Subject: Re: SDL-News: Fwd: [SDLTF-Members] SDL IS IN DANGER
From: Susanne Graf (Susanne.Graf#imag.fr)
Date: Thu Dec 18 2003 - 19:11:42 GMT
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-----From Susanne Graf <Susanne.Graf#imag.fr> to sdlnews -----
Dear William,
Laurent is right, one should be careful before throughing the save construct
away. As I already explained in an earlier mail. SAVE is very different from the
use of priorities. You cannot replace the SAVE construct by priorities otherwise
than in a very odd manner.
SAVE construct can be used for bad reasons:
1. first a bad one: if there are two signals a process waiting for, which may
arrive in any order. One sees then often specifications which, in order to avoid
the explicit interleavings use SAVE in order to force the consumption in a
particular order.
Duplication of programm text is not desirable, but here paralleising the
independent activities would be the nicer solution.
2. now, if there exists constraints on the order in which a process can execute
certain activities, for example A2 should never be executed before an A1 has
been done, and the processes triggering these activities are not necessarily
symchronized or don't even know about these order constraints, then there exist
2 solutions:
a) through requests which cannot be served away
b) but honsestly, this is not always a solution. Another solution is to store
the information that the request is there and do it when a state allowing this
activity is reached. Obviously you can now introduce a new variable saving the
request and it's parameters (may be even several of them), but the simplest
solution is to maintain the signal in the signal queue.
regards,
Susanne
William H. Skelton wrote:
> Become an SDL Forum Society member
> <http://www.sdl-forum.org/Society/members.htm>
> The originator of this message is responsible for its content.
> -----From "William H. Skelton" <W.Skelton#SOLINET.com> to sdlnews -----
>
> Dear Doldi,
>
> We are having a discussion based on technical justification; there is no
> need for this reaction...
>
> I am genuinely interested in your comments, and I request you to respect
> what we are trying to achieve, namely a simple, useful version of SDL;
> to increase the awareness and acceptance of the language, from having 50
> participants at the bi-annual SDL conference, when the regional Java
> forum had 750 at the same time and location!
>
> You talk about trying to defend SDL, but our activities are a serious
> attempt to take it forwards, from a position that has a monopoly tool
> supplier, who apparently has little interest in the SDL Forum and a
> specification that no-one seems to be interested in fully supporting
> (SDL-2000).
>
> No-one doubts your credentials, but I'm afraid we expect you to address
> the issues at stake and not expect us to accept something as
> 'untouchable', just because it comes from your email address. :-)
>
> Why not roll up your sleeves, join in the discussion and let us all
> benefit from your experience?
>
> William
>
>> X-Sender: doldi.laurent#pop.wanadoo.fr
>> X-Mailer: QUALCOMM Windows Eudora Version 6.0.0.22
>> Date: Thu, 18 Dec 2003 15:35:39 +0100
>> To: members#sdl-task-force.org
>> From: doldi.laurent#tmso-systems.com
>> Subject: [SDLTF-Members] SDL IS IN DANGER
>> Cc: sdlnews#sdl-forum.org, damyot#site.uottawa.ca
>> Sender: members-owner#sdl-task-force.org
>> Reply-To: members#sdl-task-force.org
>>
>> THANK YOU FOR THE 'imaginary case'. I HAVE BEEN WORKING WITH SDL AND
>> OTHER LANGUAGES SINCE 1982, ON REAL APPLICATIONS THAT ARE NOW
>> FLYING OR RUNNING, SUCH AS THE AIRBUS A310, A320, UMTS OR GPRS
>> SYSTEMS, SATELLITE COM. SYSTEMS ETC.
>>
>> PLEASE REMOVE ME FROM THE SAM04 PROGRAM COMMITEE.
>>
>> To sdl news: WHY ONLY 3 OR 4 PERSONS REACT TO THIS ATTEMPT TO
>> DESTROY SDL?! COME ON SDL FORUM, DEFEND SDL!
>>
>> Laurent Doldi.
>>
>> At 13:21 18/12/2003, you wrote:
>>
>>> Dear Doldi,
>>>
>>> Thank you for this comment.
>>>
>>> My first impression is that this is not a real requirement, but an
>>> imaginary case taken from what is possible with save.
>>>
>>> If there is a real requirement to implement this, and I have my
>>> doubts even then that this is something we should encourgae, it
>>> probably falls into the ordering problem that Qing has been looking
>>> at, and for which there is a proposal of a clean mechanism that
>>> limits the scope of this ordering.
>>>
>>> What do you think?
>>>
>>> William
>>>
>>>> X-Sender: doldi.laurent#pop.wanadoo.fr
>>>> X-Mailer: QUALCOMM Windows Eudora Version 6.0.0.22
>>>> Date: Thu, 18 Dec 2003 12:41:03 +0100
>>>> To: members#sdl-task-force.org
>>>> From: doldi.laurent#tmso-systems.com
>>>> Subject: [SDLTF-Members] Doldi thinking we want to buffer signals
>>>> Sender: members-owner#sdl-task-force.org
>>>> Reply-To: members#sdl-task-force.org
>>>>
>>>> Dear Task Force,
>>>>
>>>> If you do not buffer the signal and remove SAVE from the subset, how
>>>> do you
>>>> write the following:
>>>>
>>>> A process (instance) P has signals S1 and S2 in its queue (S1 being
>>>> first).
>>>> In state ST1, P must input S2, and signal S1 must be processed later
>>>> (in
>>>> a state ST2):
>>>>
>>>> DCL
>>>> x x_t,
>>>> y y_t;
>>>>
>>>> STATE ST1;
>>>> INPUT S2(y); etc. ; NEXSTATE ST2;
>>>> SAVE S1;
>>>>
>>>> STATE ST2;
>>>> INPUT S1(x); etc.
>>>>
>>>> What is the equivalent without using SAVE ?
>>>>
>>>> Regards,
>>>> Laurent.
>>>>
>>>> At 23:30 17/12/2003, you wrote:
>>>>
>>>>> In some case there was simply a misunderstanding, form example
>>>>> Doldi thinking we want to buffer signals, when actually we were
>>>>> talking about the parameters carried by a signal (a big difference
>>>>> between a system feature and an application feature).
>>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>> William H. Skelton, Engineering Dept.
>>> SOLINET GmbH Solutions for Innovative Networks
>>> Mittlerer Pfad 26, 70499 Stuttgart, Germany
>>> Tel +49 711 1398 1377, Fax +49 711 866 1240
>>> Mobile +49 171 247 6688
>>> W.Skelton#SOLINET.com, www.SOLINET.com
>>
>>
>> Laurent DOLDI
>> TransMeth Sud-Ouest
>> 27, av. Segoffin 31400 TOULOUSE FRANCE
>> Tel.: +33 5 61 25 59 54 Fax: +33 5 61 25 82 17
>> Mobile: +33 6 80 26 62 31
>
>
>
> ------------------------------------------------------------------------
> William H. Skelton, Engineering Dept.
> SOLINET GmbH Solutions for Innovative Networks
> Mittlerer Pfad 26, 70499 Stuttgart, Germany
> Tel +49 711 1398 1377, Fax +49 711 866 1240
> Mobile +49 171 247 6688
> W.Skelton#SOLINET.com, www.SOLINET.com
>
>
> --End text from "William H. Skelton" <W.Skelton#SOLINET.com> to sdlnews ---
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-- ------------------------------------------------------------------------ Susanne Graf | tel : (+33) (0)4 56 52 03 52 VERIMAG | fax : (+33) (0)4 56 52 03 44 2, avenue de Vignate | http://www-verimag.imag.fr/~graf/ F - 38610 Gieres | e-mail: Susanne.Graf#imag.fr --------------------------------------------------------------------------End text from Susanne Graf <Susanne.Graf#imag.fr> to sdlnews --- For extra SDL Forum Society benefits join at <http://www.sdl-forum.org/Society/members.htm>
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