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=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.42.60.75 with SMTP id p11mr38644382ich.10.1430652224101; Sun, 03 May 2015 04:23:44 -0700 (PDT) X-Received: by 10.140.20.40 with SMTP id 37mr166012qgi.26.1430652222960; Sun, 03 May 2015 04:23:42 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!mx02.eternal-september.org!feeder.eternal-september.org!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!peer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!l13no13252017iga.0!news-out.google.com!k20ni1195qgd.0!nntp.google.com!z60no4814811qgd.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Sun, 3 May 2015 04:23:42 -0700 (PDT) In-Reply-To: <201505021834588468-rblove@airmailnet> Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=213.108.152.51; posting-account=bMuEOQoAAACUUr_ghL3RBIi5neBZ5w_S NNTP-Posting-Host: 213.108.152.51 References: <201505021834588468-rblove@airmailnet> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <9f20f713-d65c-471d-ab7c-d314a14fdcd0@googlegroups.com> Subject: Re: Boeing 787 integer overflow From: Maciej Sobczak Injection-Date: Sun, 03 May 2015 11:23:42 +0000 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Received-Bytes: 3033 X-Received-Body-CRC: 3075239223 Xref: news.eternal-september.org comp.lang.ada:25702 Date: 2015-05-03T04:23:42-07:00 List-Id: W dniu niedziela, 3 maja 2015 01:34:59 UTC+2 u=C5=BCytkownik Robert Love na= pisa=C5=82: > Ars Tecnica has this article: >=20 > http://arstechnica.com/information-technology/2015/05/01/boeing-787-dream= liners-contain-a-potentially-catastrophic-software-bug/=20 >=20 >=20 > Can anyone comment on what language Boeing used for this? It does not matter. The ability to run continuously for 8 months was most l= ikely not in the requirements (planes have to be switched off for maintenan= ce more frequently than that anyway), so there was no need to implement a s= olution for this. You can safely argue that the capacity of the counter all= ows proper operation within the given bounds and you could even have that t= ested with 100% coverage of the *required* data/time domain and (why not?) = formally verified as well. > If Ada, would a modular integer be more appropriate? Why? Are you aware of the requirement that the counter has to automatically= reset after (let's say) half a year? I guess not and even if you attempt t= o make it up as a derived requirement, it might be superfluous or even cont= radictory to other requirements. > Is there an=20 > exception handler for this integer? Why? Are there any requirements that explicitly state the plane has to work= continuously for longer than 8 months? Ada is not a solution to this problem, because this is really not a problem= (unless shown at the level of requirements). The whole article is only an = opportunity for journalists to write something exciting and then Boeing has= to react somehow purely for PR reasons, even if, from the engineering pers= pective, they don't actually have to. Of course, if it appears that this part of the system was indeed written in= Ada, you can expect Ada skeptics to have a similar ride as with Ariane V. --=20 Maciej Sobczak * http://www.inspirel.com