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Adding to the SDL wagon: I have had to implement the Q.SIG standard
and with a little thought it is possible to get Erlang code that is
almost 1:1 with the SDL diagrams - there is a little example in the
EUC 2010 presentation by Raghav Karol and me where we have one
function call for each box in the SDL diagrams. That makes it very
easy to debug the code in the rare case that one has done something
wrong ;-) <br>
<br>
But for creation of new software where there is no SDL specification
of the protocols there is no real benefits of creating SDL before
coding. For that I think that Object Process Methodology (used
lightly) and Message Sequence Charts are better ways of structuring
your high level thoughts.<br>
<br>
Cheers,<br>
Torben<br>
<br>
On 7/12/11 18:24 , Ulf Wiger wrote:
<blockquote
cite="mid:01F34AC4-97BF-43C8-9D12-CA47B791DF94@feuerlabs.com"
type="cite"><br>
<div>
<div>On 7 Dec 2011, at 18:04, Max Lapshin wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite"><span class="Apple-style-span"
style="border-collapse: separate; font-family: Helvetica;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: 2; text-align: -webkit-auto; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-border-horizontal-spacing: 0px;
-webkit-border-vertical-spacing: 0px;
-webkit-text-decorations-in-effect: none;
-webkit-text-size-adjust: auto; -webkit-text-stroke-width:
0px; font-size: medium; ">Ulf told something about SDL, but
I really don't know what is SDL.<br>
</span></blockquote>
</div>
<br>
<div>SDL = Specification and Description Language, is a ITU-T
standard language for describing systems of communicating state
machines. This was used much in Telecoms, and in real-time
systems design, often together with Message Sequence Charts
(MSC), to produce high-level systems architecture diagrams.</div>
<div><br>
</div>
<div>SDL also extends down into programming with SDL/PR, but we
can ignore that. ASN.1 - a loosely related data description
layer - is however still quite relevant.</div>
<div><br>
</div>
<div>In the great UML:ification, SDL was absorbed into UML. Before
that, it became more and more object-oriented. Still, the
earlier versions are actually fairly decent for describing
erlang-based systems. In fact, it was once shown that a system
described in SDL could be mapped 1:1 over to Erlang. This has
not been done much, since it was also easy to demonstrate that
the same system could be more easily described in Erlang in the
first place (although such a description would lose many of the
qualities of a good system architecture description).</div>
<div><br>
</div>
<div>Here is a tutorial of sdl88. The link jumps directly into
something that ought to look familiar:</div>
<div><br>
</div>
<div><a moz-do-not-send="true"
href="http://www.sdl-forum.org/sdl88tutorial/4.ProcessCommunication/4.1_Signal_input_queue.htm">http://www.sdl-forum.org/sdl88tutorial/4.ProcessCommunication/4.1_Signal_input_queue.htm</a></div>
<div><br>
</div>
<div>Here's another overview:</div>
<div><a moz-do-not-send="true"
href="http://www.cs.nthu.edu.tw/%7Etanghome/SDTDoc/introsdl.html">http://www.cs.nthu.edu.tw/~tanghome/SDTDoc/introsdl.html</a></div>
<div><br>
</div>
<div>BR,</div>
<div>Ulf W</div>
<br>
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<br>
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</blockquote>
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