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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,885dab3998d28a4 X-Google-Attributes: gid103376,public From: Ken Garlington Subject: Re: Ariane 5 failure Date: 1996/10/10 Message-ID: <325D418F.49B5@lmtas.lmco.com>#1/1 X-Deja-AN: 188729341 references: <96100111162774@psavax.pwfl.com> <32555A39.E38@lmtas.lmco.com> content-type: text/plain; charset=us-ascii organization: Lockheed Martin Tactical Aircraft Systems mime-version: 1.0 newsgroups: comp.lang.ada x-mailer: Mozilla 2.02 (Macintosh; I; 68K) Date: 1996-10-10T00:00:00+00:00 List-Id: Robert Dewar wrote: > > I find the second outcome here unacceptable, so the methodology must simply > prevent such errors completely. Indeed if you look at safety critical > subsets for Ada they often omit exceptions precisely because of this > consideration. After all exceptions make the language and compiler more > complex, and that itself may introduce concerns at the safety critical > level. I'm also starting to be convinced, after some anecdotal evidence with the systems I work, that _suppressing_ checks can also make the compiler more fragile. My guess is that fewer people in general suppress all checks for most compilers, so those paths in the compiler that run with checks suppressed are used less often, and so they have a higher probability of containing bugs. I also suspect that most vendors do not run their standard tests suites (including ACVCs) with checks suppressed (how could you, for the part of the test suite that validates exception raising and handling?), so there's less coverage from that source as well. I'm not saying that it's dumb to suppress checks (or not suppress checks) for safety-critical systems. I'm just saying the answer appears to be a lot more complicated than I thought it was 10 years ago (or even 2 years ago). -- LMTAS - "Our Brand Means Quality" For more info, see http://www.lmtas.com or http://www.lmco.com