I'm not sure what you mean by modern quantum theory; I'm also not sure you have an accurate picture of my understanding of quantum mechanics.
It seems those papers tend to quote physicists on the philosophy of quantum mechanics, and a philosopher's understanding of the physics of quantum mechanics. Both of those tend to be weak. Also, it takes Penrose seriously, which should be a red flag.
Just let me say, for starters, that I believe the measurement problem is not a philosophical problem, but just a statement of our ability to prepare macroscopic systems in distinct quantum states. Read Gottfried's textbook for an explanation, in case you aren't up to speed.
I'm not sure what you find "highly dubious." I suppose it depends much on what you mean by "explainable" and "all aspects."
Consciousness is a pretty limited thing, in some sense. Take anesthesia, for instance; a bit of ether suspends consciousness pretty simply. If you take an overdose and die, its not at all clear that consciousness would return for any reason. Doesn't seem like anything supernatural or essentially quantum mechanical there.
Consider even the difference in consciousness before and after morning coffee.
On the other hand, if you argue that consciousness is some ineffable, inexplicably transcendental phenomenon, then you are assuming your way out of the more basic problem, and getting pretty close to assuming your conclusion.
If you try to apply quantum mechanics, you very quickly run into the limitations of needing a closed system to make any calculations. Do you really need the entire universe to be conscious? If so, how is it that so many people can apparently be conscious at the same time? Or are you a solipsist?
Note, of course, that consciousness is very different from memory, which does persist through a non-fatal anesthesia, but which is subject to its own fragility...now where did I leave my keys?
There isn't any kind of "figuring out" to be done. If the assumptions behind the calculation are correct, you'd have to find a different universe to live in.
That said, the limitation is far beyond what human engineering could conceivably exploit. The universe is freaking huge.
There are plenty of plain old engineering problems to be solved here on earth before we get within even an unbelievably tiny fraction of the problem posed by this theoretical calculation.
Your comment is on par with worrying that there are only 3 billion men/women to satisfy one's need for sex, and therefore needing to find a way to quickly double Earth's population. There are much smaller practical limits that are imposed by other constraints which could be modified. For example, by learning to dress properly.
I don't think your conclusion is correct; once you've supposed that there is some extension of the universe beyond the space-time assumed in this calculation, the conclusions no longer hold.
The original calculation was made using a particular geometry of space-time. Assuming a different geometry, such as a connection to such an extension, would result in a different calculation.
Furthermore, its not clear your definition of "wisdom" is congruent to the definition of "consciousness" which is postulated in the article.
Are you really so dense? What kind of definition are you using for accuracy? What you highlight are not restrictions on its accuracy, but rather its applicability to a specific problem: I've got a piece of organic material, and I want to know how old it is.
Dendochronology has a resolution of 1 year, over a range of over 1000 years. That's pretty damn accurate. What more do you want?
This is exactly analogous to the situation with physical standards. The national laboratories have very accurate standards for fundamental quantities, but they are hard to operate without trained personnel in elaborate facilities. So we use these very accurate standards to calibrate things like rulers and stopwatches which can be carried around and used by just about anyone.
Dendochronology is actually a very precise dating method. The basic idea is to match up tree rings one-to-one in an unbroken series, and count. There are scientific principles used to do the matching, and historical principles to include non-living samples in the temporal chain.
Its main drawback is typically a lack of wood with enough tree rings visible, a lack of dendochronological record for the region you are interested in, and the uncertainty of how long the source tree lived after it deposited its interior rings and before it was chopped down and and the final rings removed to make the artifact you have at hand. That's why you use the record that you have to calibrate a measurement system that has wider applicability.
Yeah, I'd have a hard time believing that, so, you know what? I read about all the things that happen in cells, and how people actually looked in microscopes and in nature and came up with experiments and did those experiments, and analyzed the results, and did more experiments, until they've put together reasonably plausible, testable, and scientific theories for cell biology, embryology, mutation, evolution, and so on, to explain how that can happen.
And in the meantime, Bible thumpers have done exactly squat to expose their beliefs to true critical analysis of any kind.
Well, before you worry yourself about that, perhaps you ought to think of other reasons that wood and/or stone and/or animal remains end up at high altitudes.
Such as humans building things on mountains and animals wandering around.
P.S. your asteroid theory would not even come close to working in the sense of causing a ship to wash up that high, and even less close to working in the sense of reproducing anything close to a Biblical narrative.
If I choose not to believe what is in the Bible, I still have science, which gets tested every day billions of times and keeps working.
Don't believe fluid dynamics? Planes keep taking off day after day. Don't believe quantum mechanics? Your CD player and DVD player keep reading disks using semiconductor laser diodes.
I've also got modern constitutional principles to explain that we, as citizens of our respective countries, can come up with reasonable rules for living with one another without killing people who choose to have silly beliefs that don't affect me.
I don't need to give some 2500 year old book of Hebrew just-so stories enormous importance in my philiosphical system to get by. I can use ideas that definitely came from humans, and seem to work, and when they don't work, they can be changed to fit new circumstances. That way, when new discoveries happen and make 2500 year old stories look sillier and sillier, I don't have to get my panties in a bunch; I can properly appreciate how people can understand the universe and each other better and better through hard work. That's called progress, and I like it. If you don't believe in human progress, perhaps you'd better turn your computer off and stop using the benefits of it. Your God of Abraham and Isaac and Jacob didn't give you the internet, science did. Now have some fucking respect.
There are also the morons and dopes who aim the cameras at the sun, causing images of the paper packing to be imprinted on the film. They then interpret the light leakage and letter images as some kind of divine message. Or, after the paper is ejected, they see "images" emanating from the sun.
Polaroid film is a complicated chemical and mechanical system, with crude optics in consumer-grade cameras. It is a technological wonder to be able to have a color photograph develop reasonably well in a user-friendly package with any kind of shelf life and color consistency. It should be easily understood that the process is delicate enough that it can be disturbed in any number of ways, and that a disturbance will typically reveal itself in a picture that differs from the actual scene that one tried to record.
Yet, particularly credulous people are willing to accept supernatural explanations for the malfunctions of a complicated technology stressed beyond its normal limits, rather than believe that the technology could malfunction. Sort of turns the nature of faith on its head, doesn't it?
Just as particularly credulous people will take a vaguely boat shaped object (my pet theory is a stone temple) in an inaccessible location as proof that the Noah story as told in the Hebrew scriptures is literally true, although that leads immediately to the most bizarre predictions in geology, anthropology, history, botany, zoology, and countless other fields of science, none of which are actually observed. They accept totally anything science-like that supports their preconceived notions, without accepting any burden at all of reasoning from these notions to all the additional scientific facts that would also be true in their version of reality.
Just to be clear, I certainly admit that Berners-Lee deserves his knighthood.
I didn't expect him to make predictions of Slashdot, of course. My point is that the "Web as we know it" today is a lot broader than anything Berners-Lee mentioned in his original proposal. No one person gave us "the World-Wide Web" in the sense that we mean it today: Amazon, Google, blogs, pop-ups, movie trailers, Flash animations,... Yes, he gave us the seed from which all those things grew. But did he know where it would lead? It would have taken an inhuman amount of foresight to do that.
It's very tricky to extrapolate back what people meant in an historical sense by *any* term in the past, even ones which are common today.
Removing ozone ONCE shifts the system away from equilibrium to favor products in the original reaction.
Changing the equilibrium by adding a high-rate reaction that uses ozone as a reactant (as occurs when CFC breakdown introduces Cl ions) does not result in the same amount of ozone; rather, the chemical equilibrium point is located at a lower ozone concentration.
You've simplified the model too much to capture the essentials of the atmospheric problem.
Given that you seem to know that the 2.4GHz band is already too crowded, I can't understand why you got a 2.4 GHz cordless phone when there are already perfectly good bands at 900 MHz for cordless phone usage.
Sure, I can understand the average consumer might get dazzled by the prospect of having more gigahertz than his neighbor's wimpy phone, but an above average slashdotter?
You could also hold out for a completely personalized telepathic link that would beam exactly the music you want to hear directly to your aural cortex on demand.
Or, you could choose to live in the real world, where we have intellectual property laws, for better or worse, and realize that DRM just ain't going away, and weak DRM is better for you than strong DRM.
As for iTunes, perhaps the customer wants music organized in a single location, with nifty features like Celebrity Playlists and a relatively sane browsing interface, without having to wade through whatever crap a random teenager thought would be great to share over P2P, regardless of actual sound/ripping quality, accuracy in labelling, musical quality, or server bandwidth. Or is that just me?
Let's see...Apple puts only what you call an ineffective lock on the music you download, yet this is the reason you haven't signed up for iTunes?
What, are you waiting for a store to come out with *effective* protection which gives you even less of what you want? "Federal take-it-up-the-@$$" protection?
Apple has to put some kind of protection on their downloads to reassure the labels. You claim that it is only a token effort. Isn't that the best you can hope for? Sounds like Apple is slying doing you a favor, as opposed to the draconian measures they could be taking.
Section 333 refers to "National bank obligations", roughly, paper money.
The idea behind the "fit to reissue" concept is that paper money (when the U.S. was on the gold standard) represented gold in some bank vault, and the bank printed only as many bills as it had gold. If you brought the bill back to the issuing bank, you could get the gold, if you wanted, or the bank could destroy the old bill and print a fresh one. Always preserving the link between paper money and the gold backing it.
If you alter the bill so that the bank can't tell anymore that it is valid, or can't tell how much the bill is worth, then you've broken the link. The risk is that the bank might be fooled into printing more paper money than it has gold to back it (OH MY GOD! THE GOLD STANDARD HAS COLLAPSED! RUN FOR YOUR LIVES!), or they will fail to replace a bill, meaning that there will not be as much paper money as gold. That is not a crime against the gold standard, but still causes a problem: if you run out of paper money, you have to use coins or barter, which are inconvenient, or wait for more gold to be dug out of the ground and end up in a bank vault somewhere.
Of course, none of this gold standard nonsense applies anymore, but it is still good to have laws to protect paper money.
Re:"set -e" will go a long way to helping you
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Fault Tolerant Shell
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· Score: 1
Well, the parent poster didn't do that, now, did he?
* His code *didn't* check the possible return codes, and would have become much more complicated if he had. That, and the called script would have had to collect and branch on all the outcomes of its constituents in order to determine which return code was appropriate.
* Most UNIX commands have a very limited, often undocumented, protocol of return codes (yet another example of the prevailing UNIX philosophy of keeping things simple rather than robust.) So it is hard to tell what happened beyond "worked" or "didn't."
* Capturing stderr is an even less robust technique; all sorts of UNIX utilities spew random stuff to stderr or the console whenever they feel like it. One needs to capture every important failure mode in a text search, and add yet more code to detect and select among all the possibilties. And don't forget the important information that ends up in log files or on the console as well.
There's no doubt that given enough time and effort one can make a script that is as bulletproof as one might like. But that is a far cry from "oh, just add one magic line to your script, and most of your problems are solved" which started this discussion.
Re:"set -e" will go a long way to helping you
on
Fault Tolerant Shell
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· Score: 1
Except, you have no real information as to what failure mode you encountered. You get a simple "pass/fail" result, with no preservation of the state at the point of failure.
Unless you partition your system's operations into tiny portions, each of which can only fail in one way, you don't know how to handle what went wrong.
You also left out the part where the handler wishes to try the underlying task again after waiting some appropriate time. Your simple wrapper then becomes a more complicated loop.
That is, you are suggesting to build, by hand, using shell scripting primitives, the functionality that a fault-tolerant error handling system attempts to provide.
Re:"set -e" will go a long way to helping you
on
Fault Tolerant Shell
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· Score: 1
Where did my definition equate destroying data with working?
The key thing, of course, is the definition of "working" you use, which depends on your unique requirements. If you think that exit() is a useful solution to a problem, you have a pretty easy problem to solve. Most useful software, however, has to provide a service; simply giving up because of something outside the client's control fails to provide the required service.
The answer to your question is that if you have to operate over an unreliable link you create a *protocol* that allows for retransmission of data, confirmation, etc., to create a robust, reliable virtual link over that unreliable link. You might queue transactions locally until the link is available, for instance.
"Work or die" is not the foundation of such a protocol. It is a symptom of the half-assed approach which is typical of UNIX hackers. Other symptoms include "use errno to signal failure," "everything should be a text file," and "use regular expressions to parse text files."
Re:"set -e" will go a long way to helping you
on
Fault Tolerant Shell
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· Score: 1
How does this get an "interesting" mod?
Scripts that simply die when they hit an error are not "fault tolerant" or "robust." They are simply par for the course in the UNIX universe, like regular expressions, which work great if everything is just right, and fail terribly when things change.
"Fault tolerant" systems KEEP WORKING in the presence of unexpected events. Emitting an error message and then leaving the user back at the command prompt is exactly the opposite.
This feature is a "little bit" like exceptions in the way that death is a "little bit" like a bump on the head. Real exceptions let you detect errors and then DEAL WITH THEM. They don't just prevent you from deadly accidents.
I think the reason the Hold state shows orange is so when you are pressing the buttons, but nothing works, you have this orange marker to remind you "hey, dummy, remember, you put it on hold so it wouldn't turn on in your briefcase." Otherwise, you start to think the thing is broken or out of battery (if powered off).
I understand your logic, but the real risk isn't that you press buttons while looking at the device; after all, if you are looking at the iPod, you'll see if the buttons get bumped.
The risk is buttons getting pressed when you aren't touching the iPod deliberately, particularly when it causes the device to power up and waste battery charge. You put it in hold to avoid this risk.
A 1992 textbook is not the way to understand what Planck was thinking in 1880--1910. Textbooks almost never give a true historical picture of the complicated ways in which ideas get formulated. The point of a textbook is to simplify; it took 30 years for QM to bubble up from the cauldron of statistical mechanics, and a textbook doesn't have time for a play-by-play, so it settles for a crude approximation.
Physicists are particularly prone to assuming that the mathematical derivation parallels the historical development. Planck absolutely did not have a flash of inspiration that oscillators take on discrete values; Einstein and Poincare get the credit for recognizing that oscillators get quantized. Read Planck's papers and you see he talks about continuous values for the oscillator energies. A truer picture of what happened is that Planck couldn't figure out any way ahead, so he finally took a look at Boltzmann's mathematical techniques although he philosophically disagreed with Boltzmann's approach.
Now we can see that the fact Boltzmann's approach WORKS means that the degrees of freedom of the EM field act according to quantum mechanics. That also explains the photoelectric effect (Einstein) and applying that same knowledge to atoms in solids explains the departure from the Dulong-Petit law at low temperature (Einstein again!). Planck had to catch up to Einstein in this thinking.
Einstein gets a bum rap for his position in the Bohr-Einstein debate. In fact, Einstein was the *dominant* figure in the emergence of QM. Take the specific heat of solids: Einstein had ONE experimental curve (diamond, I believe) that showed a disagreement with Dulong-Petit. BOOM, in something like the THIRD paper EVER written on quantum mechanics, Einstein explains it. Now that is totally ground-breaking.
Bohr was a hand-wavy kind of guy, and Einstein felt rightly that there was no justification at the time for believing quantum mechanics apart from statistical mechanics: Einstein knew that atomic spectra were measured with large numbers of atoms in a vapor, not individual atoms. So all you could say for certain is that the quantum rules explained what happens ON AVERAGE for atoms in a gas. Bohr jumped ahead to assuming that QM explained the individual atoms, not just an ensemble, and I think that is what set Einstein off.
Nowadays, we can do experiments on single atoms and single photons and see that quantum mechanics does work in that case, and Bohr turned out to be right. But that doesn't mean that Einstein was wrong, just that he wasn't convinced by Bohr's reasoning.
Slashdot Mirror
I'm not sure what you mean by modern quantum theory; I'm also not sure you have an accurate picture of my understanding of quantum mechanics.
It seems those papers tend to quote physicists on the philosophy of quantum mechanics, and a philosopher's understanding of the physics of quantum mechanics. Both of those tend to be weak.
Also, it takes Penrose seriously, which should be a red flag.
Just let me say, for starters, that I believe the measurement problem is not a philosophical problem, but just a statement of our ability to prepare macroscopic systems in distinct quantum states. Read Gottfried's textbook for an explanation, in case you aren't up to speed.
I'm not sure what you find "highly dubious." I suppose it depends much on what you mean by "explainable" and "all aspects."
Consciousness is a pretty limited thing, in some sense. Take anesthesia, for instance; a bit of ether suspends consciousness pretty simply. If you take an overdose and die, its not at all clear that consciousness would return for any reason. Doesn't seem like anything supernatural or essentially quantum mechanical there.
Consider even the difference in consciousness before and after morning coffee.
On the other hand, if you argue that consciousness is some ineffable, inexplicably transcendental phenomenon, then you are assuming your way out of the more basic problem, and getting pretty close to assuming your conclusion.
If you try to apply quantum mechanics, you very quickly run into the limitations of needing a closed system to make any calculations. Do you really need the entire universe to be conscious? If so, how is it that so many people can apparently be conscious at the same time? Or are you a solipsist?
Note, of course, that consciousness is very different from memory, which does persist through a non-fatal anesthesia, but which is subject to its own fragility...now where did I leave my keys?
There isn't any kind of "figuring out" to be done. If the assumptions behind the calculation are correct, you'd have to find a different universe to live in.
That said, the limitation is far beyond what human engineering could conceivably exploit. The universe is freaking huge.
There are plenty of plain old engineering problems to be solved here on earth before we get within even an unbelievably tiny fraction of the problem posed by this theoretical calculation.
Your comment is on par with worrying that there are only 3 billion men/women to satisfy one's need for sex, and therefore needing to find a way to quickly double Earth's population. There are much smaller practical limits that are imposed by other constraints which could be modified. For example, by learning to dress properly.
I don't think your conclusion is correct; once you've supposed that there is some extension of the universe beyond the space-time assumed in this calculation, the conclusions no longer hold.
The original calculation was made using a particular geometry of space-time. Assuming a different geometry, such as a connection to such an extension, would result in a different calculation.
Furthermore, its not clear your definition of "wisdom" is congruent to the definition of "consciousness" which is postulated in the article.
Are you really so dense? What kind of definition are you using for accuracy? What you highlight are not restrictions on its accuracy, but rather its applicability to a specific problem: I've got a piece of organic material, and I want to know how old it is.
Dendochronology has a resolution of 1 year, over a range of over 1000 years. That's pretty damn accurate. What more do you want?
This is exactly analogous to the situation with physical standards. The national laboratories have very accurate standards for fundamental quantities, but they are hard to operate without trained personnel in elaborate facilities. So we use these very accurate standards to calibrate things like rulers and stopwatches which can be carried around and used by just about anyone.
Dendochronology is actually a very precise dating method. The basic idea is to match up tree rings one-to-one in an unbroken series, and count. There are scientific principles used to do the matching, and historical principles to include non-living samples in the temporal chain.
Its main drawback is typically a lack of wood with enough tree rings visible, a lack of dendochronological record for the region you are interested in, and the uncertainty of how long the source tree lived after it deposited its interior rings and before it was chopped down and and the final rings removed to make the artifact you have at hand. That's why you use the record that you have to calibrate a measurement system that has wider applicability.
Yeah, I'd have a hard time believing that, so, you know what? I read about all the things that happen in cells, and how people actually looked in microscopes and in nature and came up with experiments and did those experiments, and analyzed the results, and did more experiments, until they've put together reasonably plausible, testable, and scientific theories for cell biology, embryology, mutation, evolution, and so on, to explain how that can happen.
And in the meantime, Bible thumpers have done exactly squat to expose their beliefs to true critical analysis of any kind.
Guess which one gets more credibility?
Well, before you worry yourself about that, perhaps you ought to think of other reasons that wood and/or stone and/or animal remains end up at high altitudes.
Such as humans building things on mountains and animals wandering around.
P.S. your asteroid theory would not even come close to working in the sense of causing a ship to wash up that high, and even less close to working in the sense of reproducing anything close to a Biblical narrative.
If I choose not to believe what is in the Bible, I still have science, which gets tested every day billions of times and keeps working.
Don't believe fluid dynamics? Planes keep taking off day after day. Don't believe quantum mechanics? Your CD player and DVD player keep reading disks using semiconductor laser diodes.
I've also got modern constitutional principles to explain that we, as citizens of our respective countries, can come up with reasonable rules for living with one another without killing people who choose to have silly beliefs that don't affect me.
I don't need to give some 2500 year old book of Hebrew just-so stories enormous importance in my philiosphical system to get by. I can use ideas that definitely came from humans, and seem to work, and when they don't work, they can be changed to fit new circumstances. That way, when new discoveries happen and make 2500 year old stories look sillier and sillier, I don't have to get my panties in a bunch; I can properly appreciate how people can understand the universe and each other better and better through hard work. That's called progress, and I like it. If you don't believe in human progress, perhaps you'd better turn your computer off and stop using the benefits of it. Your God of Abraham and Isaac and Jacob didn't give you the internet, science did. Now have some fucking respect.
Polaroid cameras can also be used to produce misleading images.
such as so-called "auras"
and Kirlian images.
There are also the morons and dopes who aim the cameras at the sun, causing images of the paper packing to be imprinted on the film. They then interpret the light leakage and letter images as some kind of divine message. Or, after the paper is ejected, they see "images" emanating from the sun.
Polaroid film is a complicated chemical and mechanical system, with crude optics in consumer-grade cameras. It is a technological wonder to be able to have a color photograph develop reasonably well in a user-friendly package with any kind of shelf life and color consistency. It should be easily understood that the process is delicate enough that it can be disturbed in any number of ways, and that a disturbance will typically reveal itself in a picture that differs from the actual scene that one tried to record.
Yet, particularly credulous people are willing to accept supernatural explanations for the malfunctions of a complicated technology stressed beyond its normal limits, rather than believe that the technology could malfunction. Sort of turns the nature of faith on its head, doesn't it?
Just as particularly credulous people will take a vaguely boat shaped object (my pet theory is a stone temple) in an inaccessible location as proof that the Noah story as told in the Hebrew scriptures is literally true, although that leads immediately to the most bizarre predictions in geology, anthropology, history, botany, zoology, and countless other fields of science, none of which are actually observed. They accept totally anything science-like that supports their preconceived notions, without accepting any burden at all of reasoning from these notions to all the additional scientific facts that would also be true in their version of reality.
Just to be clear, I certainly admit that Berners-Lee deserves his knighthood.
... Yes, he gave us the seed from which all those things grew. But did he know where it would lead? It would have taken an inhuman amount of foresight to do that.
I didn't expect him to make predictions of Slashdot, of course. My point is that the "Web as we know it" today is a lot broader than anything Berners-Lee mentioned in his original proposal. No one person gave us "the World-Wide Web" in the sense that we mean it today: Amazon, Google, blogs, pop-ups, movie trailers, Flash animations,
It's very tricky to extrapolate back what people meant in an historical sense by *any* term in the past, even ones which are common today.
Actually, the most interesting thing is that the original proposal by Berners-Lee offers no hint of commercial applications.
E-commerce, or even advertising-based commercial sites like Slashdot, don't get any mention at all.
Removing ozone ONCE shifts the system away from equilibrium to favor products in the original reaction.
Changing the equilibrium by adding a high-rate reaction that uses ozone as a reactant (as occurs when CFC breakdown introduces Cl ions) does not result in the same amount of ozone; rather, the chemical equilibrium point is located at a lower ozone concentration.
You've simplified the model too much to capture the essentials of the atmospheric problem.
Given that you seem to know that the 2.4GHz band is already too crowded, I can't understand why you got a 2.4 GHz cordless phone when there are already perfectly good bands at 900 MHz for cordless phone usage.
Sure, I can understand the average consumer might get dazzled by the prospect of having more gigahertz than his neighbor's wimpy phone, but an above average slashdotter?
Do you wear eyeglasses?
This is probably a side-effect of your choice of light-weight polycarbonate, which has a higher chromatic dispersion than glass.
You could also hold out for a completely personalized telepathic link that would beam exactly the music you want to hear directly to your aural cortex on demand.
Or, you could choose to live in the real world, where we have intellectual property laws, for better or worse, and realize that DRM just ain't going away, and weak DRM is better for you than strong DRM.
As for iTunes, perhaps the customer wants music organized in a single location, with nifty features like Celebrity Playlists and a relatively sane browsing interface, without having to wade through whatever crap a random teenager thought would be great to share over P2P, regardless of actual sound/ripping quality, accuracy in labelling, musical quality, or server bandwidth. Or is that just me?
As simple as possible...but no simpler!
It has to still fit the inconvenient experimental facts.
Let's see...Apple puts only what you call an ineffective lock on the music you download, yet this is the reason you haven't signed up for iTunes?
What, are you waiting for a store to come out with *effective* protection which gives you even less of what you want? "Federal take-it-up-the-@$$" protection?
Apple has to put some kind of protection on their downloads to reassure the labels. You claim that it is only a token effort. Isn't that the best you can hope for? Sounds like Apple is slying doing you a favor, as opposed to the draconian measures they could be taking.
Section 333 refers to "National bank obligations", roughly, paper money.
The idea behind the "fit to reissue" concept is that paper money (when the U.S. was on the gold standard) represented gold in some bank vault, and the bank printed only as many bills as it had gold. If you brought the bill back to the issuing bank, you could get the gold, if you wanted, or the bank could destroy the old bill and print a fresh one. Always preserving the link between paper money and the gold backing it.
If you alter the bill so that the bank can't tell anymore that it is valid, or can't tell how much the bill is worth, then you've broken the link. The risk is that the bank might be fooled into printing more paper money than it has gold to back it (OH MY GOD! THE GOLD STANDARD HAS COLLAPSED! RUN FOR YOUR LIVES!), or they will fail to replace a bill, meaning that there will not be as much paper money as gold. That is not a crime against the gold standard, but still causes a problem: if you run out of paper money, you have to use coins or barter, which are inconvenient, or wait for more gold to be dug out of the ground and end up in a bank vault somewhere.
Of course, none of this gold standard nonsense applies anymore, but it is still good to have laws to protect paper money.
Well, the parent poster didn't do that, now, did he?
* His code *didn't* check the possible return codes, and would have become much more complicated if he had. That, and the called script would have had to collect and branch on all the outcomes of its constituents in order to determine which return code was appropriate.
* Most UNIX commands have a very limited, often undocumented, protocol of return codes (yet another example of the prevailing UNIX philosophy of keeping things simple rather than robust.) So it is hard to tell what happened beyond "worked" or "didn't."
* Capturing stderr is an even less robust technique; all sorts of UNIX utilities spew random stuff to stderr or the console whenever they feel like it. One needs to capture every important failure mode in a text search, and add yet more code to detect and select among all the possibilties. And don't forget the important information that ends up in log files or on the console as well.
There's no doubt that given enough time and effort one can make a script that is as bulletproof as one might like. But that is a far cry from "oh, just add one magic line to your script, and most of your problems are solved" which started this discussion.
Except, you have no real information as to what failure mode you encountered. You get a simple "pass/fail" result, with no preservation of the state at the point of failure.
Unless you partition your system's operations into tiny portions, each of which can only fail in one way, you don't know how to handle what went wrong.
You also left out the part where the handler wishes to try the underlying task again after waiting some appropriate time. Your simple wrapper then becomes a more complicated loop.
That is, you are suggesting to build, by hand, using shell scripting primitives, the functionality that a fault-tolerant error handling system attempts to provide.
Where did my definition equate destroying data with working?
The key thing, of course, is the definition of "working" you use, which depends on your unique requirements. If you think that exit() is a useful solution to a problem, you have a pretty easy problem to solve. Most useful software, however, has to provide a service; simply giving up because of something outside the client's control fails to provide the required service.
The answer to your question is that if you have to operate over an unreliable link you create a *protocol* that allows for retransmission of data, confirmation, etc., to create a robust, reliable virtual link over that unreliable link. You might queue transactions locally until the link is available, for instance.
"Work or die" is not the foundation of such a protocol. It is a symptom of the half-assed approach which is typical of UNIX hackers. Other symptoms include "use errno to signal failure," "everything should be a text file," and "use regular expressions to parse text files."
How does this get an "interesting" mod?
Scripts that simply die when they hit an error are not "fault tolerant" or "robust." They are simply par for the course in the UNIX universe, like regular expressions, which work great if everything is just right, and fail terribly when things change.
"Fault tolerant" systems KEEP WORKING in the presence of unexpected events. Emitting an error message and then leaving the user back at the command prompt is exactly the opposite.
This feature is a "little bit" like exceptions in the way that death is a "little bit" like a bump on the head. Real exceptions let you detect errors and then DEAL WITH THEM. They don't just prevent you from deadly accidents.
I think the reason the Hold state shows orange is so when you are pressing the buttons, but nothing works, you have this orange marker to remind you "hey, dummy, remember, you put it on hold so it wouldn't turn on in your briefcase." Otherwise, you start to think the thing is broken or out of battery (if powered off).
I understand your logic, but the real risk isn't that you press buttons while looking at the device; after all, if you are looking at the iPod, you'll see if the buttons get bumped.
The risk is buttons getting pressed when you aren't touching the iPod deliberately, particularly when it causes the device to power up and waste battery charge. You put it in hold to avoid this risk.
A 1992 textbook is not the way to understand what Planck was thinking in 1880--1910. Textbooks almost never give a true historical picture of the complicated ways in which ideas get formulated. The point of a textbook is to simplify; it took 30 years for QM to bubble up from the cauldron of statistical mechanics, and a textbook doesn't have time for a play-by-play, so it settles for a crude approximation.
Physicists are particularly prone to assuming that the mathematical derivation parallels the historical development. Planck absolutely did not have a flash of inspiration that oscillators take on discrete values; Einstein and Poincare get the credit for recognizing that oscillators get quantized. Read Planck's papers and you see he talks about continuous values for the oscillator energies. A truer picture of what happened is that Planck couldn't figure out any way ahead, so he finally took a look at Boltzmann's mathematical techniques although he philosophically disagreed with Boltzmann's approach.
Now we can see that the fact Boltzmann's approach WORKS means that the degrees of freedom of the EM field act according to quantum mechanics. That also explains the photoelectric effect (Einstein) and applying that same knowledge to atoms in solids explains the departure from the Dulong-Petit law at low temperature (Einstein again!). Planck had to catch up to Einstein in this thinking.
Einstein gets a bum rap for his position in the Bohr-Einstein debate. In fact, Einstein was the *dominant* figure in the emergence of QM. Take the specific heat of solids: Einstein had ONE experimental curve (diamond, I believe) that showed a disagreement with Dulong-Petit. BOOM, in something like the THIRD paper EVER written on quantum mechanics, Einstein explains it. Now that is totally ground-breaking.
Bohr was a hand-wavy kind of guy, and Einstein felt rightly that there was no justification at the time for believing quantum mechanics apart from statistical mechanics: Einstein knew that atomic spectra were measured with large numbers of atoms in a vapor, not individual atoms. So all you could say for certain is that the quantum rules explained what happens ON AVERAGE for atoms in a gas. Bohr jumped ahead to assuming that QM explained the individual atoms, not just an ensemble, and I think that is what set Einstein off.
Nowadays, we can do experiments on single atoms and single photons and see that quantum mechanics does work in that case, and Bohr turned out to be right. But that doesn't mean that Einstein was wrong, just that he wasn't convinced by Bohr's reasoning.