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: 103376,5ac12f5a60b1bfe X-Google-Attributes: gid103376,public X-Google-Thread: f43e6,5ac12f5a60b1bfe X-Google-Attributes: gidf43e6,public From: "Theodore E. Dennison" Subject: Re: Ariane 5 - not an exception? Date: 1996/07/26 Message-ID: <31F8FD5F.41C67EA6@escmail.orl.mmc.com>#1/1 X-Deja-AN: 170318247 references: content-type: text/plain; charset=us-ascii organization: Lockheed Martin Information Systems mime-version: 1.0 newsgroups: comp.software-eng,comp.lang.ada x-mailer: Mozilla 2.0 (X11; I; SunOS 4.1.3_U1 sun4m) Date: 1996-07-26T00:00:00+00:00 List-Id: Simon Bluck wrote: > > It is most unfortunate, but must be accepted as true, that if the > Ariane software had been written in a less powerful language the > numeric overflow might have gone unnoticed, the computers would have > remained switched on, and the rocket would have continued its upward > flight. If the Ariane software had been written in a less powerful language, the overflow might have gone unnoticed, while writing garbage in a nearby data/code location. This could easily have caused the exact same result, with the important difference that the committe could never have isolted the problem as well as they did. > You _never_ switch off a computer, but you may have cause to mark all > data emanating from it as suspect. Leave it up to the users of the > data to decide if they want to use it or not - they may have no > choice. Silly. If you _never_ switch over to the standby computer, there is no point to having it, is there? I could see the logic in rewriting the code on the backup machine to try to continue with "best effort" data when an error is detected, but I can't agree with the logic that the primary machine should continue to spit out data, even when it knows it has errors (and there is a backup machine available), which is what the committe seems to be suggesting. -- T.E.D. | Work - mailto:dennison@escmail.orl.mmc.com | | Home - mailto:dennison@iag.net | | URL - http://www.iag.net/~dennison |