Re: Not intended for use in medical,

["Nick Roberts" <Nick.Roberts@dial.pipex.com>]

Matthew Heaney <mheaney@ni.net> wrote in article
<mheaney-ya023680001205972045490001@news.ni.net>...
[...]
> Do you disagree with the argument that a language is "bad" -
specifically,
> Ada - if it's difficult to implement a compiler for it?
> 
> Do you disagree with Les Hatten who said that Ada shouldn't be used,
> because it has a "large number" of interpretation requests?
> 
> Do you disagree with Tony Hoare's assessment that Ada should not be used
> for systems where high reliability is required?
> 
> Inquiring minds want to know...


Ada is a bit like the Mustang of the world of Second World War fighter
planes. This aircraft was described as the 'Rolls Royce of the air'. It was
a fabulous plane, and it represented (more or less) the apex of the
development of that particular technology. But, then, along came jet
fighters, and it was totally obsolete.

In the same way, I'm sure that no 'traditional' programming language will
ever be invented which is significantly better than Ada (or C++, or one of
the various other languages which are at a similar level), because very
soon a new generation of programming environments will become prevalent
which work in a different way. [These are languages which tend (mostly) to
be programmed directly by other programs, and only indirectly by humans. I
could go on about this at length, but this newsgroup is probably not the
right place.]

The point is, there's no reason not to use Ada (et al) because there's no
real alternative, and there never will be. In 300 years time from now, (the
base subsystems of) spaceships will still be programmed in Ada (or C++ or
whatever), because there will never have been the need to supercede the
language or the software. People still use tables and chairs which were
designed centuries ago; the designs are as good today as they were then:
good enough. However, in 10 years time, new software will mostly be created
using Super AI Intuitive Visual Java Workshop (or whatever), and actually
writing source code at all will become unusual.

Is Ada a bad language because it is complicated to implement? No: the
goodness of a language and the ease of its implementation are two totally
different things. However, a language may fail in the marketplace if it is
difficult to implement.

Should Ada not be used because its standard attracts a large number of
implementation requests? One may be wary of the quality of implementations
of the language; but this does not preclude the possibility of good
implementations. The language may have benefits to offer which weigh in its
favour.

As for Mr. Hoare's assessment of Ada. How many (real) high-reliability
systems did he write? Is he really qualified to make judgements of this
kind? If software I have written in the past fails, a number of service
personnel stand to lose their lives as a result. I would not have chosen
Ada to write this software (and I did have the choice, then) if I had felt
it would put them (and the efficacy of part our defence forces) at risk.

Nick.