Re: Open Systems closed to Ada?

[cis.ohio-state.edu!zaphod.mps.ohio-state.edu!sdd.hp.com!elroy.jpl.nasa.go]

In <723739755.28314@minster.york.ac.uk> mjl-b@minster.york.ac.uk writes:

>In article <1992Dec4.163301.1791@mksol.dseg.ti.com> mccall@mksol.dseg.ti.com (
fred j mccall 575-3539) writes:
>>In <1992Dec4.074834.24047@gvl.unisys.com> lonjers@prc.unisys.com (Jim Lonjers
) writes:
>>
>>>It may come as a surprise to many folks that yes, even when people have a
>>>choice, many choose Ada, and it is not limited to the more highly
>>>publicized cases of Boeing (777) and Motorola (the Cellular Telephone
>>>system).
>>
>>I think the question is not whether many do or not, but relatively how
>>many when compared to other choices, and what are the jobs it is
>>chosen for.

>No, I think the quesion is _why_ did they made their choices.

>My reasoning: Suppose many people may make a bad choice. Does this make the
>choice any better?

Suppose many people made their choices based on unfouced assertions
about language superiority for this or that purpose?  You're just as
lost here, and probably will here "because it's better" a lot from
everyone.  I think looking at the TASKS to be performed and the
success or failure at those tasks makes for a less biased measure, if
there is any pattern to the choices at all.

>>>[Just a few words of support for Dave Emery who seems to be under attack
>>> for his views -- I too have observed the same pro-C militant attitudes.
>>> Shall I say it?  Yes, it seems to be pretty much out of ignorance.  Most
>>> of those who are militantly in favor or against any particular thing
>>> are not all that well versed in the alternatives.
>>
>>And here we see the militant Ada attitude; if you don't agree with
>>them that Ada is superior to everything, it must be because you're
>>ignorant. 

>This is an extreme response to Jim's statement of his experience.

How so?  Let's take a look at what we've seen asserted in this thread.

1) People who favor C over Ada only know C.
2) People who favor Ada over C have a knowledge of a multitude of
languages. 
3) People who favor C over Ada do so pretty much out of ignorance, and
the C community are the American Ayatollahs of computer language.

Now then, where was my remark such an 'extreme response', except
perhaps that the 'target' was people favoring Ada instead of people
favoring C/C++?

>>> About the only thing that C has going for it is that it has a large
>>> trained base of programmers (how well trained, I do not know).  This
>>> is because most of the schools now teach C as part of the curriculum,
>>> or when a curriculum does not teach a particular language, C is
>>> encouraged.  It is also easier to write little C programs than it is to
>>> write little Ada programs.  
>>
>>The only thing?  Gee, that sort of begs the question of how it got
>>started, then, doesn't it?  I mean, why did all those schools start
>>teaching C and how did it get so popular?

>It would indeed be interesting to find out why, as this sort of question is
>the crux of why Ada is not more widespread. Again, you seem to be equating
>"popular" with "good". My favourite refutation analogue follows:

No, I'm not equating popular with good.  The assertion was made that
the only thing C has going for it is a large trained base of
programmers and that schools teach it.  Well, extrapolating back into
the past, that can't have always been the case, so C must have, or at
least had in the past, SOMETHING else going for it.  This is a
question that isn't addressed in the ex-cathedra pronouncement that
the only thing C has going for it is a large trained base of
programmers, coupled with the backhand slap about "how well trained, I
do not know".  In point of fact, this pronouncement is falsified
simply by the fact that there must have been a time in the past when C
DIDN'T have a large trained base of programmers and WASN'T taught in
school.  If that were ALL it had going for it, those things would
never have come about.

>>> It is interesting that C++ has invented an inter-language
>>> calling mechanism.  
>>
>>Why 'interesting'?  Any language that does name mangling (as C++ does)
>>is going to need an inter-language calling mechanism to tell the
>>compiler NOT to mangle certain identifiers so that the linker can find
>>them, particularly if backward compatibility and the ability to link
>>to modules of a language that does not do such mangling (C) is one of
>>the design goals.  This was hardly 'borrowed' from Ada.

>You've missed Jim's point about inter-operability of langauges. Yours is an
>implementation issue and very specific to Unix-style linkers. With a simple
>language like C, you only need a simple linker. But for more advanced
>langauges, you're going to need a more advanced linker, or more "mangling".

Well, no, I didn't miss it at all.  The implication is all through
there that C++ is borrowing this or that from Ada, as a demonstration
of Ada's ostensible superiority.  I simply pointed out that this was
neither borrowed from Ada nor particularly surprising.  

>>> Also that the C community is now re-inventing
>>> tasking (threads), but doing it differently, but not better than,
>>> Ada.  
>>
>>I wasn't aware that Ada 'invented' threads -- I don't believe that
>>putting them into C++ was borrowed from Ada, either, but rather driven
>>by the POSIX 'lightweight process' concept.

>I wasn't aware that anyone was claiming that Ada invented threads.

Read the implications of the statement I'm replying to.  "Gee, Ada had
tasking already, and now C++ is 'reinventing' it."

>Ada was one of the first languages to include a tasking model. All the
>tasking stuff was pretty new and untried back in the early 80s. The POSIX
>lightweight threads effort was driven by broadly similar goals to the Ada83
>language team, and it's no surprise that they ended up with a very similar
>model.

Actually, I understood that there was a certain amount of friction
between the Ada Working Group, who wanted Lightweight Processes to
reflect the Ada tasking model, and a number of other interests who had
other concerns that they didn't feel the Ada tasking model met
sufficiently.  Of course, this is hearsay, since I wasn't there, but I
certainly don't find it particularly incredible.

-- 
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
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Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me.