So: they don't have an e-mail address for you, or a phone number, and you throw out all postal mail you get from them. How do you suggest they contact you if there's a problem? I wouldn't be in favor of overuse of this method, but if you've got a 'bot running on your system, you're part of a problem and maybe something a little heavy-handed is warranted.
I think this is a good method. It's a lot harder to ignore than other ways that you've suggested (how much of an automated phone message would you listen to if it started as "This is a courtesy call from Comcast internet services..."). HTTP also a service that people are more likely to use every day, and there's little chance that an errant spam filter will block it.
A risk - in theory - is that when people see this popup, they'll say "I'm supposed to not interact with these things" and just click "Close," rather than understanding what it says. On the other hand, if your computer is infected with some sort of 'bot, you probably click through things like this anyway.
Which is a great thing. LEO is something that private companies can do (or are very near being able to do), so there's no reason to compete against them. So I'm good with the part about shifting that part of the responsibility away from NASA.
At the same time, I don't see where the exploration role fits in to this new plan. That's the part that concerns me.
Having said that, so far all of the things that we've heard have been leaks and conjecture. So it's probably not fair to condemn (or applaud) the plan until we've heard what it actually is.
In the earliest days of private air travel, one of the biggest and most reliable customers was the government - the US Postal Service. The government can create an initial market that allows private companies to be created and innovate to become cheaper and more reliable; that innovation creates makes the platform reliable and affordable, which encourages private market demand.
That's not to say that I support this decision. As stated by some other posters here, private (or publicly traded) companies aren't interested in the sort of exploration for exploration's sake that the government can do - they only "explore" if there is a known profit to be made. The problem with space exploration is that despite any evidence of great things sent back by robotic probes, there aren't really any clear avenues for profit in deep space missions. That doesn't mean that the opportunities aren't there, it just means that we don't know about them - the government can help us find them, and along the way the government can share what it learned with the nascent commercial spaceflight industry - to the benefit of all.
Or we can scrap it and hope for the best. America has already lost in the commercial satellite launch business; now we're on track to lose the rest - then what? We are one of two nations on this planet that have both the means and experience to create a great human spaceflight program. Are we going to throw that away?
On Friday, the panel released some details of the drinking allegations, but emphasized that they were anecdotal and had not been corroborated. [...]
At a news conference here Friday, the panel's chairman, Colonel Bachmann, said via telephone hookup that the reason the anecdotal references to the drinking incidents were included in the report that the panel delivered to NASA was not to suggest that the agency necessarily had an alcohol problem, but to emphasize the importance of heeding flight surgeons.
The panel did not ask for details of the accounts, including reports of heavy alcohol use by astronauts immediately before flights, and does not know how any such episodes were resolved, he said.
"In none of these can we say factually they did or did not occur," he continued, adding that the panel's mission had been not to investigate allegations but to point out that health and safety concerns might have been ignored.
Fair enough. I'm focusing on anecdotes mainly because on paper, it's easy to say something is "possible" or "impossible" or "unlikely" but in real life, especially given the subtle complexities of RF, we are often surprised by things that are "unlikely." I would start by pointing again to the graph here: http://www.imp-detail.org/images/gps.gif. What it's showing there is a stray harmonic from a GSM phone (1900MHz in this case... I'm looking for that particular paper, because it was a very good paper, but seem to have lost it. If I find it again I'll post a link here) that overlaps the GPS band. There's a similar story I mentioned regarding a post made to the FAA's Technical Exchange Record (TEX-TACR-04-3, 15 October 2004) where an 2.4GHz wireless camera was knocka mountaintop radar facility (ARSR) about 7.5 miles away offline - the camera was creating a -10dB harmonic in the L band (the facility operated in a window of around 980-1085MHz) that was enough to cause the radar to disregard all inputs as spurious.
In both of these cases, the result was a piece of equipment not functioning at all. What's more worrisome is something like a GPS, ILS, or VOR operating but being slightly wrong. This can happen for several reasons... when something goes wrong it can lead to an "HMI event" (Hazardously Misleading Information).
In a nutshell, a VOR works like this: VOR stations are ground-based transmitters in known locations which repeatedly broadcast 2 simultaneous signal pulses. The first signal is an omnidirectional reference containing the station's identity, and the second signal is swept rapidly (around 30 rps) through 360 degrees at such a rate that the signals are in phase at magnetic north and 180 degrees out of phase to the south. By measuring the phase angle between the two signals, aircraft listening to a VOR station can compute their radial (the compass angle formed by the direct vector to the VOR station and magnetic north) to no worse than 1.4 degrees. Aircraft location can be computed via angulation using two VOR stations.
The two broad classifications of interference that affect a VOR are known as type A and type B. Type A interference is associated with radiation at frequencies in the aeronautical radio navigation bands caused by intermodulation or other spurious emissions and other out of band radiation. Type B interference is associated with radiation originating at frequencies within other bands - this type of interference is caused by non-linearities in the ILS/VOR receiver and by desensitization. Type B interference is of note here because a pair of RF sources may cause intermodulation effects within the first stages of the aircraft's receivers (this has been an issue in FM radio stations broadcasting at the upper FM band, which ends just where the VOR's band begins. FM broadcast towers transmit with relatively high power outputs, but we can view that as a proof of concept, although given the proximity of the frequency ranges it's not necessarily a good one.)
Most consumer electronics such as cell phones or computers (laptop computers especially, since low size and weight requirements result in skimping on RF shielding) are both intentional radiators (i.e. 802.11b wireless devices) and unintentional radiators. In particular, most digital electronic devices today have internal clocks; repetitive digital signals such as these clocks are rich with harmonics that can extend well into the GHz range. The FCC regulations for unintentional radiators are intended to prevent interference with things like nearby television or broadcast radio receivers, but nothing more. FAA limits (for equipment installed on commercial aircraft) are around 1000 times lower than commercial limits.
External cables and shielding discontinuities are the most common sources for EMI, but secondary antennas, like internal cables or even traces on PC boards, can also contribute to emissi
You're right about this being extensively tested. Two colleagues of mine did a sizeable amount of this sort of testing. An 8' square shack mounted on a hoist, filled with racks and gear to where there was barely room for 2 people, incredibly long damn days being moved up/down/left/right outside of a stationary jet, bombarding the aircraft with all sorts of RF from every possible angle on an airfield in Arizona. Their tone when they talk about that project always brought to mind the last Death March coding project I endured.
Admittedly, I *don't* know which aircraft these two friends tested. But, what you referred to as 'front-door' risks were found, they can be reproduced in-cabin by a handheld HAM-license transceiver and they're capable of altering instrument readings enough to be devastating at times, including during landing. Frankly, the reason I don't know more is because they didn't *talk* about specifics here, in a way that mirrored how they didn't talk about specifics whenever they weren't allowed due to nondisclosure contracts or government classification. (Please, don't swerve into this side topic; I don't honestly know if any of this was classified or not). It's been extensively tested by several parties, including Boeing, the FCC, the FAA, and NASA, as well as several groups at universities affiliated with the IEEE. There have been no peer-reviewed tests concluding that it's impossible for PEDs to interfere with aircraft systems. On the contrary, there are demonstrated risks and identifiable pathways for interference and foreseeable consequences.
Because these friend of mine have. And they didn't walk away *SURE* that this sort of thing was impossible. They walked away knowing that interference was profoundly difficult, rare, had narrow frequencies that affected the specific plane... and possible. They had complete confidence that cellphone use wasn't likely to hit all those at once, but they didn't think it was technically feasible/possible to test all the scenarios to guarantee that a stray harmonic out of some personal device wasn't going to cause trouble. They both would routinely insist that they agreed with cellphones being turned off, since that incredibly thin chance still existed. Again, the ASRS reports (uninformed as bananaendian seems to think they are) back this up: there are occasions when PEDs interfere with avionics. In any of the examples I cited from the ASRS, there is a scenario where the ending could have been much less happy: a TCAS-directed climb into another aircraft, a landing in low-visibility conditions that misses a runway... the consequences are clear.
Yeah, I think uninformed nontechs are the bane of all science policy rhetoric in the world today. I take it you're referring to me, though (as an EE who has seen these very tests performed at the FAA) in fact I am actually informed on this topic. Thanks.
At some point, in-flight cellular might be allowed, and my nontech opinion is that a picocell helps because it'll dial back the adaptive transmitters in cell phones to minimize their ability to punch thru and cause problems. But I wager it'll be as restricted as smoking and laptops. Risk Management (which *is* my day job) is entirely about balancing the small inconvenience of turning off a few hundred RF emitters for twenty minutes at each end of a flight against the fiery, screamin' deaths of a couple hundred people. And risk management is what this is all about. But since this is a public arena, everyone can't choose their own level of risk: the FAA has to decide what level of risk is acceptable for everyone in this country, and set the limits accordingly. That's where the uncertainty becomes important. Do you want someone who is so sure of themselves to make those rules? I don't.
pompous and belligerent, eh? hey dude, this is slashdot!
Fair enough, I concede that point:)
Your FAA experience and ASRS represent the uninformed opinion here.
The ASRS reports represent actual experiences by actual pilots. Whether or not the pilots have degrees in engineering isn't relevant, if they're accurately reporting the conditions they've seen. That's the point of ASRS.
You dare question my opinion with that 'Implementation' garbage of yours? They are based on actual measurements with the Airforces Material Command electronics warfare cave as well as a throughout knowledge and experience of measuring and fixing board level avionics packages. My opinion is based on laws of physics - not on some speculation implied from some statistics.
The 'Implementation garbage' of which you speak creates an informed opinion. Perhaps you don't understand what my role was, but my opionions are based on actual measurements taken from actual PEDs on actual airplanes, not in some contrived testing environment. These measurements were also based on the laws of physics. The statistics are just backup.
It's very simple. Consumer electronics in modern commercial aircraft cabin aren't allowed to interfere with avionics. There's all kinds of internal structures between the passenger and the avionics bay and your silly diagrams of mobile phone signal going through the floor and into the antenna cable are just silly. It's silly because I've measured it and it doesn't work! It doesn't work because the antenna cables have been shielded and properly connected.
Oh, and will you arrest the laptop that doesn't comply with FCC Part 15 rules? The fact is that consumer devices aren't "allowed" to interfere with avionics, but sometimes they do anyway - because of design flaws, or because of equipment flaws. That's why unintentional radiators have to be taken into account in design.
My "silly" diagrams are meant to illustrate a point. The cabin floor of a commercial aircraft isn't a Faraday barrier that blocks all EMI from the passenger cabin. I don't know how your measurements were taken, but surely you agree that subtle changes, such as slightly different antenna cable lengths, can affect results. All of these things are tightly specified, but in "real life" nothing is perfect (not even your testing conditions).
Your reference to an anecdote of Piper Cherokee test flight having problems with GPS while the pilot used a mobile is just silly. What do you expect from a navigation system that was never ever meant or designed for flight critical navaid for aviation use! And that stupid Cherokee isn't exactly a commercial jet. It probably had a Garmin 430 with a RG-58 antenna cable to the top of the cabin with poor connections. Of course the GPS signal is going to be blocked by interference. But as you and me know very well, that is exactly the reason why planes like Cherokee's aren't certified for precision landing using GPS. I challenge you to go and do the same in a 737 using Collins GPS unit and with antenna cables installed by certified avionics technician and tested for external emissions hardness. Good luck with that one.
The anectdotal reference of the Piper Cherokee test flight was meant to point out the fact that GPS (for example) using a different set of frequencies than cell phones doesn't mean that cell phones are not capable of interfering with GPS. You're correct that the navigational systems on a Piper Cherokee are vastly different than those on a 737. However, even in a modern, well-designed aircraft, there are places for stray signals to enter the system. FAA requirements state that avionics systems with catastrophic or hazardous failure modes have to be "immune" to back-door coupling, but a) nothing is perfect, and b) less critical systems do not share this requirement.
The post that bananaendian references here, while pompous and belligerent, appears to represent an opinion rather than informed fact. The final shot of that post, "I'm an avionics technician and I teach this stuff. I'm also radio amateur and electronics warfare instructor so I kind of work with RF on a daily basis," doesn't necessarily prove that the poster has a solid understanding of these particular issues. FWIW, I spent two years working for the FAA with the NAVAIDS we're discussing here. If you really are familiar with electronic warfare, you have no doubt that it's trivial to totally hose the avionics on a commercial aircraft. The posts I referenced above represent my personal experiences working for the FAA, as well as the personal experiences of commercial pilots as reported to NASA's ASRS (Aviation Safety Reporting System).
Regulatory actions by the FAA, like those in other federal agencies, are often held hostage to uninformed public opinion. So far they've held fast on this particular rule, and I hope that (if nothing else) it stays in place.
A voting system should have a trivially small margin of error. All it has to do is count! What sort of margin of error would you expect from your computer if you asked it to count to 10,000? 100,000? Think of programming a "for" loop:
for(int i=0; i<100000; i++) { // stuff }
If you told your computer to do this, and it only went through the loop 90,000 times, or if it went through the loop 110,000 times, or even 100,001 or 99,999 times, would that be acceptable? No - there's no good reason for a margin of error to exist there.
Counting is easy. Storing a count is easy. The only hard part in a voting machine should designing the user interface. If the user interface lets the user verify his or her results before submitting them, and try again until they get it right, there should be no source of error there either.
A measurable margin of error in counting is unacceptable, especially in a system where so much is at stake.
The biological model is an interesting parallel, but we should also look at the failings of the biological model -- within your body, you are still a big monoculture, so once whatever foreign matter is in, it won't encounter anything radically new.
Intrusion tolerance, IMO, is just a subset of fault tolerance -- something failed to let the intrusion happen. So how do you tolerate that sort of fault?
reduce interdependency and single points of failure. If everything relies on the firewall box, and the firewall box goes down, then everything is down, even if everything else wasn't compromised. This is a failing of the biological model -- there are lots of lines of defense, but what happens when something goes straight for the heart? The brain? The spleen? A fault-tolerant system can't have a single point of failure.
just say "no" to monoculture. This should be a given in redundancy and fault tolerance, but often isn't. So your firewall is a linux box, and it gets hacked, but that's OK because you have another firewall. Oh wait, it's a linux box too, so it will fail in the same manner. This is not good intrusion tolerance, because your intruder can duplicate his or her (or its) past actions -- more of the same probably won't even slow him/her/it down much.
spread stuff around. This usually happens anyway because of load balancing, but couple this with #2 (reducing monoculture) and you'll really slow down an attacker, especially if you can make the separations transparent from the outside.
be vigilant! There's no replacement for the human element; hire somebody (or a team of somebodies) to do nothing but spend all day logged in to critical machines and make sure that nothing out of the ordinary happens. This is another failing of many security models -- people think that they can replace people with machines, but machines are easy to fool -- well-trained people are harder to fool, and the combination of the two (since they are fooled in different ways, see #2) is a lot harder to get around.
A good fault-tolerant system will have multiple layers that fail in totally different ways. This will thwart most automated attacks, since they tend to exploit a single, known vulnerability and won't be equipped to respond to another, totally different layer. If the layers are different enough (say a *nix-based firewall behind a Windows-based firewall), most attackers will be so thrown off that they will (at the very least) have to spend a significant amount of time trying to figure out what to do next. This buys you time to realize what's going on and stop it. Couple this with a very low interdependence, and an attacker can spend a lot of time breaking in to something that may be of little or no use to them.
Intrusion tolerance? You betcha -- this acknowledges the fact that there's no such thing as failsafe security, but takes advantage of a wide variety of options, which won't fail similarly, to slow down attacks and give administrators time to see what's going on and stop it.
Isn't this all obvious though? It seems like it when you read it, but the 4 concepts noted above are very often ignored (to varying degrees). Especially #2; this is the hardest because it means hiring a *nix geek and a Windows geek and a Cisco geek and maybe a couple of other ones as well, and no one wants to spend that kind of money. So instead, they get a guy or gal who only knows one system, so everything lives or dies on the failings of that system. Or even worse, they hire a whole team of guys and/or gals that all agree to use the same platform, for simplicity's sake. Bad! Bad! Remember the scale:
More Secure...................Less Secure
_________________________________________
Less Convenient...........More Convenient
Honestly, I'd love to see anyone try and ssh anywhere with just ink for input!
...done. My experience with the MS HWR on my Fujitsu tablet has been contrary to what I've seen mentioned here so far -- it's actually pretty good. It took a week or so of "training" before it reliably picked up the sort of things that I write, but I can now use ssh (and the *nix CLI) using HWR quickly and reliably.
Where the HWR fails is its reliance on the dictionary -- which means that abbreviations or cryptic filenames won't come out right. But with a slight amount of patience, you can peck short things like that out on the keypad, which is OK with me. If your filenames or 'folder' names are words, then there's no reason to not use ink to fill them out.
As far as the graphical login goes, I prefer to not handwrite the password, because writing a password in "invisible ink" would be a bit hard for me, especially with mixed case and numbers and such.
There seems to be a knee-jerk reaction here that Tablet PCs are bad because they are being pushed by Microsoft. Really, despite what people think about Microsoft, the Tablet is a useful gadget if you don't think about it like a laptop.
As far as putting Linux on the tablet goes, I've looked in to it but so far I haven't seen any real advantages that would make the amount of work required worthwhile. Just my $.02
Perhaps you should be reminded that the department of agriculture (USDA) is responsible for the safety of our food and drinking water, among other things. One might also point out that the USDA was created by Abraham Lincoln, in 1862, to ensure a good supply of food for the country (basically the same mission it still has today).
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So: they don't have an e-mail address for you, or a phone number, and you throw out all postal mail you get from them. How do you suggest they contact you if there's a problem? I wouldn't be in favor of overuse of this method, but if you've got a 'bot running on your system, you're part of a problem and maybe something a little heavy-handed is warranted.
I think this is a good method. It's a lot harder to ignore than other ways that you've suggested (how much of an automated phone message would you listen to if it started as "This is a courtesy call from Comcast internet services ..."). HTTP also a service that people are more likely to use every day, and there's little chance that an errant spam filter will block it.
A risk - in theory - is that when people see this popup, they'll say "I'm supposed to not interact with these things" and just click "Close," rather than understanding what it says. On the other hand, if your computer is infected with some sort of 'bot, you probably click through things like this anyway.
Which is a great thing. LEO is something that private companies can do (or are very near being able to do), so there's no reason to compete against them. So I'm good with the part about shifting that part of the responsibility away from NASA.
At the same time, I don't see where the exploration role fits in to this new plan. That's the part that concerns me.
Having said that, so far all of the things that we've heard have been leaks and conjecture. So it's probably not fair to condemn (or applaud) the plan until we've heard what it actually is.
In the earliest days of private air travel, one of the biggest and most reliable customers was the government - the US Postal Service. The government can create an initial market that allows private companies to be created and innovate to become cheaper and more reliable; that innovation creates makes the platform reliable and affordable, which encourages private market demand.
That's not to say that I support this decision. As stated by some other posters here, private (or publicly traded) companies aren't interested in the sort of exploration for exploration's sake that the government can do - they only "explore" if there is a known profit to be made. The problem with space exploration is that despite any evidence of great things sent back by robotic probes, there aren't really any clear avenues for profit in deep space missions. That doesn't mean that the opportunities aren't there, it just means that we don't know about them - the government can help us find them, and along the way the government can share what it learned with the nascent commercial spaceflight industry - to the benefit of all.
Or we can scrap it and hope for the best. America has already lost in the commercial satellite launch business; now we're on track to lose the rest - then what? We are one of two nations on this planet that have both the means and experience to create a great human spaceflight program. Are we going to throw that away?
Maybe it's worth waiting to see if this is actually a problem before we start calling it that? Just a thought
Fair enough. I'm focusing on anecdotes mainly because on paper, it's easy to say something is "possible" or "impossible" or "unlikely" but in real life, especially given the subtle complexities of RF, we are often surprised by things that are "unlikely." I would start by pointing again to the graph here: http://www.imp-detail.org/images/gps.gif. What it's showing there is a stray harmonic from a GSM phone (1900MHz in this case ... I'm looking for that particular paper, because it was a very good paper, but seem to have lost it. If I find it again I'll post a link here) that overlaps the GPS band. There's a similar story I mentioned regarding a post made to the FAA's Technical Exchange Record (TEX-TACR-04-3, 15 October 2004) where an 2.4GHz wireless camera was knocka mountaintop radar facility (ARSR) about 7.5 miles away offline - the camera was creating a -10dB harmonic in the L band (the facility operated in a window of around 980-1085MHz) that was enough to cause the radar to disregard all inputs as spurious.
... when something goes wrong it can lead to an "HMI event" (Hazardously Misleading Information).
In both of these cases, the result was a piece of equipment not functioning at all. What's more worrisome is something like a GPS, ILS, or VOR operating but being slightly wrong. This can happen for several reasons
In a nutshell, a VOR works like this: VOR stations are ground-based transmitters in known locations which repeatedly broadcast 2 simultaneous signal pulses. The first signal is an omnidirectional reference containing the station's identity, and the second signal is swept rapidly (around 30 rps) through 360 degrees at such a rate that the signals are in phase at magnetic north and 180 degrees out of phase to the south. By measuring the phase angle between the two signals, aircraft listening to a VOR station can compute their radial (the compass angle formed by the direct vector to the VOR station and magnetic north) to no worse than 1.4 degrees. Aircraft location can be computed via angulation using two VOR stations.
The two broad classifications of interference that affect a VOR are known as type A and type B. Type A interference is associated with radiation at frequencies in the aeronautical radio navigation bands caused by intermodulation or other spurious emissions and other out of band radiation. Type B interference is associated with radiation originating at frequencies within other bands - this type of interference is caused by non-linearities in the ILS/VOR receiver and by desensitization. Type B interference is of note here because a pair of RF sources may cause intermodulation effects within the first stages of the aircraft's receivers (this has been an issue in FM radio stations broadcasting at the upper FM band, which ends just where the VOR's band begins. FM broadcast towers transmit with relatively high power outputs, but we can view that as a proof of concept, although given the proximity of the frequency ranges it's not necessarily a good one.)
Most consumer electronics such as cell phones or computers (laptop computers especially, since low size and weight requirements result in skimping on RF shielding) are both intentional radiators (i.e. 802.11b wireless devices) and unintentional radiators. In particular, most digital electronic devices today have internal clocks; repetitive digital signals such as these clocks are rich with harmonics that can extend well into the GHz range. The FCC regulations for unintentional radiators are intended to prevent interference with things like nearby television or broadcast radio receivers, but nothing more. FAA limits (for equipment installed on commercial aircraft) are around 1000 times lower than commercial limits.
External cables and shielding discontinuities are the most common sources for EMI, but secondary antennas, like internal cables or even traces on PC boards, can also contribute to emissi
Admittedly, I *don't* know which aircraft these two friends tested. But, what you referred to as 'front-door' risks were found, they can be reproduced in-cabin by a handheld HAM-license transceiver and they're capable of altering instrument readings enough to be devastating at times, including during landing. Frankly, the reason I don't know more is because they didn't *talk* about specifics here, in a way that mirrored how they didn't talk about specifics whenever they weren't allowed due to nondisclosure contracts or government classification. (Please, don't swerve into this side topic; I don't honestly know if any of this was classified or not). It's been extensively tested by several parties, including Boeing, the FCC, the FAA, and NASA, as well as several groups at universities affiliated with the IEEE. There have been no peer-reviewed tests concluding that it's impossible for PEDs to interfere with aircraft systems. On the contrary, there are demonstrated risks and identifiable pathways for interference and foreseeable consequences. Because these friend of mine have. And they didn't walk away *SURE* that this sort of thing was impossible. They walked away knowing that interference was profoundly difficult, rare, had narrow frequencies that affected the specific plane... and possible. They had complete confidence that cellphone use wasn't likely to hit all those at once, but they didn't think it was technically feasible/possible to test all the scenarios to guarantee that a stray harmonic out of some personal device wasn't going to cause trouble. They both would routinely insist that they agreed with cellphones being turned off, since that incredibly thin chance still existed. Again, the ASRS reports (uninformed as bananaendian seems to think they are) back this up: there are occasions when PEDs interfere with avionics. In any of the examples I cited from the ASRS, there is a scenario where the ending could have been much less happy: a TCAS-directed climb into another aircraft, a landing in low-visibility conditions that misses a runway
pompous and belligerent, eh? hey dude, this is slashdot!
Fair enough, I concede that point :)
Your FAA experience and ASRS represent the uninformed opinion here.
The ASRS reports represent actual experiences by actual pilots. Whether or not the pilots have degrees in engineering isn't relevant, if they're accurately reporting the conditions they've seen. That's the point of ASRS.
You dare question my opinion with that 'Implementation' garbage of yours? They are based on actual measurements with the Airforces Material Command electronics warfare cave as well as a throughout knowledge and experience of measuring and fixing board level avionics packages. My opinion is based on laws of physics - not on some speculation implied from some statistics.
The 'Implementation garbage' of which you speak creates an informed opinion. Perhaps you don't understand what my role was, but my opionions are based on actual measurements taken from actual PEDs on actual airplanes, not in some contrived testing environment. These measurements were also based on the laws of physics. The statistics are just backup.
It's very simple. Consumer electronics in modern commercial aircraft cabin aren't allowed to interfere with avionics. There's all kinds of internal structures between the passenger and the avionics bay and your silly diagrams of mobile phone signal going through the floor and into the antenna cable are just silly. It's silly because I've measured it and it doesn't work! It doesn't work because the antenna cables have been shielded and properly connected.
Oh, and will you arrest the laptop that doesn't comply with FCC Part 15 rules? The fact is that consumer devices aren't "allowed" to interfere with avionics, but sometimes they do anyway - because of design flaws, or because of equipment flaws. That's why unintentional radiators have to be taken into account in design.
My "silly" diagrams are meant to illustrate a point. The cabin floor of a commercial aircraft isn't a Faraday barrier that blocks all EMI from the passenger cabin. I don't know how your measurements were taken, but surely you agree that subtle changes, such as slightly different antenna cable lengths, can affect results. All of these things are tightly specified, but in "real life" nothing is perfect (not even your testing conditions).
Your reference to an anecdote of Piper Cherokee test flight having problems with GPS while the pilot used a mobile is just silly. What do you expect from a navigation system that was never ever meant or designed for flight critical navaid for aviation use! And that stupid Cherokee isn't exactly a commercial jet. It probably had a Garmin 430 with a RG-58 antenna cable to the top of the cabin with poor connections. Of course the GPS signal is going to be blocked by interference. But as you and me know very well, that is exactly the reason why planes like Cherokee's aren't certified for precision landing using GPS. I challenge you to go and do the same in a 737 using Collins GPS unit and with antenna cables installed by certified avionics technician and tested for external emissions hardness. Good luck with that one.
The anectdotal reference of the Piper Cherokee test flight was meant to point out the fact that GPS (for example) using a different set of frequencies than cell phones doesn't mean that cell phones are not capable of interfering with GPS. You're correct that the navigational systems on a Piper Cherokee are vastly different than those on a 737. However, even in a modern, well-designed aircraft, there are places for stray signals to enter the system. FAA requirements state that avionics systems with catastrophic or hazardous failure modes have to be "immune" to back-door coupling, but a) nothing is perfect, and b) less critical systems do not share this requirement.
Actually, cellphones do endanger planes. So do other electronic devices. This is well document but generally ignored.
7 2
Here's my longer explanation for those interested:
http://www.imp-detail.org/archive.php?apid=107#10
http://www.imp-detail.org/archive.php?apid=112#11
The post that bananaendian references here, while pompous and belligerent, appears to represent an opinion rather than informed fact. The final shot of that post, "I'm an avionics technician and I teach this stuff. I'm also radio amateur and electronics warfare instructor so I kind of work with RF on a daily basis," doesn't necessarily prove that the poster has a solid understanding of these particular issues. FWIW, I spent two years working for the FAA with the NAVAIDS we're discussing here. If you really are familiar with electronic warfare, you have no doubt that it's trivial to totally hose the avionics on a commercial aircraft. The posts I referenced above represent my personal experiences working for the FAA, as well as the personal experiences of commercial pilots as reported to NASA's ASRS (Aviation Safety Reporting System).
Regulatory actions by the FAA, like those in other federal agencies, are often held hostage to uninformed public opinion. So far they've held fast on this particular rule, and I hope that (if nothing else) it stays in place.
If you told your computer to do this, and it only went through the loop 90,000 times, or if it went through the loop 110,000 times, or even 100,001 or 99,999 times, would that be acceptable? No - there's no good reason for a margin of error to exist there.
Counting is easy. Storing a count is easy. The only hard part in a voting machine should designing the user interface. If the user interface lets the user verify his or her results before submitting them, and try again until they get it right, there should be no source of error there either.
A measurable margin of error in counting is unacceptable, especially in a system where so much is at stake.
Intrusion tolerance, IMO, is just a subset of fault tolerance -- something failed to let the intrusion happen. So how do you tolerate that sort of fault?
A good fault-tolerant system will have multiple layers that fail in totally different ways. This will thwart most automated attacks, since they tend to exploit a single, known vulnerability and won't be equipped to respond to another, totally different layer. If the layers are different enough (say a *nix-based firewall behind a Windows-based firewall), most attackers will be so thrown off that they will (at the very least) have to spend a significant amount of time trying to figure out what to do next. This buys you time to realize what's going on and stop it. Couple this with a very low interdependence, and an attacker can spend a lot of time breaking in to something that may be of little or no use to them.
Intrusion tolerance? You betcha -- this acknowledges the fact that there's no such thing as failsafe security, but takes advantage of a wide variety of options, which won't fail similarly, to slow down attacks and give administrators time to see what's going on and stop it.
Isn't this all obvious though? It seems like it when you read it, but the 4 concepts noted above are very often ignored (to varying degrees). Especially #2; this is the hardest because it means hiring a *nix geek and a Windows geek and a Cisco geek and maybe a couple of other ones as well, and no one wants to spend that kind of money. So instead, they get a guy or gal who only knows one system, so everything lives or dies on the failings of that system. Or even worse, they hire a whole team of guys and/or gals that all agree to use the same platform, for simplicity's sake. Bad! Bad! Remember the scale:
More Secure...................Less Secure
_________________________________________
Less Convenient...........More Convenient
Eh. Talking's easy...
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eep
Honestly, I'd love to see anyone try and ssh anywhere with just ink for input!
...done. My experience with the MS HWR on my Fujitsu tablet has been contrary to what I've seen mentioned here so far -- it's actually pretty good. It took a week or so of "training" before it reliably picked up the sort of things that I write, but I can now use ssh (and the *nix CLI) using HWR quickly and reliably.
Where the HWR fails is its reliance on the dictionary -- which means that abbreviations or cryptic filenames won't come out right. But with a slight amount of patience, you can peck short things like that out on the keypad, which is OK with me. If your filenames or 'folder' names are words, then there's no reason to not use ink to fill them out.
As far as the graphical login goes, I prefer to not handwrite the password, because writing a password in "invisible ink" would be a bit hard for me, especially with mixed case and numbers and such.
There seems to be a knee-jerk reaction here that Tablet PCs are bad because they are being pushed by Microsoft. Really, despite what people think about Microsoft, the Tablet is a useful gadget if you don't think about it like a laptop.
As far as putting Linux on the tablet goes, I've looked in to it but so far I haven't seen any real advantages that would make the amount of work required worthwhile. Just my $.02
Perhaps you should be reminded that the department of agriculture (USDA) is responsible for the safety of our food and drinking water, among other things. One might also point out that the USDA was created by Abraham Lincoln, in 1862, to ensure a good supply of food for the country (basically the same mission it still has today).