Re: Ada noob here! Is Ada widely used?
- From: "Dmitry A. Kazakov" <mailbox@xxxxxxxxxxxxxxxxx>
- Date: Mon, 7 Jun 2010 09:48:43 +0200
On Sun, 6 Jun 2010 19:27:48 +0000 (UTC), tmoran@xxxxxxx wrote:
The problem is that to apply this theory to software you need maybe,The number of bugs in a certain piece of software is analogous to the
imaginary space of elementary outcomes (independent, complete etc). I don't
see any of that in the software. It is a fundamental issue.
number of unexploded WWII bombs buried in Berlin.
No. Both are realizations of some process. The latter was to some extent
random, the former was not. If you drop bombs from the same spot they will
distribute themselves in some area. If you rewrite a line of code, you
introduce the same bug or no bug each time. The way how the source code
line N receives a bug M is not random. Lines are not equivalent in their
affinity to bugs. Bugs are not necessarily located in a single line. Bugs
are not necessary located in adjacent lines. Bugs are not same, and so on
and so forth.
There are a certain,
unknown, number, and next Wednesday none, or at least one, will be
discovered. But the probability of discovering a bug, or a bomb, is a
number which can be guesstimated.
OK, that is yet another process. It only makes things more complicated. The
way bombs are discovered could be considered stochastic, however I am not
very sure about it. As for bugs, it is certainly not stochastic. But in any
case the discovery process tells nothing about the software itself. You
need some theory/model in order to be able to say that if the bug discovery
rate was Rn-3, Rn-2, Rn-1, Rn, then it is to expect the next rate
Rn=f(Rn-3, Rn-2, Rn-1, Rn). I don't see any such theory. And it seems to me
that it cannot be mathematical statistics, at least prior to a
probabilistic model of bugs (not their discovery process).
And the size of that probability
informs our decision about whether to launch the rocket that depends on
that software, or whether to disband the bomb squad. In the real world
you can't throw up your hands and say "I don't know the probability"
because someone will ask "OK, should we launch/disband or not?" and you
need to give an answer.
Yes, and the answer is as always: 4.12... (:-))
Dmitry A. Kazakov
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