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#61
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Future of Electronics In Aviation
In rec.aviation.piloting Le Chaud Lapin wrote:
On Jun 20, 6:07?am, Bob Noel wrote: In article , And what analysis techniques would be applied to prove that the resulting software intensive system is adequately safe? The same techniques that employed, in general, by experts to test software. I don't care how many "fastidious" people look at an architecture or the as-built system, if they don't know what they are looking for and how to find it, the odds of proving ?anything useful are pretty small. Well, assuming they are experts, each in their respective areas, they would indeed know what to look for. Also, peer-review (by other experts) is a very good way to check structural integrity of software (or any system). Blue Screen of Death (BSOD). Do I need to say more? -- Jim Pennino Remove .spam.sux to reply. |
#62
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Future of Electronics In Aviation
In rec.aviation.piloting Le Chaud Lapin wrote:
On Jun 20, 8:40?am, "Peter Dohm" wrote: In any case, while process is important, the end result is most important. ?And the end result would be seen by many people, before the aircraft is flown, so most defects would be recognized. ?I would imagine that there would be people who would criticize the architecture for free. -Le Chaud Lapin- There excellent counterexamples all around us--including the computers we are using to send these messages. Think how boring the world would be if the opposite were true, that all software quality were the same (good or bad), no matter who authored it. Having your computer die while in the middle of writting a document, controlling a power plant, running a subway system, or flying an airplane are not events most people look upon as providing positive excitement to life. -- Jim Pennino Remove .spam.sux to reply. |
#63
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Future of Electronics In Aviation
Le Chaud Lapin wrote:
For XC flights, a computer can do a far better job optimizing fuel efficiency, for example, by controlling control surfaces dynamically during flight. A computer can also minimize the effects of turbulence, by reactively changing the same control surfaces dynamically. Can you actually cite some numbers and studies or are you just making this stuff up? It was proven back in the 30's or 40's that after an airplane flies into a pocket of turbulence, it's too late for either a pilot or a computer to make much difference. The *only* way to fix the problem is with a 20-30 foot boom ahead of the aircraft structure that can sense and react to the turbulence ahead of time. As to fuel economy, perhaps you can tell me how a computer could tune the radio and get winds aloft readings and pick the best altitude for cruise? Since it can't, it is unlikely that it could do a better job than a pilot. OTOH, if you have some concrete evidence to the contrary, I'd love to see it. |
#64
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Future of Electronics In Aviation
In rec.aviation.piloting Le Chaud Lapin wrote:
On Jun 20, 5:16?am, Dylan Smith wrote: On 2008-06-19, Le Chaud Lapin wrote: 3. Do you think electronics should retain a peripheral role ? (Garmin, etc) but not be used in control paths (fly-by-wire)? Fly by wire is pretty pointless on the kinds of planes we fly, it's adding complexity where none is needed and steel cables and pulleys are pretty reliable in airplanes, and pushrods to the swash plate in a helicopter seem very reliable too. Changing those to electronics would have pretty much zero benefit in a light airplane or helicopter (and some significant disadvantages). I disagree. Because apparently you know nothing about real flying. For XC flights, a computer can do a far better job optimizing fuel efficiency, for example, by controlling control surfaces dynamically during flight. A computer can also minimize the effects of turbulence, by reactively changing the same control surfaces dynamically. A computer can take any of many objectives defined by pilot: 1. Minimum time in flight. 2. Minimum fuel consumption. 3. Altitude stabilization. 4. Minimum susceptibility to turbulence. 5. Maximum visibility of surroundings. Total, utter nonsense. etc... And make the flight conform to those requirements, and warn if it can not. That very same computer could communicate flight plan to ground, store minute details of entire flight on hard disk and automatically move them to home computer for recap.... Control electronics does exist for GA, it's called an autopilot, and they've been around for a long time (some more sophisticated than others). Some engines are also available with FADEC. These systems are massively expensive, and there is much redundancy. For example, the entire radio stack could be eliminated by a software radio, which controls fed through LCD monitor. The software radi costs $1000. The computer would be one of same 2 computers used for other functions. Yeah, for one Amateur Radio grade software radio with you supplying the computer. The possibilities are essentially endless. GA is at the beginning, not the end, of discovering them. Especially for someone who gets their ideas from comic books. -- Jim Pennino Remove .spam.sux to reply. |
#65
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Future of Electronics In Aviation
On Jun 20, 11:35*am, wrote:
In rec.aviation.piloting Le Chaud Lapin wrote: On Jun 20, 8:40?am, "Peter Dohm" wrote: In any case, while process is important, the end result is most important. ?And the end result would be seen by many people, before the aircraft is flown, so most defects would be recognized. ?I would imagine that there would be people who would criticize the architecture for free. -Le Chaud Lapin- There excellent counterexamples all around us--including the computers we are using to send these messages. Think how boring the world would be if the opposite were true, that all software quality were the same (good or bad), no matter who authored it. Having your computer die while in the middle of writting a document, controlling a power plant, running a subway system, or flying an airplane are not events most people look upon as providing positive excitement to life. Every machine can fail. What matters so much is not whether the machine is a computer or something else, but the probability of failure of that component, and the probability of failure of the overall system as a result. I read on regular basis about ICE's that failed for whatever reason. But people still use ICE's. One should look at the math of each situation and do what is necessary to make likelihood of system failure at least equivalent. -Le Chaud Lapin- |
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Future of Electronics In Aviation
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#67
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Future of Electronics In Aviation
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#68
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Future of Electronics In Aviation
In article
, Le Chaud Lapin wrote: On Jun 20, 6:07*am, Bob Noel wrote: In article , And what analysis techniques would be applied to prove that the resulting software intensive system is adequately safe? The same techniques that employed, in general, by experts to test software. And exactly what level of reliability do you think you'll need to have? Note that the cost can rise enormously for fairly small increases in end product reliability. And so far we haven't said much about what the lawyers will bring to your nifty new product. (Trust me, it won't be something to make you emit small cries of joy.) I don't care how many "fastidious" people look at an architecture or the as-built system, if they don't know what they are looking for and how to find it, the odds of proving *anything useful are pretty small. Well, assuming they are experts, each in their respective areas, they would indeed know what to look for. Also, peer-review (by other experts) is a very good way to check structural integrity of software (or any system). You *really* don't know what is involved in developing verifiably correct software systems, either in time or money. It's *very* difficult and expensive. |
#69
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Future of Electronics In Aviation
In rec.aviation.piloting Le Chaud Lapin wrote:
On Jun 20, 11:35?am, wrote: In rec.aviation.piloting Le Chaud Lapin wrote: On Jun 20, 8:40?am, "Peter Dohm" wrote: In any case, while process is important, the end result is most important. ?And the end result would be seen by many people, before the aircraft is flown, so most defects would be recognized. ?I would imagine that there would be people who would criticize the architecture for free. -Le Chaud Lapin- There excellent counterexamples all around us--including the computers we are using to send these messages. Think how boring the world would be if the opposite were true, that all software quality were the same (good or bad), no matter who authored it. Having your computer die while in the middle of writting a document, controlling a power plant, running a subway system, or flying an airplane are not events most people look upon as providing positive excitement to life. Every machine can fail. True but irrelevant. What matters so much is not whether the machine is a computer or something else, but the probability of failure of that component, and the probability of failure of the overall system as a result. And establishing that probablility is generally an extremely expensive process. I read on regular basis about ICE's that failed for whatever reason. But people still use ICE's. Irrelevant One should look at the math of each situation and do what is necessary to make likelihood of system failure at least equivalent. Already been done. It is called FAA certification requirements. -- Jim Pennino Remove .spam.sux to reply. |
#70
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Future of Electronics In Aviation
On Jun 20, 12:01*pm, Jim Logajan wrote:
wrote: In rec.aviation.piloting Le Chaud Lapin wrote: On Jun 19, 9:54?pm, Bob Noel wrote: [...] What makes you think that software engineering, or system engineering, has progressed to the point that a software intensive system would be developed "with proper discipline"? That's fair enough. Software, perhaps more than any other discpline, allows engineers to place themselves where they are most comfortable on the spectrum of intellectual discipline. [...] In any case, while process is important, the end result is most important. *And the end result would be seen by many people, before the aircraft is flown, so most defects would be recognized. *I would imagine that there would be people who would criticize the architecture for free. From the perspective of dealing with software development for about a quarter century now, all I can say is that it is obvious you know **** from shinola about software development, reliability, and testing. Well I've been programming for 35 years and been getting paid to do it for 30, so by your own metric I am presumably in some sort of authoritative position to judge your counter arguments to Lapin re software development. But I somehow doubt you really want to know what I think of your arguments.. ;-) Please, do tell. Being in software field, you know that there are people who have been programming for 40 years whom you would not trust to design a flight control computer that relies on advanced mathematics. Obviously not saying that you are in that category. I'm merely saying that I would look for other personal attributes beyond experience that makes an engineer/designer predisposed to not make a mess, someone who is acutely aware of the potential outcome of bad engineering. That person might or might not have 35 years of experienece, but if I had to choose between the Dutch guy mentioned above, who probably has 12-15 years experience,, and a random senior engineer with 40 years experience, I would not hesitate to choose the Dutch guy, simply because I already know that he possesses these attributes. -Le Chaud Lapin- |
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