Re: Ariane 5 - not an exception?

[kbradley@us.oracle.com (Kirk Bradley)]

Why do you say that PL/I has no signalling facility. What do you
call ON units? how do they get triggered?  I'd say it for sure
has signalling 

In article <32106B34.57DB@lmtas.lmco.com>, Ken Garlington
<garlingtonke@lmtas.lmco.com> wrote:

> ++ robin wrote:
> > 
> >         >  2) PL/I
> > 
> >         >     a) There is no PL/I compiler for the 1750A
> > 
> > ---Not an obstacle.  How was an Ada compiler written for it?
> 
> I believe an existing one was purchased. I don't believe an Ada
> compiler was written specifically for the Ariane SRI, as apparently
> you are suggesting be done for PL/I. How would your argument about
> mature PL/I compliers stand up in the face of a requirement to 
> develop a brand-new compiler for a new target?
> 
> > 
> >         >     b) Ada is far more suitable for safety-sensitive
software than Pl/I
> > 
> > ---Nonsense.  PL/I has a long (30 years) record in
> > excellent real-time facilities, and with people with
> > experience in error-recovery and fail-soft in routine
> > commercial applications as well as real-time programming.
> 
> It must be the lag in these newsgroups. I've posted more than one
> request in comp.lang.pl1 for some examples of PL/I's use in safety-critical
> real-time flight software, and narya a taker yet. I look forward to
> some examples...
> 
> Perhaps those people are too busy building such software to read
> the Internet?
> 
> >         >     c) This failure was not a language issue.
> > 
> > ---Isn't it?  One of the arguments put forward was that
> > an Ada condition couldn't be raised and leave a trace,
> > and that it would be argued that there was no guarantee
> > whether a piece of code was executed.
> 
> That argument could be put forth, but of course it would be false.
> We routinely trace Ada 83 exceptions in our debugging environments.
> Ada 95 also adds a standardized capability to annotate exceptions with
> user-defined information.
> 
> >    In PL/I, a SIGNAL statement (which can be used for
> > program checkout) leaves a printed record that it was
> > executed.  It gives a message that the condition was
> > raised, and comes with line numbers, etc.  There is
> > absolutely no doubt that the statement did not execute!
> 
> There is no SIGNAL statement in PL/I. In fact, PL/I has no
> exception handling capabilities. (I figure, since ++robin can
> continue to ignore the capabilities of Ada, why shouldn't we
> ignore his claims as to the capabilities of PL/I)?
> 
> As a side issue: Could someone post the printer port address for the
> Ariane SRI? Most of our IRSs don't have a printer attachment.
> Must be something those experienced PL/I programmers demand be
> added to the hardware... :)
> 
> > 
> >         > But
> >         >     stupid management is something no programming language
can change.
> >         >     Given other engineering constraints on this project, Ada
is really
> >         >     the only reasonable language to choose.
> > 
> > ---Scarcely convincing, in view of the failure.
> 
> Again, I would be more convinced of _your_ arguments if you would post some
> of the flight software items you've developed in PL/I. For some reason,
> this request keeps getting lost in the newsgroup. Until then, I think I'll
> just enjoy the speculation...
> 
> -- 
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