On this side of the world, corporations are forced (by law) to care so much about safety that you need induction and training for working at extreme heights to program a PLC in a substation on a mine with both feet planted firmly on the ground(Can be bypassed with social engineering...:) ). Sometimes I even wonder if the American way is better or not...
In any case I am glad to hear that these things were built properly. Even if you can't cure stupid without terminating the subject..
I would imagine a combination of social engineering and physical access can bridge that particular gap. But sometimes engineers get lazy and do stupid things like forgetting hardware interlocks. I have seen SCADA systems connected to the raw internet (without even a firewall). Just because it shouldn't be done doesn't mean it isn't.
Is it necessary to break these particular eggs? Is it sane? And is it in your best interests? Think for two seconds about the consequences of your actions.
Please people. Do not screw with industrial control systems. They are interlocked (hopefully in hardware as well, but not always) for safety. Messing with them can actually kill people. And lets hope they're not connected to the net at disney world. I hate copyright abuse as much as the next guy, but do you really want to start terrifying and killing kids on disney world rides? That is so messed up. Its one thing to hit a RIAA website, another to screw with something powerful that you don't really understand.
My EE degree included everything from ladder logic to C++. And we were taught to make our programs as clear and concise as possible, but then, I come from a completely different world...
Actually the flicker on those monitors was often traceable back to the flicker from the lights; when the 50/60hz mains '0' coincided with a scan rate, the flicker becomes obvious. It wasn't so much the refresh rate, but the fact that there was an interference pattern. At higher frequencies, the phosphor had less time to fade, so the dip in brightness became less obvious(except at low ambient light levels...). Remember a LCD has no fading effect,so much lower frequencies are now acceptable.
However, he is wrong. The human eye can perceive all sorts of things. Often you won't be able to say what it is, but it is annoying and can cause headaches. 24fps can be compensated for in various ways - immersion, and using synced sound to distract the brain from the flicker. If the person is talking and the sound comes at the right time, your brain will smooth it out for you...
That only covers mistakes like typos. The bugs independent systems do not cover are logical and conceptual errors. If the functional specification is wrong to start with, all the versions will have similar or identical issues. Fail safe is a tricky thing in an aircraft. Systems and sensors will fail. No matter how many or how well designed. If two out of three air speed sensors fail for example, then there will be big problems. The point being that there is no 100% safety.
I'm sure they must have more than one sensor. Perhaps even more than one sensing principle is involved. The problem with the system of having multiple computers vote, is we tend to solve problems in similar ways, so if there is a logic error in one machine (as opposed to a typo) it is fairly likely to be repeated in at least 2 of the other machines. Some sets of conditions are very hard to predict and design for. Even in the most simple systems. I often see code (when updating a system) that does not account for every possibility because either everyone considers that combination unlikely, or nobody thought of it in the first place(until it happens of course...) Being a perfectionist in this business is very costly in development time.
The fact is a complex system such as an aircraft could easily be beyond human capability to perfect first time. And test completely.
Mod parent up. Anyhow, information from a sensor may be valid but inaccurate. I deal with these types of systems regularly(not in aircraft, but control systems in general), and it is sometimes impossible to tell with out extra sensors. Its one thing to detect a "broken wire" fault, and a completely different thing to detect a 20% calibration fault, for example, so validity checking can only take you so far. Its actually impressive the failure mode in this case caused so little damage.
I am not convinced you know what a SCADA is? At most a SCADA can set bits/words in a PLC. Not, reprogram them (unless it is siemens, but we don't talk about that dark festering evil - microsoft has nothing on those guys). I have in fact never seen a SCADA that could be used to program a PLC - the program is already in the PLC, the SCADA may then be used to change the behavior of that program.. The SCADA's primary goal is being an interface between the PLC and the operator (just like a dedicated HMI - which is often a windows/dos/*nix machine with a touch screen in a special case). Normally you just set up a separate LAN with an air-gap though in a nuclear facility it may be somewhat different.
PLCs are the way to go here. And they are tried, tested and proven. And probably run most of the world's existing semi-modern nuclear or other power plants. Though to be fair, its probably Mitsubishi not Omron PLCs that run everything.
The beauty of the PLC, is that it can implement your tested legacy relay control system without much re-engineering or destructive testing. And they are the most robust electronics I have ever seen, surviving very harsh conditions, temperatures, humidities. I know of one that continued to function (until the power supply gave up) while submersed in slurry.
Oh, and if you've ever worked in the industry you'll know it'll be RS485. RS232 sucks for industrial use. Often the extension to RS485, DeviceNet. In a nuclear facility your remote IO would also be intelligent - so that when comms fails(we assume it will), you can intelligently fail safe.
Unless you were as thick as two short planks(and many sadly are), you would never ever ever ever run a nuclear plant on windows. Or even linux. Or even siemens hardware in general. You would use a robust PLC from someone like Omron and some dedicated HMIs to backup your SCADA, which will sadly run windows. The PLC program should be properly interlocked and fail safe. The plant runs on the PLC not the SCADA.
I find other people's views interesting and speculative fiction on how they react to differing situations is interesting to me. This for example, is an interesting question, how would christian fundamentalists react? How would muslims?
This is yet another interesting scenario. To me, at least. You may have no interest in how people who disagree with you think and react, but that however is your loss. Science fiction is very good at exploring such ideas. Perhaps you're not a fan of science fiction?
Modern Christians non fundamentalist seem to take the view that the "image" we're created in reflects the spiritual, moral and logical nature of God rather than a physical image. So, it isn't theologically impossible for an alien to be thought of as "in the image of God" even if it's eyes are on stalks and its green.
If you read the link, you'll realize that the catholic church has an official position on aliens and what to do if contact is made. Most fundamentalists are too self centered to have even though about beyond a knee-jerk "its a demon!" reaction, so in a sense, he is sadly correct. I sit corrected by AC. How embarrassing.
I find it sad that writers fear to explore religion in speculative fiction. The reaction (specifically of the majority of Christians -i.e. catholics) may not be what you think it is.
I went to school to become a programmer, I would have failed if I didn't show up for Math, even though I almost never use it as a System Developer now a few years after.
??!!! How do you not use math? I develop a whole range of systems on a variety of hardware from PLCs(ladder logic) to C++ on windows. I could not operate without math. And I don't just mean simple math, I mean complex stuff as well.
I see no problem in failing doctors cause they do not show up to Darvin class, I would not want to be treated by a Doctor that does not understand the body, and I am sure our customers would not like a programmer that don't know any Math.
The real question, I guess, is how necessary is evolution in understanding the body. Math is 100% necessary to understand computers, but is evolution 100% necessary to understand the body as it is?
It all depends on the costs involved. I know of a place that spends a fortune shipping and buying about 4 tonnes(metric) a day of salt to save water(their water reclamation system doesn't work without it, because of some chemicals in the process). That's not cheap, but its cheaper than all the alternatives. But the situation is different and the economics will be for your farmer. It may make sense there(or it may not, some stupid systems run daily), but with smart metering, it works out cheaper in all cases I've seen to hire some guy to go read the thing than to use cell phone comms. Normally (in this part of the world at least, and perhaps in America too, since we get meters from international suppliers) the meter company stores and processes half hour billing profile data for each customer(the large ones at least), and that is quite a lot of data. At the data rates I've see for either here or America, even assuming a 50% bulk discount, that is a lot of money compared to some bloke in a truck driving around witlessly collecting the data..... but YMMV.
Slashdot Mirror
Wait, what? Quantumn computers are supernatural?
Siemens? You have my pity sir. Siemens PLCs are terrible. No clue why they're so popular...
PLCs are the natural "evolution"(if you like) of Relay control logic. Which dates to pre WWII. That is why they use ladder diagrams.
On this side of the world, corporations are forced (by law) to care so much about safety that you need induction and training for working at extreme heights to program a PLC in a substation on a mine with both feet planted firmly on the ground(Can be bypassed with social engineering... :) ). Sometimes I even wonder if the American way is better or not...
In any case I am glad to hear that these things were built properly. Even if you can't cure stupid without terminating the subject..
(if this was a tasteless joke, though, I'll whoosh myself. Several beers since I posted originally.....)
I submit to you that no one would die who otherwise would not have eventually.
So(if we grant your submission), then the loss of life equates to a loss of people's time. Still unethical. Try again.
I would imagine a combination of social engineering and physical access can bridge that particular gap. But sometimes engineers get lazy and do stupid things like forgetting hardware interlocks. I have seen SCADA systems connected to the raw internet (without even a firewall). Just because it shouldn't be done doesn't mean it isn't.
Is it necessary to break these particular eggs? Is it sane? And is it in your best interests? Think for two seconds about the consequences of your actions.
Please people. Do not screw with industrial control systems. They are interlocked (hopefully in hardware as well, but not always) for safety. Messing with them can actually kill people. And lets hope they're not connected to the net at disney world. I hate copyright abuse as much as the next guy, but do you really want to start terrifying and killing kids on disney world rides? That is so messed up. Its one thing to hit a RIAA website, another to screw with something powerful that you don't really understand.
My EE degree included everything from ladder logic to C++. And we were taught to make our programs as clear and concise as possible, but then, I come from a completely different world...
No, no, this is abuse. You want room 12b.
Actually the flicker on those monitors was often traceable back to the flicker from the lights; when the 50/60hz mains '0' coincided with a scan rate, the flicker becomes obvious. It wasn't so much the refresh rate, but the fact that there was an interference pattern. At higher frequencies, the phosphor had less time to fade, so the dip in brightness became less obvious(except at low ambient light levels...). Remember a LCD has no fading effect,so much lower frequencies are now acceptable.
However, he is wrong. The human eye can perceive all sorts of things. Often you won't be able to say what it is, but it is annoying and can cause headaches. 24fps can be compensated for in various ways - immersion, and using synced sound to distract the brain from the flicker. If the person is talking and the sound comes at the right time, your brain will smooth it out for you...
That only covers mistakes like typos. The bugs independent systems do not cover are logical and conceptual errors. If the functional specification is wrong to start with, all the versions will have similar or identical issues. Fail safe is a tricky thing in an aircraft. Systems and sensors will fail. No matter how many or how well designed. If two out of three air speed sensors fail for example, then there will be big problems. The point being that there is no 100% safety.
I'm sure they must have more than one sensor. Perhaps even more than one sensing principle is involved. The problem with the system of having multiple computers vote, is we tend to solve problems in similar ways, so if there is a logic error in one machine (as opposed to a typo) it is fairly likely to be repeated in at least 2 of the other machines. Some sets of conditions are very hard to predict and design for. Even in the most simple systems. I often see code (when updating a system) that does not account for every possibility because either everyone considers that combination unlikely, or nobody thought of it in the first place(until it happens of course...) Being a perfectionist in this business is very costly in development time.
The fact is a complex system such as an aircraft could easily be beyond human capability to perfect first time. And test completely.
Mod parent up. Anyhow, information from a sensor may be valid but inaccurate. I deal with these types of systems regularly(not in aircraft, but control systems in general), and it is sometimes impossible to tell with out extra sensors. Its one thing to detect a "broken wire" fault, and a completely different thing to detect a 20% calibration fault, for example, so validity checking can only take you so far. Its actually impressive the failure mode in this case caused so little damage.
I am not convinced you know what a SCADA is? At most a SCADA can set bits/words in a PLC. Not, reprogram them (unless it is siemens, but we don't talk about that dark festering evil - microsoft has nothing on those guys). I have in fact never seen a SCADA that could be used to program a PLC - the program is already in the PLC, the SCADA may then be used to change the behavior of that program.. The SCADA's primary goal is being an interface between the PLC and the operator (just like a dedicated HMI - which is often a windows/dos/*nix machine with a touch screen in a special case). Normally you just set up a separate LAN with an air-gap though in a nuclear facility it may be somewhat different.
PLCs are the way to go here. And they are tried, tested and proven. And probably run most of the world's existing semi-modern nuclear or other power plants. Though to be fair, its probably Mitsubishi not Omron PLCs that run everything.
The beauty of the PLC, is that it can implement your tested legacy relay control system without much re-engineering or destructive testing. And they are the most robust electronics I have ever seen, surviving very harsh conditions, temperatures, humidities. I know of one that continued to function (until the power supply gave up) while submersed in slurry.
Oh, and if you've ever worked in the industry you'll know it'll be RS485. RS232 sucks for industrial use. Often the extension to RS485, DeviceNet. In a nuclear facility your remote IO would also be intelligent - so that when comms fails(we assume it will), you can intelligently fail safe.
Sure, but AC was implying you might run something like a nuclear reactor on windows. Which is ludicrously stupid.
Unless you were as thick as two short planks(and many sadly are), you would never ever ever ever run a nuclear plant on windows. Or even linux. Or even siemens hardware in general. You would use a robust PLC from someone like Omron and some dedicated HMIs to backup your SCADA, which will sadly run windows. The PLC program should be properly interlocked and fail safe. The plant runs on the PLC not the SCADA.
There are more explorations in christianity then elsewhere, I have not seen so much for other religions...
I find other people's views interesting and speculative fiction on how they react to differing situations is interesting to me. This for example, is an interesting question, how would christian fundamentalists react? How would muslims?
This is yet another interesting scenario. To me, at least. You may have no interest in how people who disagree with you think and react, but that however is your loss. Science fiction is very good at exploring such ideas. Perhaps you're not a fan of science fiction?
Modern Christians non fundamentalist seem to take the view that the "image" we're created in reflects the spiritual, moral and logical nature of God rather than a physical image. So, it isn't theologically impossible for an alien to be thought of as "in the image of God" even if it's eyes are on stalks and its green.
If you read the link, you'll realize that the catholic church has an official position on aliens and what to do if contact is made. Most fundamentalists are too self centered to have even though about beyond a knee-jerk "its a demon!" reaction, so in a sense, he is sadly correct. I sit corrected by AC. How embarrassing.
This is an interesting read.
I find it sad that writers fear to explore religion in speculative fiction. The reaction (specifically of the majority of Christians -i.e. catholics) may not be what you think it is.
I went to school to become a programmer, I would have failed if I didn't show up for Math, even though I almost never use it as a System Developer now a few years after.
??!!! How do you not use math? I develop a whole range of systems on a variety of hardware from PLCs(ladder logic) to C++ on windows. I could not operate without math. And I don't just mean simple math, I mean complex stuff as well.
I see no problem in failing doctors cause they do not show up to Darvin class, I would not want to be treated by a Doctor that does not understand the body, and I am sure our customers would not like a programmer that don't know any Math.
The real question, I guess, is how necessary is evolution in understanding the body. Math is 100% necessary to understand computers, but is evolution 100% necessary to understand the body as it is?
That site is line of sight...
It all depends on the costs involved. I know of a place that spends a fortune shipping and buying about 4 tonnes(metric) a day of salt to save water(their water reclamation system doesn't work without it, because of some chemicals in the process). That's not cheap, but its cheaper than all the alternatives. But the situation is different and the economics will be for your farmer. It may make sense there(or it may not, some stupid systems run daily), but with smart metering, it works out cheaper in all cases I've seen to hire some guy to go read the thing than to use cell phone comms. Normally (in this part of the world at least, and perhaps in America too, since we get meters from international suppliers) the meter company stores and processes half hour billing profile data for each customer(the large ones at least), and that is quite a lot of data. At the data rates I've see for either here or America, even assuming a 50% bulk discount, that is a lot of money compared to some bloke in a truck driving around witlessly collecting the data..... but YMMV.