Thus the emitted photon must be exactly in-phase with the incident photon, and is therefore fully coherent with the incident photon.
This is true, but does not explain the mass coherence of laser light. It cannot explain why only a single phase becomes prevalent. Remember the principle of superposition -- if laser action depended solely on the in-phase emission of radiation, that would not preclude the simultaneous existence of a great number of different phases. The number of phases would only be limited by the number of radiators available in the lasing medium.
It is, in fact, the mirrors which cause the light to become coherent en masse as opposed to being a mixture of phases. This is for the same reason that starlight is coherent, even though it was not so when it was emitted -- it has travelled a very large distance.
As I've already posted below, this is a fairly good explanation in simple terms.
The idea that laser light is coherent because of the in-phase emission of radiation is a misconception which has unfortunately been so widely disseminated that even some physicists believe it. It is a symptom of an education system based on rote memorization instead of critical thinking.
That would mean the color of the light should shift towards red every time it bounces off a mirror. I'm sure you are refering to intensity though.
No, you are neglecting the other way that energy can be lost -- some of the photons are absorbed when they strike the mirror. By "light" I meant the entire assemblage of photons, not individual ones.
Several people have now pointed this out. Maybe SF.net has changed their policies. But I'm fairly certain that a year and a half ago when I was investigating hosting a project there that the restriction was in place.
Your idea seems to be that it's ok for you to take something someone else made, and have a monopoly, not only on your additions to the other person's work (which the LGPL allows), but the portions of the original you incorporated with them.
I don't look down the pipe that direction. To me, it's about being generous and not being hung-up about whether other people might benefit from something I've done. I honestly don't expect anything in return. For me, the mere fact that somebody else found my code useful enough to incorporate into a product is thanks enough.
Thus my prior comment about ideologies in Open Source. To me the most ideology-neutral thing to do is to just throw the code out there and not worry about who might use it in what way.
Then there's the practical problem the BSD license opens up by allowing embrace-and-extend, but let's not chase that rabbit.
I understand that argument, and it makes a bit of sense to me. It's just not important enough to change my choice of license.
The reason laser light is coherent is because it travels an enormous distance before being emitted. This gives the individuals waves time to become coherent. Normally, this "enormous distance" is implemented by having the light bounce back and forth between two mirrors a large number of times. However, every time the light hits a mirror you lose a bit of energy. So, if the cavity is short, you must have a higher gain in order to get the required energy, because the laser has to make more reflections in order to travel the required distance to become coherent.
I'm pretty sure that's what I said:
``Unfortunately, the BSD license is better at preserving your freedom to take away my freedoms than it is at preserving my freedom to see, modify and share.''
I don't follow. What freedom is being taken away from you? The ability to see somebody else's code? Why should you have a right to see code that somebody else wrote unless they want you to?
It's a myth that is not possible to profit of GPL'ed code.
Only if you ignore the fact that most software companies' business models are based on selling software, not support. It's easy to just say "Well, they need to change business models" but that's not even approaching realistic.
The one argument against BSD-style licenses that makes at least partial sense to me goes like this:
Microsoft takes a piece of BSD-licensed software. They "embrace and extend" this software, causing it to be incompatible with the original version. Then, by leveraging monopoly power, they get the rest of the software world to use their version, thereby making the open version obsolete.
However, that only really matters to you if you have an ego. Really, who cares if anybody uses your software? You wrote it to fulfill your own needs, and the fact that it's been co-opted into something else doesn't change the fact that it still meets your needs and will continue to do so.
How about a license that was OSI-conformant when admitted to SourceForge? That interpretation (or perhaps rewording) would solve the problem.
I don't think they'd do that -- the purpose behind the OSI-conformant requirement is to maintain an iron grip on the projects on SF.net. Allowing non-conforming projects to exist would invalidate the entire point of SF.net, which was to consolidate all OSS projects in one place where they can be controlled by the ideologues of the OSS movement.
It's a devilishly clever plan, really: authorize a bunch of less radical licenses, get tens of thousands of projects to move to SF.net, then rip the rug out from under everyone by forcing them to switch to the radical licenses, or risk losing their hosting. I wonder if this was planned all along...
That's fine, and I can refuse to certify theirs back. That doesn't change whether my license, or theirs, is open source.
True, but they can prevent you from hosting your project on SourceForge. SourceForge does not accept projects that don't use OSI-conforming licenses.
Stunts like the one we're discussing right now make it abundantly clear why relying on SourceForge to host the majority of OSS projects was a BAD idea. People come to rely on the services SF.net provides, but the OSI license requirement gives them a stranglehold over you.
The BSD license does not restrict your freedom to see code which was already in the open. It simply makes it possible for people to make their OWN modifications private.
You make it sound like the BSD license could be used to close a previous open piece of software. That's impossible. BSD license simply gives you more powerful rights over your own modifications to that software. Some people see that as a flaw, others (including myself) don't see what the big deal is about allowing other people to profit as long as it doesn't restrict our own rights to use the code we've written.
Though open-source may be great, why should I be *forced* to GPL my game code, which has little to do with LibSDL development?
The usual response to that is that if you aren't willing to play the OSS game, you aren't allowed to use OSS code.
I think it's a juvenile attitude. "I willfully don't profit off my stuff so nobody else should either."
Of course, people are free to license things as they wish. I just think it's elitist to redefine the meaning of Open Source on a whim so that people who choose to release their code without restriction are no longer creating "open source."
The LGPL is a good compromise between the GPL and BSD licenses, although it's a little too wordy for my tastes.
In order to host your project on SourceForge it must use an OSI-conforming license. If the list of OSI-conforming licenses is drastically reduced what will happen to all the projects on SourceForge which don't use the GPL or BSD licenses? Will they just be booted off the server? Forced to switch licenses?
My God man, where did I complain about usability? I just said that buttons which go "poof" do nothing to improve it. In fact, given your strict delineation between the responsiblities of the X server and the windowing environment, I'd think you of all people would see the stupidity of buttons which go "poof" being implemented in the freaking X server.
Usually I'm the one defending XML from ignorant trolls on Slashdot, but in this case, I'll agree with them. I do not think that we should be sending XML to our videocards.
It wouldn't be PDF getting sent directly to the video card either. PDF (or SVG) would serve as a close-to-the-metal format, but not actually run on the metal. Obviously it's translated into another form before actually going to the video card.
Do you really think that Quartz is literally sending PDF to the video card? PDF is just the standard vector format in their video drivers.
But, as usual, it's easier to call somebody a troll than actually debate something.
X is not a GUI, X is not responsible for usability.
Exactly. What this means is that the usability improvements need to happen in the WM layer, not the X layer. My point is that we don't need more garbage piled on to the X server. We need more effort directed at improving usability (again, that doesn't imply that it's not already usable, just that we should always strive to improve).
Now go back under your bridge and wait for the next Gnome or KDE post where you sound like less of an idiot with your tired complaints.
All organisms are genetically modified in one fashion or another. Humans have been selectively breeding crops for growth rate, productivity and so on for thousands of years.
Breeding does not MODIFY the genes. It just mixes them into new combinations. GMO on the other hand have NEW genes that never existed before. Take some basic genetics.
But that's beside the point I'm about to make. Imagine the following scenario:
Monsanto patents some new GMO, say, tomatoes. These tomatoes interbreed with "natural" tomatoes. Soon, the patented gene has spread to all tomatoes thoughout the world. Now, Monsanto has a stranglehold on tomatoes, since they have a patent on every tomato on earth. Monsanto can now demand ridiculous sums of money, or they'll start suing every farmer on earth into bankruptcy. Either that, or simply revoke the permission to grow tomatoes, starving millions.
GMO must not exist so long as there are patents on GMO.
While I agree in principle on the need for hardware acceleration of PDLs (page description languages), can we PLEASE not use PDF as the standard? PLEASE?
People have commented on OS X's "gumdrop" window controls, which look cute and friendly, but few seem to notice they're arranged like a traffic light, which is intuitive for most people. Red, yellow, and green circles--red closes the window, yellow minimizes, and green zooms.
Uh, how is that intuitive? The red light for closing the window might make sense. But yellow to minimize? A yellow light means "this light is about to turn red." So, by clicking the yellow light, what does that mean? That my window might close soon?
And green means "go." In the context of a computer application, "going" probably means using the app. What does maximizing a window have to do with "going" somewhere?
Don't flame me for being an Apple basher -- my Mini just shipped two days ago and I can hardly contain myself -- and I'm not trying to say that the red/yellow/green is counterintuitive, but I'm really not seeing the analogy to traffic lights.
Yet more pointless eye candy without any real usability advances.
Don't get me wrong -- I think X is "usable enough," but really, I don't think the moniker "next generation" is appropriate for anything but the most fundamental technological advances. Buttons that go "poof?" Is this seriously what we're concentrating our effort on?
This is extremely common. I remember the first time I noticed it, in a trailer for (I think) Pitch Black. They were using the music from Stargate.
My brother is actually in the film scoring business, and this is the normal state of affairs. Once the real score is finished they'll start using it. The music hasn't been "stolen," but fairly licensed.
Focusing on a product seems rather pointless if nobody wants to buy it. I still don't understand what's so corporate-speak about "consumer focus." Can you not grasp the meaning? I mean, we're not talking about synergizing our paradigms here...
Slashdot Mirror
This is true, but does not explain the mass coherence of laser light. It cannot explain why only a single phase becomes prevalent. Remember the principle of superposition -- if laser action depended solely on the in-phase emission of radiation, that would not preclude the simultaneous existence of a great number of different phases. The number of phases would only be limited by the number of radiators available in the lasing medium.
It is, in fact, the mirrors which cause the light to become coherent en masse as opposed to being a mixture of phases. This is for the same reason that starlight is coherent, even though it was not so when it was emitted -- it has travelled a very large distance.
As I've already posted below, this is a fairly good explanation in simple terms.
The idea that laser light is coherent because of the in-phase emission of radiation is a misconception which has unfortunately been so widely disseminated that even some physicists believe it. It is a symptom of an education system based on rote memorization instead of critical thinking.
No, you are neglecting the other way that energy can be lost -- some of the photons are absorbed when they strike the mirror. By "light" I meant the entire assemblage of photons, not individual ones.
Wrong. Here is a good explanation in lay terms. You can find much more detailed explanations with a bit of digging.
Several people have now pointed this out. Maybe SF.net has changed their policies. But I'm fairly certain that a year and a half ago when I was investigating hosting a project there that the restriction was in place.
I don't look down the pipe that direction. To me, it's about being generous and not being hung-up about whether other people might benefit from something I've done. I honestly don't expect anything in return. For me, the mere fact that somebody else found my code useful enough to incorporate into a product is thanks enough.
Thus my prior comment about ideologies in Open Source. To me the most ideology-neutral thing to do is to just throw the code out there and not worry about who might use it in what way.
Then there's the practical problem the BSD license opens up by allowing embrace-and-extend, but let's not chase that rabbit.
I understand that argument, and it makes a bit of sense to me. It's just not important enough to change my choice of license.
It has to be, for efficiency purposes.
The reason laser light is coherent is because it travels an enormous distance before being emitted. This gives the individuals waves time to become coherent. Normally, this "enormous distance" is implemented by having the light bounce back and forth between two mirrors a large number of times. However, every time the light hits a mirror you lose a bit of energy. So, if the cavity is short, you must have a higher gain in order to get the required energy, because the laser has to make more reflections in order to travel the required distance to become coherent.
Hmmm, I'm getting hungry.
I don't follow. What freedom is being taken away from you? The ability to see somebody else's code? Why should you have a right to see code that somebody else wrote unless they want you to?
Only if you ignore the fact that most software companies' business models are based on selling software, not support. It's easy to just say "Well, they need to change business models" but that's not even approaching realistic.
The one argument against BSD-style licenses that makes at least partial sense to me goes like this:
Microsoft takes a piece of BSD-licensed software. They "embrace and extend" this software, causing it to be incompatible with the original version. Then, by leveraging monopoly power, they get the rest of the software world to use their version, thereby making the open version obsolete.
However, that only really matters to you if you have an ego. Really, who cares if anybody uses your software? You wrote it to fulfill your own needs, and the fact that it's been co-opted into something else doesn't change the fact that it still meets your needs and will continue to do so.
I don't think they'd do that -- the purpose behind the OSI-conformant requirement is to maintain an iron grip on the projects on SF.net. Allowing non-conforming projects to exist would invalidate the entire point of SF.net, which was to consolidate all OSS projects in one place where they can be controlled by the ideologues of the OSS movement.
It's a devilishly clever plan, really: authorize a bunch of less radical licenses, get tens of thousands of projects to move to SF.net, then rip the rug out from under everyone by forcing them to switch to the radical licenses, or risk losing their hosting. I wonder if this was planned all along...
True, but they can prevent you from hosting your project on SourceForge. SourceForge does not accept projects that don't use OSI-conforming licenses.
Stunts like the one we're discussing right now make it abundantly clear why relying on SourceForge to host the majority of OSS projects was a BAD idea. People come to rely on the services SF.net provides, but the OSI license requirement gives them a stranglehold over you.
What's your point? Either you give a binary along with source, or you just give source. In both cases, you give source.
You make it sound like the BSD license could be used to close a previous open piece of software. That's impossible. BSD license simply gives you more powerful rights over your own modifications to that software. Some people see that as a flaw, others (including myself) don't see what the big deal is about allowing other people to profit as long as it doesn't restrict our own rights to use the code we've written.
The usual response to that is that if you aren't willing to play the OSS game, you aren't allowed to use OSS code.
I think it's a juvenile attitude. "I willfully don't profit off my stuff so nobody else should either."
Of course, people are free to license things as they wish. I just think it's elitist to redefine the meaning of Open Source on a whim so that people who choose to release their code without restriction are no longer creating "open source."
The LGPL is a good compromise between the GPL and BSD licenses, although it's a little too wordy for my tastes.
In order to host your project on SourceForge it must use an OSI-conforming license. If the list of OSI-conforming licenses is drastically reduced what will happen to all the projects on SourceForge which don't use the GPL or BSD licenses? Will they just be booted off the server? Forced to switch licenses?
My God man, where did I complain about usability? I just said that buttons which go "poof" do nothing to improve it. In fact, given your strict delineation between the responsiblities of the X server and the windowing environment, I'd think you of all people would see the stupidity of buttons which go "poof" being implemented in the freaking X server.
It wouldn't be PDF getting sent directly to the video card either. PDF (or SVG) would serve as a close-to-the-metal format, but not actually run on the metal. Obviously it's translated into another form before actually going to the video card.
Do you really think that Quartz is literally sending PDF to the video card? PDF is just the standard vector format in their video drivers.
But, as usual, it's easier to call somebody a troll than actually debate something.
X is not a GUI, X is not responsible for usability.
Exactly. What this means is that the usability improvements need to happen in the WM layer, not the X layer. My point is that we don't need more garbage piled on to the X server. We need more effort directed at improving usability (again, that doesn't imply that it's not already usable, just that we should always strive to improve).
Now go back under your bridge and wait for the next Gnome or KDE post where you sound like less of an idiot with your tired complaints.
I use twm, but thanks for your stupid assumption.
But not all laws are just.
Breeding does not MODIFY the genes. It just mixes them into new combinations. GMO on the other hand have NEW genes that never existed before. Take some basic genetics.
But that's beside the point I'm about to make. Imagine the following scenario:
Monsanto patents some new GMO, say, tomatoes. These tomatoes interbreed with "natural" tomatoes. Soon, the patented gene has spread to all tomatoes thoughout the world. Now, Monsanto has a stranglehold on tomatoes, since they have a patent on every tomato on earth. Monsanto can now demand ridiculous sums of money, or they'll start suing every farmer on earth into bankruptcy. Either that, or simply revoke the permission to grow tomatoes, starving millions.
GMO must not exist so long as there are patents on GMO.
While I agree in principle on the need for hardware acceleration of PDLs (page description languages), can we PLEASE not use PDF as the standard? PLEASE?
Why not SVG, for instance?
Uh, how is that intuitive? The red light for closing the window might make sense. But yellow to minimize? A yellow light means "this light is about to turn red." So, by clicking the yellow light, what does that mean? That my window might close soon?
And green means "go." In the context of a computer application, "going" probably means using the app. What does maximizing a window have to do with "going" somewhere?
Don't flame me for being an Apple basher -- my Mini just shipped two days ago and I can hardly contain myself -- and I'm not trying to say that the red/yellow/green is counterintuitive, but I'm really not seeing the analogy to traffic lights.
Don't get me wrong -- I think X is "usable enough," but really, I don't think the moniker "next generation" is appropriate for anything but the most fundamental technological advances. Buttons that go "poof?" Is this seriously what we're concentrating our effort on?
My brother is actually in the film scoring business, and this is the normal state of affairs. Once the real score is finished they'll start using it. The music hasn't been "stolen," but fairly licensed.
Focusing on a product seems rather pointless if nobody wants to buy it. I still don't understand what's so corporate-speak about "consumer focus." Can you not grasp the meaning? I mean, we're not talking about synergizing our paradigms here...