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From: "Pat Rogers" <progers@acm.org>
Subject: Re: Depending on passing mechanism
Date: 1997/10/23
Message-ID: <01bcdfe0$84bd5440$560c6dce@my-pc.neosoft.com>#1/1
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References: <x2hgal3jxa.fsf@moon.inf.fu-berlin.de> <dewar.876842858@merv>
 <hbaker-1410971205270001@10.0.2.1> <EIDp0s.F4y@world.std.com>
 <hbaker-2110971616360001@10.0.2.1>
 <mheaney-ya023680002110972333400001@news.ni.net>
 <hbaker-2310970735010001@10.0.2.1>
Organization: Software Arts and Sciences
Newsgroups: comp.lang.ada
Date: 1997-10-23T00:00:00+00:00
List-Id: <comp.lang.ada>


The History of Ada, by Henry Baker.  It would be nice to see an IMHO
somewhere in these many posts...

Henry Baker <hbaker@netcom.com> wrote in article
<hbaker-2310970735010001@10.0.2.1>...

[snip of previous quote from another individual]
 
> I agree that Ada's attempts to provide accurate ranges of numbers are
> laudable.  But PL/I and Cobol offered equally (some would say more
> equally) powerful capabilities.  But the history of Ada indicates a
> deep disconnect between people like yourselves that have to deal with
> real hardware and real data formats and the academics.  The academics
> were worried about something totally different, and in fact, it first
> appeared as though Ada would not be able to properly specify exact
> hardware formats at all.  This is one case where 'real' programmers
> were able to prevail.
> 
> The academic notion of number ranges was not wrong, but it was not
> carried through.  Even a cursory glance at the 'interpretation' of
> the Ada standard shows that they missed by a mile.
> 
> For example, there was no guarantee that a variable with a particular
> range could be guaranteed to always have a value in that range!
> 
> There were no tools for Ada that would allow one to step through a
> program and verify symbolically where range constraints were met, and
> where they weren't met.  Such a tool would be invaluable in the
verification
> of a real-time embedded system.  Instead, Ada people spent all this time
> on the semantics of exceptions, which people who actually had to program
> reliable real-time embedded systems promptly turned off!
>