org> wrote in message
news:QAC97.18171$Kd7.10872006@news1.rdc1.sfba.home.com...
> >you have to do *all* this (including implementing all the stream
attributes for
> >*all* types that will ever be used with the stream, excepting perhaps
some
> >composite types). With that much work involved, the streams aren't really
> >providing you much except the supposedly nice syntax.
>   (I haven't tried this but ...) I think you just have to implement the
> base types, and you need do it only once.  So if you are going to be
> doing a lot of systems where data goes between a machine of type A and
> another B with different architecture or compiler, you can implement
> integer'read etc just once, and all your different programs can use it
> for integers ... composite types.  Isn't that in fact done for the
> Gnat distributed systems implementation?