From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD,
	FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: 103376,edc919e674cd2d45
X-Google-Attributes: gid103376,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII
Path: 
 g2news2.google.com!postnews.google.com!b16g2000yqb.googlegroups.com!not-for-mail
From: Matteo Bordin <matteo.bordin@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Reactive Systems in Ada?
Date: Tue, 7 Apr 2009 05:04:32 -0700 (PDT)
Organization: http://groups.google.com
Message-ID: 
 <9c24a2b0-5be7-4c0f-bbac-8a94bb694bbd@b16g2000yqb.googlegroups.com>
References: <y5ECl.5072$Lr6.3721@flpi143.ffdc.sbc.com>
NNTP-Posting-Host: 212.99.106.126
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-Trace: posting.google.com 1239105872 26560 127.0.0.1 (7 Apr 2009 12:04:32
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Tue, 7 Apr 2009 12:04:32 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: b16g2000yqb.googlegroups.com; posting-host=212.99.106.126;
	posting-account=0fK-ZgoAAACswzEJSZ3LA9AZ4FnRU7mX
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.0.8)
	Gecko/2009032609 Firefox/3.0.8,gzip(gfe),gzip(gfe)
Xref: g2news2.google.com comp.lang.ada:5426
Date: 2009-04-07T05:04:32-07:00
List-Id: <comp.lang.ada>

On Apr 7, 10:25=A0am, Dimonax <dimo...@nospam.net> wrote:
> I've been experimenting with the Ravenscar profile and the various
> tasking facilities available in Ada.
>
> I'm curious, has anyone written any Reactive Systems of any sort using
> the Concurrency features in Ada?
>
> How does it compare to Reactive Languages such as Esterel, or Lustre,
> etc...?

Both Esterel and Lustre are domain-specific, formal modeling
technologies and thus have a completely different scope/goal than a
general-purpose programming language such as Ada. From a computational
model point-of-view, they employ the synchronous execution model and,
if they target source code, they generate purely sequential code (no
threading). Ada on the other side employs the asynchronous/parallel
model. The main advantage of asynchronous model is that it can easily
scale to multi-core (or multi-processors) systems and is easier to
compile. However, synchronous systems are usually much simpler to
analyse for their timing behaviour, information/data flow and to prove
properties on the system state.

It is possible to imagine a concurrent system whose concurrency/
synchronization architecture is implemented in Ada (possibly using
Ravenscar) and executing in (pseudo)parallelism a set of SCADE blocks.
Take a look at "A verifiable architecture for multi-task, multi-rate
synchronous software" (http://www.esterel-technologies.com/technology/
WhitePapers/).


>
> My curiosity is piqued.
>
> Dimonax