From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.2 required=5.0 tests=BAYES_00,PLING_QUERY, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: a07f3367d7,b6d862eabdeb1fc4 X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news3.google.com!feeder1.cambriumusenet.nl!feed.tweaknews.nl!193.201.147.78.MISMATCH!feeder.news-service.com!tudelft.nl!txtfeed1.tudelft.nl!dedekind.zen.co.uk!zen.net.uk!hamilton.zen.co.uk!proxad.net!feeder2-2.proxad.net!newsfeed.arcor.de!newsspool1.arcor-online.net!news.arcor.de.POSTED!not-for-mail From: "Dmitry A. Kazakov" Subject: Re: Ada noob here! Is Ada widely used? Newsgroups: comp.lang.ada User-Agent: 40tude_Dialog/2.0.15.1 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Reply-To: mailbox@dmitry-kazakov.de Organization: cbb software GmbH References: <2nzpd0skyawr.1qzqs0hgb81yh$.dlg@40tude.net> Date: Mon, 7 Jun 2010 09:48:43 +0200 Message-ID: NNTP-Posting-Date: 07 Jun 2010 09:48:19 CEST NNTP-Posting-Host: 68e85816.newsspool2.arcor-online.net X-Trace: DXC=Za^>TVK16dc:i=48;n?Z:`A9EHlD;3Ycb4Fo<]lROoRa8kF On Sun, 6 Jun 2010 19:27:48 +0000 (UTC), tmoran@acm.org wrote: >>The problem is that to apply this theory to software you need maybe, >>imaginary space of elementary outcomes (independent, complete etc). I don't >>see any of that in the software. It is a fundamental issue. > The number of bugs in a certain piece of software is analogous to the > 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... (:-)) -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de