Re: ARIANE-5 Failure (DC-X works)

[smize@Starbase.NeoSoft.COM (Samuel Mize)]

In article <dewar.834287759@schonberg>, Robert Dewar <dewar@cs.nyu.edu> wrote:
>Eugene says
>
>"vehicles have problems.  The DC-X flight control software is in Ada and
>is all computer generated.  You would not want to maintain this code by
>hand."
>
>Sounds bogus, ultimately the code is maintained by humans, we do not yet
>have robots that can write and maintain code. Sure the code may be in
>some other language than Ada and then generate Ada (if the Ada is not
>maintained, but is just used as an intermediate language, it is 
>essentially irrelevant that it is Ada). So the question is: what
>language WAS the software written in? And what is the argument that
>this code is easier to maintain than properly written Ada?

Other posts have said the code was generated with MatrixX.  I haven't
used MatrixX, but others at my company have, so I'll try to describe it.

MatrixX isn't a language.

It's a tool that uses a graphical notation, including some standard
graphical notation for math.  You can think of it as a 4GL for
scientific calculation.

Its application area is limited, but within that area, its graphic
notation is closer to what a mathematician would use, so a domain
expert can work with it and validate it more easily.

I'm sure a MatrixX marketeer would plotz at this definition, but it
lets you see why it's easier (in this case) to maintain than properly
written Ada.  The maintainers aren't programmers, and they aren't
maintaining the program.  They're maintaining their mathematical
specifications.  The tool regenerates the program to match new specs.
Nobody maintains (this part of) the program.

>I am always running into the vague notion that someone program generators
>and CASE tools eliminate programming completely. All too often what is
>really happening is that the code is being written in some poorly designed
>and poorly defined and poorly maintained language.

No argument there.  However, MatrixX seems to be a fairly solid tool
for its appropriate application areas.  I say this from outside
observation, not from personal experience.  Your mileage with it may
vary; your particular car may not even start with it.

But since Ada is a general language, there will always be tools that
are easier for specific, limited application domains.

Samuel Mize