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=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fac41,2c6139ce13be9980 X-Google-Attributes: gidfac41,public X-Google-Thread: 103376,3d3f20d31be1c33a X-Google-Attributes: gid103376,public X-Google-Thread: f43e6,2c6139ce13be9980 X-Google-Attributes: gidf43e6,public X-Google-Thread: 1108a1,2c6139ce13be9980 X-Google-Attributes: gid1108a1,public From: peb@transcontech.co.uk ("Paul E. Bennett") Subject: Re: The stupidity of all the Ariane 5 analysts. Date: 1997/08/01 Message-ID: <870438757snz@transcontech.co.uk>#1/1 X-Deja-AN: 261276194 References: <33E06929.59F6@easystreet.com> X-Mail2News-Path: tcontec.demon.co.uk Reply-To: peb@transcontech.co.uk X-Mail2News-User: peb@transcontech.co.uk Organization: Transport Control Technology Ltd. Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel Date: 1997-08-01T00:00:00+00:00 List-Id: In article <33E06929.59F6@easystreet.com> achrist@easystreet.com "Al Christians" writes: > > It would be nice if there could be a clear spec that includes everything > that might happen in the real world, but when the real world does > something that the spec didn't anticipate, do we want the software to > just curl up and die? If such a spec could be produced it would probably be too large to understand in reasonable time. Instead, we need to construct our systems so that out-of-the-ordinary stimulii do not cause un-expected activity of the system. This involves knowing what happens in the system when the stimulii exceed the design limitations. This takes some effort in FMECA and the designing in of "Inherent Robustness" for the system to become dependable. If we are going to re-use components, we need to be more certain about what the effects are for component failure. In the A5 flight systems situation, there were other factors in the organisation which blindly accepted the decision for non-provision of flight profiles. A risk assessment for the decision should have been conducted to determine if this was a reasonable decision. -- Paul E. Bennett ................... Transport Control Technology Ltd. +44 (0)117-9499861 Going Forth Safely