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: 101deb,f96f757d5586710a X-Google-Attributes: gid101deb,public X-Google-Thread: f43e6,5ac12f5a60b1bfe X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,5ac12f5a60b1bfe X-Google-Attributes: gid103376,public From: multics@wizvax.wizvax.net (Richard Shetron) Subject: Re: Ariane 5 - not an exception? Date: 1996/07/30 Message-ID: <4tjrit$m8b@news.wizvax.net>#1/1 X-Deja-AN: 171098998 references: <4t9vdg$jfb@goanna.cs.rmit.edu.au> <4tiu6e$kpm@news2.cais.com> organization: Wizvax Communications newsgroups: comp.software-eng,comp.lang.ada,comp.lang.pl1 Date: 1996-07-30T00:00:00+00:00 List-Id: In article <4tiu6e$kpm@news2.cais.com>, Bill Angel wrote: > >In article <4t9vdg$jfb@goanna.cs.rmit.edu.au>, >++ robin wrote: >>In Ariane, both the active processor and the backup failed at >>the same time, because it was a *programming* error that was >>encountered at the same time in both processors, and both >>processors were shut down at the same time by their respective >>error handlers. > > I am under the impression that for the US manned spaceflight >program (to get to the moon) ,an on-board computer that was serving as a >backup to the primary computer would have been performing its computations >using completely different software than the primary computer. By >utilizing this methodology, the same software "glitch" would not halt both >systems simultaneously. Perhaps a group of software developers could be >tasked with producing a version of the on-board software for Ariane in a >different computer language than that used by the primary processor. The >two processors, running simultaneously, would serve to check each other's >results with greater independence that they apparently do now. I've been told that the shuttle uses 5 computers with software developed by 3 independent programming groups. A best 2 out of 3 is used to determine which software/hardware is operating properly.