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| IL-2 Sturmovik The famous combat flight simulator. |
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#1
10-06-2010, 06:54 AM
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From Mariner 1 via Ariane 5 to the SAAB Gripen prototype, the history of software in aviation is dismal. If a civil engineer built a bridge that collapsed, he'd be ruined. A software engineer builds his bridge again and again - hundreds of times - and when it finally stands up on its own there's a big party.
Thankfully physical modelling like Il-2/SoW has a better record than most, but many large software projects exhibit not just a lack of competence but a lack of understanding of the most basic precepts of engineering. It's not just that many big IT projects end up non-functional, they start out with designs that couldn't function in the first place. Computer Science grads need to be taught the difference between provable and non-provable designs and how to test ideas. dduff 
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#2
10-06-2010, 07:04 AM
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The software industry is more akin to book or music publishing then any of the more traditional "professions" .
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#3
10-06-2010, 07:32 AM
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 Regulations are an interesting topic, I think what prevents a lot of mistakes within engineering are the numbers of people that check the designs, which is often the exact opposite with programming. I don't see a reason to impose regulations on non-safety critical programmers though.
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#4
10-06-2010, 12:15 PM
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I remember following experiment, which involved braking in snow, with and without ABS, with and without winter tires. ABS vs conventional, winter tires: ABS<conventional ABS vs conventional, summer tires: Conventional<ABS The latter is explained by the conventional wheel locking up, building a wedge of snow in front of the tires which increases friction. The ABS however is confused, because then summer tires can't get any grip on the snow - and the ABS doesn't want to let them slip, as result the brake stays open... Is it possible your camry had shitty tires?
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#5
10-06-2010, 12:34 PM
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Who knows... it wasn't his Camry.
But anyway, the argument wasn't against ABS, which can be switched off (in the models I drive in, 1 circuit breaker) but the total absence of a hydraulic/mechanical linkage to the pereiopodical appendage (leg). Even a hydraulic system with a leak or a faulty brake vacuum pump will stop your car but if you are pushing the pedal linked to a rheostat while you've lost complete electrical power, maybe smashing your windscreen and blowing in the wind might help (choose your context). Last edited by Azimech; 10-06-2010 at 12:46 PM.
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#6
10-06-2010, 01:05 PM
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But they could design it like pneumatic truckbrakes where your need the air pressure(in our case epower) to keep the brakes open - if their system leaks air, the truck just brakes and stops.
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#7
10-06-2010, 01:19 PM
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Keep in mind the pneumatic brake system of a truck is very complex and redundant, with two pressure gauges which a driver is trained to check and act upon. All (competent and awake) drivers will stop the truck before the brakes kick in, at a safe location with opportunity to warn the traffic behind him. I had to learn this stuff.
If a car loses all power and starts braking, it could be at an unsafe spot, without emergency and brake lights. That could lead to utter disaster, especially on a dark, wet road (in a corner, on a downwards slope, etc.) Even if the system has some kind of a capacitor and warns the driver before the brakes kick in, a lot of people ignore warning lights, interpret them wrong or simply have no clue what it means. My mother is notorious. If I didn't fill up her engine oil every now and then, she called me with the message that a combination of four lights (yes, the Citroën BX does that) came on during corners. Zero oil pressure. I've explained to her a dozen times what it means, that the manual is in the glove compartment, the oil in the trunk and how to fill up the engine. She just doesn't want to remember I guess. Finally I gave up and just bought her a different BX that doesn't use oil at all. Last edited by Azimech; 10-06-2010 at 01:29 PM.
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#8
10-06-2010, 11:36 PM
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I don't claim to know about ABS and snow... I don't drive through any - but my mate's cars with ABS have each become (a little dangerously) confused on loose dirt roads, which we frequent. Hence as Azimech mentioned, they take out the ABS fuse, and regain predictable brakes.
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#9
10-06-2010, 07:32 AM
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#10
10-06-2010, 08:34 AM
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The claim that computers do things that have never been done before is dubious... Alan Turing determined universally exactly what computers could do. Other mathematicians determined things that computers could *not* do -- NP complete problems etc. I don't know a massive amount about any of this, but its fair to say that Turing spoke a totally different language to software engineers. It's reasonable to question the fairness of the jibe I made -- usually nobody need die because a computer programme crashes, unlike with collapsing bridges. Some of the excuses made by the industry don't stand up to criticism, however. Taking the internet as an example, it was built by electronics and fibre optics specialists and jpeg/mp3 etc (all basically the same tech) made it fast, cheap and economical. Microsoft and Netscape, OTOH, bequeathed us javascript, popups and security holes. Even when I think of the internet myself I think software, but it's an illusion. The hardware basically always works reliably but its invisible. The software types control the branding and somehow come away with all the cash... dduff
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