You are not mixing up amplitude and frequency, you are mixing up addition and multiplication. Add two signals of different frequencies together, and all you get are those two frequencies. This underlies the whole concept of Fourier transforms. (The set of sin's and cos's form a complete basis [for a finite time record] so that other functions can be represented as a sum of these.)
Multiply two signals, like with a mixer from Minicircuits, and you get the sum and difference frequencies. (Any nonlinear element can act as a low efficiency mixer to some extant.)
Consider though that 6-channel, 96kHz, 24-bit digital encoding
Why would I want to consider that? Humans cannot hear sounds at frequencies up to 45 kHz. No speaker or headphone driver can reproduce a signal with a dynamic range of 24 bits, and I don't believe that any microphone is that sensitive.
So, an analog device that cannot be built can record sounds that a human being cannot hear. So what?
Electronic noise is an unavoidable reality. More bits (including infinity, aka theoretical analog) gains you nothing if the signal you want is below the noise.
The point is not that 10 granny smith apples tied together with string form a more or less valuable network than 5 crays. The comparison is between different networks of the same thing but of different sizes. And it is about the value of the network itself, not what the networked things accomplish. There is an underlying assumption that the metric under consideration values the networking; it is irrelevant that one can always think of a task for which networking doesn't improve performance.
No, it doesn't. What you are talking about is not security by obscurity.
SSH is already pretty secure. Switching to a different port may add another layer to the security.
Security by obscurity means taking a manifestly and trivially insecure protocol and trying to obscure it, rather than secure it, like running it on a different port instead of switching to a secure protocol. Like say allowing all X connections to blast through you firewall and connect to any machine (xhosts +), but running X on port 9000.
You can improve security with obscurity, but you cannot create security solely by obscurity.
The GPL sets a maximum price for licensing GPLed software. That price is zero. That is different from charging for physical copies. You may charge whatever you can get away with for the copy. The license is free. That is why the GPL says:
You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
This is an essential part of the GPL. When you download a copy of the Linux kernel, you receive a license to copy, modify, and distribute the code of each kernel contributer. The cost for these licenses is zero, as required by the GPL. If the GPL did not require free licensing, then you might have to pay every contributer for the right to copy or modify the kernel.
This is one of SCO's problems. They are trying to charge license fees for the kernel even though they distributed it, in blatent violation of the section of the GPL quoted above.
"Let's say the two largest OS makers in the market are Microsoft and IBM. If Microsoft and IBM collude to fix the price of their operating systems in order to freeze out competition, that is price-fixing and it is illegal."
There are several points that make Linux under the GPL different.
First, the GPL sets a maximum price. This is different from setting a price. If two competitors agree to set a price, this is considered to be always anticompetitive. Setting a maximum price is different.
Second, the GPL is by its nature a vertical agreement (between producer and distributer) rather than a horizontal agreement (between producers or between distributers). The rules are different. Horizontal pricing agreements of any sort are pretty much illegal, however certain vertical pricing agreements must be proven to reduce consumer choice or increase consumer prices.
Wallace argued that the GPL was the kind of price fixing agreement that is per se illegal; in other words, the agreement is by its nature illegal because it can be assumed to have a deleterious effect on consumers. He was wrong. This left him having to prove that the GPL hurts consumers, which he cannot because it doesn't. Instead, he argued that he as a competitor was hurt; unfortunately for him, antitrust law protects competition, not competitors.
Strangely, the decision says that his employment ended when he "decided to quit IAC and go into business for himself, in breach of his employment contract." [emphasis added] I don't see how it can depend on his thoughts or intentions rather than his actions, but that is what it says.
"preventing people from deleting files on laptops under their control was not what the Computer Fraud and Abuse Act was intended for (note, in particular, that it makes reference to a networked computer)."
Agreed, but that does not describe the facts of the case.
When the files were deleted, the laptop was not properly under his control because he was allegedly no longer an employee when he did the deletion. The Computer Fraud and Abuse Act comes into play, according to the judge, because the secure deletion program was in some way "transmitted" onto the laptop before it was used to do the "damage".
"Apparently on that technical ground the court made, incredibly, a unanimous decision. I find that preposterous and worrying."
The most important thing to notice here is that this was not a final judgment. This was a ruling regarding an appeal to the case being dismissed. A case is only dismissed in this way if the plaintiff has no case even assuming that every disputed fact is in his favor. Dismissing the case is like saying, "You're so wrong, that even if you were right, you'd still be wrong." The ruling here just lets the case go forward. The guy could still be totally exonerated in the end.
You are missing a key fact. He allegedly breached his employment agreement. If true, he at that moment became an ex-employee with no rights (or obligations) to do anything with the laptop. Company policy would be relevant if he had performed his actions while he was an employee. However, if he was no longer an employee, he had no right to decide if any file should be deleted or not.
"I think there is a distinction between two different uses of DRM."
Let me rephrase your two categories, while trying to preserve the essential meaning.
First, DRM can be used to help stop people from breaking the law, e.g. by making copies beyond what is permitted by fair use.
Second, DRM can be used to restrict users from exercising rights that otherwise would be theirs by law, such as making fair use copies of copyrighted material or running a copy of a program that they have purchased.
Unfortunately, all existing DRM seems to fall into both categories or exclusively into the second category. Perhaps the wild-eyed idealists are the ones who are considering how DRM might in theory be used, rather than how it is used in practice.
"Why do iPods outsell alternatives that, by all reckonings, deliver more for less?"
Do they? I am certainly not an expert, but I was recently reading reviews and checking prices for iPod-like MP3 players. The highest praise for any device was "sounds as good as an iPod" or "almost as easy to use as an iPod." I expected to be able to get something for 50% or less of the price of an iPod, but instead prices were within 10-20% for similar devices. At best, the non-iPod offered things I don't want, like receiving FM or running on AA batteries. (I would have liked to get Ogg, though.) I started the search expecting to get something nice at a price much lower than that of an iPod, but ended up making a purchase from the Apple store.
if the sole criteria for deeming something an "addiction" is that you spend a lot of time doing it so much as to neglect other activities, then why not say *sleep* is addicting?
Because that is a silly definition of addiction. William S. Burroughs covered this somewhere in Naked Lunch. Something is addictive if that thing creates the feeling of need for more of the thing. Certain drugs are addictive, because users cannot stand being without them, while I, who never tried them, do not miss them.
Oxygen is not addictive because my body inherently needs oxygen. The need was not created by exposure to oxygen. Same for sleep.
Computer use addictive? Perhaps for some people surfing or hacking could become a psychological need. This is different from just wasting a lot of time on computers.
I have read Linus, and the GPL3 draft, and lots of posts here, and I have not been able to find any explanation for Linus's statements about private keys. No one has posted any quote from GPL3draft that justifies that claim.
Sure, people can make up ways of using keys and signing that would violate GPL3draft. But there is little reason anyone would ever make such arcane, useless modifications.
Imagine some crazy company embedding a public key in all their compiled programs so that their distro can only run programs they have compiled. This contradicts the spirit of every version of the GPL, and there is no reason not to forbid it. On the other hand, allow users to turn off this checking or let them run code they have compiled themselves (either by recompiling the kernel to change keys or by letting them "sign" binaries for their own machines), and you are in compliance with the GPL3draft. What is wrong with that?
There are a lot of people who are perfectly happy as long as their Linux software remains free-as-in-beer. I can see why they might object to such changes in the GPL, because they can imagine a circumstance in which it would make it harder for them to get software for no charge. For anyone who cares about bug fixing, recompiling, or modifying their software in whatever fashion, tweaking the GPL to preserve that ability is only a good thing.
"However, a large number of people wanted a standalone browser."
This sounds like a rewrite of history, although it may be part of the story.
More importantly, there was a set of Mozilla developers who were tired of working with a vast code base where each decision had to be made by a committee and was endlessly criticized by posers who never wrote a line of code. These developers decided to write a new browser front end on their own so they could have fun again coding and be accountable to no one.
Amazingly, the new front end became wildly popular, even though the logo and the name are completely different animals. (Foxes are cool, but red pandas a.k.a. firefoxes are cooler.)
The judge really botched the analysis of the DMCA argument. That is not likely to stand.
To quote, it requires that the cache exist "for the purpose of making the material available to users... who... request access to the material [from the originating site]." We understand what this is referring to - an ISP or a web proxy intercepts a web request and serves a cached copy of a page rather than getting a fresh copy. However, Google offers up its cached pages to people as an alternative to requesting the material from the originating site.
The judge's claim is that some people use the Google cache after unsuccessfully trying to load the original site (e.g. b/c of the slashdot effect). However, the user does not need to request the original page to load the page from the Google cache.
It seems clear that the law allows caching that is transparent to the user, while Google has gone to great pains to make their caching as untransparent as possible. On the other hand, this seems to have strengthened their fair use and estoppel claims.
As much as I despise all things Microsoft (see: hyperbole), Verdana is the font on my computers which is most readable at all sizes. Of course, all these computers run Linux.
I have looked through any number of different versions of Times and Helvetica. Some of them only look good at small sizes; some of them only look good at large sizes. Where they are bad, they are somewhere between highly annoying and utterly unreadable.
Of course, Verdana was designed specifically to work at all sizes on a computer screen by a real font genius (I recently read a nice piece about Matthew Carter, probably in the NYTimes). There are no hideous artifacts where the lines in the letters try to be 1.5 pixels wide and end up too fat or too thin, because Carter designed it to look right at each size. An amazing example of something that is simply done right.
"wrists get pounded by the Ctrl-Meta- combos all the time"
Kids, to help save your hands, remember that when doing a command like M-q (or even when typing an uppercase letter), hold down the modifier key with one hand and hit the letter with the other hand. IOW, for M-q, hold down the alt key on the right with your right hand, and hit the q with your left hand. This stops a lot of weird twisting of your wrist that is bad news.
"In AC, Actual power output is less because the current lags behind the voltage a bit."
Sort of. If the load is resistive, like a light bulb, the current and voltage will be almost in phase. They will be slightly (immeasurably?) off due to the inductance of the wires.
However, in some cases the voltage and current can be significantly out of phase. I believe one example is certain kinds of motor as they start up.
It is better to say that the volt-amps rating tells you how much current (not power) is going through your system. Drawing a lot of current will trip breakers, melt plugs, and so on regardless of whether the voltage and current are in phase (i.e. whether the delivered power is low or high).
"Which is why AC is used over braided wire, rather than solid conductor wire, making your point moot."
Not even close. The current in all the different wires interacts via the electric and magnetic fields, making the whole thing act about the same as a solid conductor. The skin depth at 60 Hz is about a cm, so any complications to the surface that are smaller than a cm are invisible to this effect. So it is true that rather than using a single conducter with a 10 cm^2 cross section, you would do better to have 10 conductors with a 1 cm^2 cross section as long as they were several cm apart.
The reason we don't use large solid core wires for much other than house wiring is that they are not happy being bent back and forth over time.
I think it arrogant to assume artificial electric fields cannot have an effect on their proper operation.
Of course it would be. That is why I explained things the way I did. There is a difference between saying "It has been proven that 60 Hz fields do not affect humans" and saying "There is no evidence that 60 Hz fields affect humans."
We can speculate all day about what could conceivably affect a human body, given the limits to our understanding. But that leads to tinfoil-hat country unless we look for some evidence in support. The fact is that no evidence shows that humans are hurt by 60 Hz EM fields.
Maybe some will appear tomorrow. Who knows? Certainly the study of how the body uses electrical signals is interesting, and maybe one day we will learn that a lot of the current accepted wisdom is wrong.
The question is whether the mere speculation that 60 Hz fields can harm people, with no supporting evidence, should cause us to condemn every house within a mile of a high voltage power line, install Faraday cages around every bed, and sue the power company over every case of cancer.
the "Skin Effect" really only becomes a concern at 1+ Megahertz
Not true. "For a conductor like copper, d=0.85 cm for frequencies of 60 cps." (Jackson) For individual wires, the skin depth is irrelevent at low frequency. On the other hand, when you are talking about massive cables or solid conductors for high power systems, that 8 mm matters.
Slashdot Mirror
Multiply two signals, like with a mixer from Minicircuits, and you get the sum and difference frequencies. (Any nonlinear element can act as a low efficiency mixer to some extant.)
No, you don't. I have tuned a guitar enough times to know.
What you get is that amplitude of the A pulsing (i.e. getting louder and softer) at a low rate.
This is math from like 9th grade. sin(f-df)+sin(f+df)=2sin(f)cos(df).
Why would I want to consider that? Humans cannot hear sounds at frequencies up to 45 kHz. No speaker or headphone driver can reproduce a signal with a dynamic range of 24 bits, and I don't believe that any microphone is that sensitive.
So, an analog device that cannot be built can record sounds that a human being cannot hear. So what?
Electronic noise is an unavoidable reality. More bits (including infinity, aka theoretical analog) gains you nothing if the signal you want is below the noise.
You don't get it.
The point is not that 10 granny smith apples tied together with string form a more or less valuable network than 5 crays. The comparison is between different networks of the same thing but of different sizes. And it is about the value of the network itself, not what the networked things accomplish. There is an underlying assumption that the metric under consideration values the networking; it is irrelevant that one can always think of a task for which networking doesn't improve performance.
No, it doesn't. What you are talking about is not security by obscurity.
SSH is already pretty secure. Switching to a different port may add another layer to the security.
Security by obscurity means taking a manifestly and trivially insecure protocol and trying to obscure it, rather than secure it, like running it on a different port instead of switching to a secure protocol. Like say allowing all X connections to blast through you firewall and connect to any machine (xhosts +), but running X on port 9000.
You can improve security with obscurity, but you cannot create security solely by obscurity.
Yes, it does.
The GPL sets a maximum price for licensing GPLed software. That price is zero. That is different from charging for physical copies. You may charge whatever you can get away with for the copy. The license is free. That is why the GPL says:
This is an essential part of the GPL. When you download a copy of the Linux kernel, you receive a license to copy, modify, and distribute the code of each kernel contributer. The cost for these licenses is zero, as required by the GPL. If the GPL did not require free licensing, then you might have to pay every contributer for the right to copy or modify the kernel.
This is one of SCO's problems. They are trying to charge license fees for the kernel even though they distributed it, in blatent violation of the section of the GPL quoted above.
Just to be clear, you can charge for a copy of a piece of GPLed software. You cannot charge for a license to use, copy, or distribute GPLed software.
There are several points that make Linux under the GPL different.
First, the GPL sets a maximum price. This is different from setting a price. If two competitors agree to set a price, this is considered to be always anticompetitive. Setting a maximum price is different.
Second, the GPL is by its nature a vertical agreement (between producer and distributer) rather than a horizontal agreement (between producers or between distributers). The rules are different. Horizontal pricing agreements of any sort are pretty much illegal, however certain vertical pricing agreements must be proven to reduce consumer choice or increase consumer prices.
Wallace argued that the GPL was the kind of price fixing agreement that is per se illegal; in other words, the agreement is by its nature illegal because it can be assumed to have a deleterious effect on consumers. He was wrong. This left him having to prove that the GPL hurts consumers, which he cannot because it doesn't. Instead, he argued that he as a competitor was hurt; unfortunately for him, antitrust law protects competition, not competitors.
Then why does the Ogg Vorbis FAQ say, "it is completely free, open, and unpatented"?
Why does the Flac FAQ describe it as an "open patent free codec"?
Please explain in what sense they are encumbered.
Strangely, the decision says that his employment ended when he "decided to quit IAC and go into business for himself, in breach of his employment contract." [emphasis added] I don't see how it can depend on his thoughts or intentions rather than his actions, but that is what it says.
Agreed, but that does not describe the facts of the case.
When the files were deleted, the laptop was not properly under his control because he was allegedly no longer an employee when he did the deletion. The Computer Fraud and Abuse Act comes into play, according to the judge, because the secure deletion program was in some way "transmitted" onto the laptop before it was used to do the "damage".
The most important thing to notice here is that this was not a final judgment. This was a ruling regarding an appeal to the case being dismissed. A case is only dismissed in this way if the plaintiff has no case even assuming that every disputed fact is in his favor. Dismissing the case is like saying, "You're so wrong, that even if you were right, you'd still be wrong." The ruling here just lets the case go forward. The guy could still be totally exonerated in the end.
You are missing a key fact. He allegedly breached his employment agreement. If true, he at that moment became an ex-employee with no rights (or obligations) to do anything with the laptop. Company policy would be relevant if he had performed his actions while he was an employee. However, if he was no longer an employee, he had no right to decide if any file should be deleted or not.
Let me rephrase your two categories, while trying to preserve the essential meaning.
First, DRM can be used to help stop people from breaking the law, e.g. by making copies beyond what is permitted by fair use.
Second, DRM can be used to restrict users from exercising rights that otherwise would be theirs by law, such as making fair use copies of copyrighted material or running a copy of a program that they have purchased.
Unfortunately, all existing DRM seems to fall into both categories or exclusively into the second category. Perhaps the wild-eyed idealists are the ones who are considering how DRM might in theory be used, rather than how it is used in practice.
Do they? I am certainly not an expert, but I was recently reading reviews and checking prices for iPod-like MP3 players. The highest praise for any device was "sounds as good as an iPod" or "almost as easy to use as an iPod." I expected to be able to get something for 50% or less of the price of an iPod, but instead prices were within 10-20% for similar devices. At best, the non-iPod offered things I don't want, like receiving FM or running on AA batteries. (I would have liked to get Ogg, though.) I started the search expecting to get something nice at a price much lower than that of an iPod, but ended up making a purchase from the Apple store.
Because that is a silly definition of addiction. William S. Burroughs covered this somewhere in Naked Lunch. Something is addictive if that thing creates the feeling of need for more of the thing. Certain drugs are addictive, because users cannot stand being without them, while I, who never tried them, do not miss them.
Oxygen is not addictive because my body inherently needs oxygen. The need was not created by exposure to oxygen. Same for sleep.
Computer use addictive? Perhaps for some people surfing or hacking could become a psychological need. This is different from just wasting a lot of time on computers.
I have read Linus, and the GPL3 draft, and lots of posts here, and I have not been able to find any explanation for Linus's statements about private keys. No one has posted any quote from GPL3draft that justifies that claim.
Sure, people can make up ways of using keys and signing that would violate GPL3draft. But there is little reason anyone would ever make such arcane, useless modifications.
Imagine some crazy company embedding a public key in all their compiled programs so that their distro can only run programs they have compiled. This contradicts the spirit of every version of the GPL, and there is no reason not to forbid it. On the other hand, allow users to turn off this checking or let them run code they have compiled themselves (either by recompiling the kernel to change keys or by letting them "sign" binaries for their own machines), and you are in compliance with the GPL3draft. What is wrong with that?
There are a lot of people who are perfectly happy as long as their Linux software remains free-as-in-beer. I can see why they might object to such changes in the GPL, because they can imagine a circumstance in which it would make it harder for them to get software for no charge. For anyone who cares about bug fixing, recompiling, or modifying their software in whatever fashion, tweaking the GPL to preserve that ability is only a good thing.
This sounds like a rewrite of history, although it may be part of the story.
More importantly, there was a set of Mozilla developers who were tired of working with a vast code base where each decision had to be made by a committee and was endlessly criticized by posers who never wrote a line of code. These developers decided to write a new browser front end on their own so they could have fun again coding and be accountable to no one.
Amazingly, the new front end became wildly popular, even though the logo and the name are completely different animals. (Foxes are cool, but red pandas a.k.a. firefoxes are cooler.)
To quote, it requires that the cache exist "for the purpose of making the material available to users... who... request access to the material [from the originating site]." We understand what this is referring to - an ISP or a web proxy intercepts a web request and serves a cached copy of a page rather than getting a fresh copy. However, Google offers up its cached pages to people as an alternative to requesting the material from the originating site.
The judge's claim is that some people use the Google cache after unsuccessfully trying to load the original site (e.g. b/c of the slashdot effect). However, the user does not need to request the original page to load the page from the Google cache.
It seems clear that the law allows caching that is transparent to the user, while Google has gone to great pains to make their caching as untransparent as possible. On the other hand, this seems to have strengthened their fair use and estoppel claims.
I have looked through any number of different versions of Times and Helvetica. Some of them only look good at small sizes; some of them only look good at large sizes. Where they are bad, they are somewhere between highly annoying and utterly unreadable.
Of course, Verdana was designed specifically to work at all sizes on a computer screen by a real font genius (I recently read a nice piece about Matthew Carter, probably in the NYTimes). There are no hideous artifacts where the lines in the letters try to be 1.5 pixels wide and end up too fat or too thin, because Carter designed it to look right at each size. An amazing example of something that is simply done right.
Kids, to help save your hands, remember that when doing a command like M-q (or even when typing an uppercase letter), hold down the modifier key with one hand and hit the letter with the other hand. IOW, for M-q, hold down the alt key on the right with your right hand, and hit the q with your left hand. This stops a lot of weird twisting of your wrist that is bad news.
Sort of. If the load is resistive, like a light bulb, the current and voltage will be almost in phase. They will be slightly (immeasurably?) off due to the inductance of the wires.
However, in some cases the voltage and current can be significantly out of phase. I believe one example is certain kinds of motor as they start up.
It is better to say that the volt-amps rating tells you how much current (not power) is going through your system. Drawing a lot of current will trip breakers, melt plugs, and so on regardless of whether the voltage and current are in phase (i.e. whether the delivered power is low or high).
Not even close. The current in all the different wires interacts via the electric and magnetic fields, making the whole thing act about the same as a solid conductor. The skin depth at 60 Hz is about a cm, so any complications to the surface that are smaller than a cm are invisible to this effect. So it is true that rather than using a single conducter with a 10 cm^2 cross section, you would do better to have 10 conductors with a 1 cm^2 cross section as long as they were several cm apart.
The reason we don't use large solid core wires for much other than house wiring is that they are not happy being bent back and forth over time.
Of course it would be. That is why I explained things the way I did. There is a difference between saying "It has been proven that 60 Hz fields do not affect humans" and saying "There is no evidence that 60 Hz fields affect humans."
We can speculate all day about what could conceivably affect a human body, given the limits to our understanding. But that leads to tinfoil-hat country unless we look for some evidence in support. The fact is that no evidence shows that humans are hurt by 60 Hz EM fields.
Maybe some will appear tomorrow. Who knows? Certainly the study of how the body uses electrical signals is interesting, and maybe one day we will learn that a lot of the current accepted wisdom is wrong.
The question is whether the mere speculation that 60 Hz fields can harm people, with no supporting evidence, should cause us to condemn every house within a mile of a high voltage power line, install Faraday cages around every bed, and sue the power company over every case of cancer.
Not true. "For a conductor like copper, d=0.85 cm for frequencies of 60 cps." (Jackson) For individual wires, the skin depth is irrelevent at low frequency. On the other hand, when you are talking about massive cables or solid conductors for high power systems, that 8 mm matters.