Re: Interested in Formal Methods

[a hafiz]

--- Patrick Strasser <pstrasser@gmx.net> wrote:
> a hafiz wrote:
> > i share your interest in Formal Methods and especially in applying it to
> > HURD.  I have heard of VDM and B but not actually read about them let
> > alone use them. But i did do  some Z while in Uni. and although it was
> 
> We work with NewJersey-SML and we expand it to SadoMasoLanguage, and...
> half a year later... I like it. I think this first antipathy comes from
> the fact that nearly everyone learning a fromal language has used
> imperative languages like C before. You have to change your way of
> "thinking" code.
basically, formal method is kind of like programming, that's why it
CAN be fun, but of course it's completey different and it's this
"paradigm shift" that makes it hard for most people (including myself).
Anyone ever tried functional programming would understand what i mean.
 
> > Jason More, had a valid point about the whole thing. Formal Method can
be
> > very hard, and the amount of effort expended to apply it to HURD may not
> > be worth the small gain. it might still be interesting and fun though!
> 
> How can you tell? The Hurd gives us the oportunity to change a small
> part of the system and test it in "real life" in a working context. Work
> has to start in small steps. What could be a starting point? Some
> translator? Some additional frome the Task list (ps)?
> Second, a foraml language is more secure due to more abstraction.
True, i cannot tell for certain the gain is not worth the effort. But most
people feel formal method is hard and is not worth the effort. They may have
a point. But if you're a good 'Zed hacker' as oppose to a C hacker than it
may not be that hard and you will make better systems. This goes back to
my "paradigm shift" problem and your different way of "thinking code".
maybe one way to solve this problem, instead of teaching kids java, basic or
c, we should teach them VDM,Zed, etc. assuming they could understand it,
then they'll have a "paradigm shift" problem of programming C! :))

My personal experience is that formal methods is hard at first. and for
a first timer, they may just give up. I myself failed many times, but i kept
at it until i got the gist of it. It's been many years since i did any
decent
Zed, i could read a zed spec but probably won't understand much. I'll have
to
start all over again...

  
> > finally, my personal opinion on formal methods is that, it is not so
> > much the method or notation, but it is what the method or notation
> forces
> > you to do. What formal methods does is force you to think about your
> design
> > a bit more thoroughly and it guides you to do it correctly. when you
> just
> > draw some design base on some simple specs you tend to just do a quick
> > sketch and straight away jump to the coding. with formal methods, you
> are
> > more likely to expand your original idea, and explore the problem a
> little
> > more.
> 
> I.e. work is the same, but with formal languages you don't need to hunt
> bugs for nights...
exactly, because formal methods can help you avoid design flaws which leads
to program bugs.

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