Re: Improving Ada's image - Was: 7E7 Flight Controls Electronics

["Richard Riehle" <adaworks@earthlink.net>]

"David Starner" <dvdeug@email.ro> wrote in message
news:pan.2004.06.15.11.40.09.413904@email.ro...
> It's actually quite easy to write a secure, reliable OS in C. It looks
> something like this:
>
> main () {
> for (;;) {}
> }
>
> It's making a _usable_ secure, reliable OS that's hard, and most of that
> is independent of programming language.

How does one define what is meant by an Operating System?   I would include
the many Run-time environments that an Ada program includes when it is
linked.   In that case, there have been lots of functional, dependable
operating
systems.   There are other small real-time embedded operating systems, many
commercially available, and we use them with minimal frustration.  Most of
them
are written in C or Assembler.   The Ada RTE's are frequently written in
Ada.

As you know, when it comes to software, when we expect more features we
get more unexpected features.   This has always been true, and will continue
to
be true for a long time.

So, the simple OS you propose, provides little and we expect little.

Programming language can matter.  An OS written in Assembler will have none
of the
built-in checking that we get from a slightly higher level language such as
C. An
OS written in C++ has the potential for more compiler checking than one
written
in C.   The same OS written in Modula-2 or Ada can benefit from the compile-
time checking inherent those languages.     Still, none of the languages can
ensure
that the designer has avoided contradictory features,  has overlooked some
important variable setting in a declaration, or gotten the algorithms
exactly right
at every place in the program.

That being said, for any large program, where I have to understand what I am
doing,
and need to understand what my co-workers are doing, my preference is still
Ada.
For me, and I stress the "for me," it continues to be more readable and
easier to
understand what I am doing that programming in C++.   For me, Ada code is
far
more straightforward, less filled with extraneous doo-dads, and more
comprehensible
than the alternatives.   The more I am required to use C++, the more annoyed
I get
with what seems like a lot of extra stuff I should not have to need to get
my work
done.   But each of us will see this differently.

Richard Riehle