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,LOTS_OF_MONEY autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,703c4f68db81387d X-Google-Thread: 109fba,703c4f68db81387d X-Google-Thread: 115aec,703c4f68db81387d X-Google-Thread: f43e6,703c4f68db81387d X-Google-Attributes: gid103376,gid109fba,gid115aec,gidf43e6,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!postnews.google.com!z14g2000cwz.googlegroups.com!not-for-mail From: "Jerry Coffin" Newsgroups: comp.lang.ada,comp.lang.c++,comp.realtime,comp.software-eng Subject: Re: Teaching new tricks to an old dog (C++ -->Ada) Date: 28 Mar 2005 01:09:48 -0800 Organization: http://groups.google.com Message-ID: <1112000988.566574.80420@z14g2000cwz.googlegroups.com> References: <871xau9nlh.fsf@insalien.org> <3SjWd.103128$Vf.3969241@news000.worldonline.dk> <87r7iu85lf.fsf@insalien.org> <1110052142.832650@athnrd02> <1110284070.410136.205090@o13g2000cwo.googlegroups.com> <395uqaF5rhu2mU1@individual.net> <1111607633.301232.62490@z14g2000cwz.googlegroups.com> <1111628011.160315.134740@o13g2000cwo.googlegroups.com> <1111732101.995662.309040@z14g2000cwz.googlegroups.com> <1111785256.454375.76600@l41g2000cwc.googlegroups.com> <1369131.HYMxOlSdZt@linux1.krischik.com> <1111868963.494133.291150@g14g2000cwa.googlegroups.com> <1111951298.083776.80510@l41g2000cwc.googlegroups.com> NNTP-Posting-Host: 68.64.130.76 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1112000992 31526 127.0.0.1 (28 Mar 2005 09:09:52 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Mon, 28 Mar 2005 09:09:52 +0000 (UTC) User-Agent: G2/0.2 Complaints-To: groups-abuse@google.com Injection-Info: z14g2000cwz.googlegroups.com; posting-host=68.64.130.76; posting-account=mZiOqwwAAAC5YZsJDHJLeReHGPXV5ENp Xref: g2news1.google.com comp.lang.ada:10060 comp.lang.c++:47572 comp.realtime:1766 comp.software-eng:5398 Date: 2005-03-28T01:09:48-08:00 List-Id: Chad R. Meiners wrote: > Jerry Coffin wrote > > I was talking specifically about Airbus' use, and looking at: > >http://www.esil.univ-mrs.fr/~spc/rcs02/slides/Baufreton.pdf > >and: > >http://www.systemes-critiques.org/jslc2001_slides/FrancoisXavier_Dorm... > >indicates that they're consistently using C, not Ada. > > No the slides do not indicate this. For all we know the project that > the slides are talking about has to target hardware for which there > is only a C compiler. It could be that Airbus only uses such tools > on such hardware. First of all, at least in my dictionary, "indicate" is defined with words like "points to" and "suggests", NOT "proves" or anything very similar. Second, I have to wonder whether you really have a good idea of the size of project we're talking about. Just for example, Airbus is currently working on the A350, which is fairly based fairly closely on the A340, to the point that it's expected to share a common type rating with the 340 (meaning as far as flying them goes, they're considered the same plane). Despite that derivation, the A350 is expected to take about 6 years and cost (at least) 3,500,000,000 Euros to develop. Developing an entirely new plane runs in the vicinity of twice that. This leads to two points: first of all, neither Airbus nor anybody else is designing hundreds or even dozens of these at a time -- IOW, knowing what they're doing in only one or two projects really _does_ tell you a lot about what the company as a whole is doing, and for an extended period of time at that. Second, unless porting Ada compilers is a LOT more expensive than porting C++ compilers, pre-existing availability of a particular compiler is NOT much of a consideration for this size of project. Just for the sake of argument, let's assume a compiler port costs a half million US dollars. If you figure that up in terms of how time spent on the project, it comes to a matter of hours -- i.e. the compiler port would only have to save them a couple of hours overall to pay for itself. Now, it's certainly true that software alone doesn't account for nearly all the expenditure -- but it's significant enough to figure in the same basic terms. The compiler might have to save a whole day to pay for itself, but almost certainly would not have to save (say) a whole month to pay off. > Using presentation slides as such an indicator is usually a bad idea. > Presentation slides are made for a specific context, and time frame. > They often lack full and complete information. The slides don't > explicitly support your claim. I'll openly admit that the slides don't absolutely _prove_ nearly as much as we'd like to know. They're generally vague, lacking detail, definition or rigor -- but despite that they still constitute roughly 95% of the hard evidence presented so far in this entire thread! -- Later, Jerry. The universe is a figment of its own imagination.