Are you saying we shouldn't try, just because it won't be perfectly effective?
If the US does this, A) it will drastically cut down on spam, and B) it will probably be a step towards lots of other countries doing the same, which will lead to C) the near extiction of spam.
Hopefully this will eventually lead to the elimination of the distinction between ATA and SCSI interfaces. Already the feature distinctions between the two are blurring, hopefully soon the interface will be the same and people will just decide whether they need fast or cheap drives. That would improve the quality of desktop class drives and lower the price on workstation/server drives, as well as make system managment a bit easier.
There is some truth to this, but I have also experienced a drive for "recreational coding." When I am done with whatever butt-ugly program I work on for my day job, it can be nice to go home and work on something interesting to remind you why you like programming in the first place.
Of course, I could only take a couple of years of programming for a living before I had to quit, but I still enjoy coding for fun.
This is BS. Almost everything you say is wrong. It wouldn't bother me except for the "The replies you are getting are pretty half-assed..." bit.
LCD (liquid crystal displays) are constructed of a bunch of liquid crystal material sandwiched between glass plates. Liquid crystals are made of molecules that are very long and thin. In the nematic (or twisted nematic) phase, they line up to all point in the same direction (in twisted nematic, used in many LCDs, the orientation changes as you move between the two glass plates, but is locally the same). By making fine scratches in the glass plates, they can be forced to line up in specific directions, such that the rotate the polarization of light going through it by 90 degrees (or more for STN -- super twisted nematic). You then put polarizers on the faces and you have something that blocks light from a flourecent tube. By applying an electric field to the liquid crystal, the molecules rotate such that they don't rotate the polarization, and it now transmits light. Passive matrix LCDs scan one row at a time and rely on the liquid crystal molecules being slow to reorient to preserve them until the next scam, where as active matrix (TFT -- thin film transistor) displays have little transistors that hold a charge on each cell from one scan to the next.
The big problems with LCDs are that they need a backlight to get good contrast and that they throw away a lot of light because the lamp has to be on even when the pixels are black and a lot of light is lost to color filters to make different color pixels on RGB displays. Also, since it works by rotating polarization, it is very angle sensitive, and they are very slow.
OLEDs are an array of LEDs that are made with an organic polymer semiconductor. Like normal LEDs, they emit light when current passes through a diode, the wavelength of the light being dependent on the band gap of the semiconductor. However, it is much easier to make a fine grid of closely spaced pixels with OLEDs than regular LEDs. The solve almost all the problems of LCDs except that they tend to break down if any moisture gets into them, and water is extremely hard to get out and keep out so they tend to have a realatively short shelf-life. I assume that this problem has been mostly solved here, or a bunch of people are going to get cameras whose display will die within a year or two.
GCC (and I assume others) can do this. Basically, you compile with -fprofile-arcs, run the executable enough to generate sufficient data, then compile with -fbranch-probabilities. This will try to order basic blocks so that the CPU predicts branches correctly most often.
I have never done it, but it is supposed to work. Unfortunately, it is pretty much limited to static analysis -- it doesn't allow for programs whose usage patterns change with time. For that you need some kind of dynamic recompilation, such as provided by HP's Dynamo, Transmeta's code morphing, or perhaps some Java JITs (I don't know if any of them implement this).
Personally, I think profile directed optimization done by a static compiler is a waste of time. All optimizations should be done at the best place, and for many optimizations, that is the static compiler, but many others can be better done by run time optimizers, or the CPU, and this is one of them.
Yes, RISC programs tend to be longer (sometimes considerably) than CISC programs. There are actually two (main) reasons for this. First, as you mentioned, you need to replace single instructions (usually ones that do memory-to-register operations) with multiple operations (such as a load followed by an math operation). Second, the instructions themselves tend to be longer, since most (all?) RISC archetectures have exclusively 4-byte opcodes - usually something like 1 byte for the opcode, a few bits for flags, and the remaining for up to three arguments. (register numbers or immediate values). CISC archetectures have varying length opcodes, some a signle byte and some several bytes.
There are a couple of mitigating factors here. First, compilers are usually not very good at using some of the more complicated combined instructions, so they go unused, inflating CISC code to match RISC code. Second, careful optimization of RISC code can identify repeated or unecessary memory operations, and eliminate them. When the memory operations are tied to the arithmetic (or other) operation, that is not possible. Finally, since RISC archetectures generally have large register files and all registers are equivelent, fewer operations are needed to shuffle bits around to where they can be worked on, whereas i386 has a lot of operations that only work on certain registers (though far less than earlier incarnations).
I used to be a big fan of Intel cutting life support on the 386 archetecture, because RISC is so obviously cleaner and nicer. However, I have started to believe the AMD hype about x86-64, which is basically along the lines Linus talks about here. RISC vs. CISC doesn't really matter any more, and the i386 archetecture is not so bad. If you A) add some more general purpose registers, B) eliminate most of the remaining register usage restrictions, and C) Ditch the worst (looking and performing) FPU on the market in favor of almost anything else, you have yourself a very servicable archetecture. Extend the registers and addressing to 64 bits, and you have something that has a lot more room to grow. That is what the x86-64 is, and despite all the rumors that Intel has their own 64 bit extension to x86, if they don't actually release soon people will start to adopt x86-64 and they will be in the unenviable posistion of having AMD dictate the future of their product line.
I have heard frequently that something like only 5% of the transistors on the PPro core were tied to the "i386ness" of the core. I assume with the P4 that number is even less. It seems then that the instruction set is not as big of a deal as we would like to think.
The thing that puzzles me about ia64 is: if the whole point is to "make the compiler do it", and none of the fancy instruction reordering is done in silicon, why is it so expensive?
>Seemed like a plausible explanation of the adbuction experience.
I don't know what the appropriate magnetic fields are for this, but it could easily be that some other chemical or physiological thing triggers the same section of the brain as the magnetic field.
The magnetic field is a good way to study effects like this, but to conclude that stray magnetic fields are the cause of those sensations "in the wild" is specious reasoning at best.
I have been told that the X-ray dose you get from having an X-ray photograph taken at the doctor is about the same as what you get from taking a trans-atlantic flight due to being at higher altitude for 8 hours.
They really have medical X-rays working down to extremely low levels of radiation. Not something you want to be hit with every day, or several times a day (which is why the technitions leave the room) but not something that is a big deal to have happen periodically.
Oh, no! Because history teachers and activists are citizens.
Of course, if you read the link you posted, the guy is not actually complaining that a history teacher is a bad source (though he did object to the activism point, he didn't really explain himself well on that point), he is mocking the history teacher for his anti-war stance, saying he should have learned something from history. Which is a perfectly legitimate point to make, and reasonably well stated, though I happen to disagree with him.
The problem in the "call the editors" things is mostly that A) you have to say your bit in 30 words or less (at least in our paper), and that speaking to an answering machine is not a good way to allow people to do well thought out comments. The problem is more with the medium than the people.
Still, you catch a lot of people you wouldn't if you only took letters. That is why it is good to have both.
Well, letting people know it is wrong, for one. Convince organizations to stop encrouraging it, for another. Treat it as a social problem, first, and a technological problem second.
I think most people genuinely want to be honest, they just don't realize how big of a difference there is between submitting a letter that is their own vs. one that they agree with but didn't write.
Another idea: have a nice, friendly "so you want to write a letter to the editor" message in the opinion section and online that explains not only how to submit a letter to the editor, but how to go about writing one, suggests sources to look for information, that sort of thing. Sort of a 2 minute quick-start guide to writing that encourages people to read opinion statements from organizations supporting their cause fpr style guidance, but to write in their own words how they feel.
Hm. I filed a TAR a couple of years ago for a trivial bug which I had already completely diagnosed, related to a fixed bug in an earlier version of oracle, and posted the name of the function that needed to be altered, and 4 months later (when I left the company I was working for), they had not fixed it.
This was on the Linux version of 8.1.5 we used for development, and we were deployed on HP-UX, so it wasn't a huge issue, especially since I managed to patch it myself within a few days of reporting the bug, but I really expected better of them.
Even broken hard drives can be recovered, though it takes some rather expensive equipment to do so. However, with a little creativity and some equipment you would likely find in a EE department, much of it could be recovered.
SMP already can gain benefit from hyperthreading. However, an OS really needs special support to A) get the most out of hyperthreading and B) avoid worst-case scenarios, especially when you have both multiple physical CPUs and multiple logical CPUs per physical CPU.
For instance, if you have two processes running, you want to put them on different physical CPUs, and if you have a choice, grouping threads with the same memory image on a single processor improves cache usage.
There is no way to be sure of which? That high levels of C02 will definately cause climate change? I have never heard anyone with any kind of knowledge claim that. In a steady state, the total energy input from the sun and nuclear fission in the earths core have to balance total energy radiated into space. If we reduce the radiation into space, the earth will heat up until overall the energy out equals energy in. As I said, but may not have been clear on, is that our understanding of the system is poor enought that we don't know how much C02 it would take to make a substantial difference, nor how much natural carbon sinks will soak up excess emissions to restore an equilibrium, which is of course what matters. My statement was only meant in a theoritcal observation, not as something that directly translates into policy.
About the other thing, I think it is fair to say that most atmospheric scientits think there is a good change humans are causing climate change. There is no way to be sure, but it is a good chance. modulo concerns about defining probabilities for one-shot events.
In my personal opinion (and this is a political, not technical thing), the probability that we are causing climate change, the probability it will be harmful in the long run, and the potential cost of those things happening is great enough that we should be spending a fair amount more effort on minimizing our contribution to greenhouse gasses.
It is just like wearing your seatbelt. Odds are, you aren't going to be in an accident any given time you get in the car, but the cost of guessing wrong is high, and the cost of reducing the likelihood of serious injury is low.
And yes, I have read a good chunk of the report to the UN.
Take what environmental groups say with salt, but almost all scientits who study this field say that there is a very good chance that humans are affecting global climate change. This is based on lots of climate simulation data and other sources that are not conclusive (since it is a little hard to run such experements on the real earth), but provide a really solid argument that it is worth our effort to reduce greenhouse emissions in case we are doing something bad.
And it is definately true that higher atmospheric levels of CO2 will increase the average global temperature. The questions that are ambigious are to what extent, and how C02 emissions interact with the carbon cycle to determine total atmospheric C02.
Hm. I take that one step further. I have an answering machine and no caller ID. If someone calls when I don't want to answer it, they can leave a message. It took me some time, but I trained myself that I can sit and eat and let the phone ring without having to get up and answer it.
It is very liberating to hear a phone ringing and not feel like you have to answer it.
I love my TiVo, but I understand why some people would want a more "open" system, either to be able to customize it, add features, be faster, etc.
Also, there is the threat of TiVo's insolvency. If they go belly up and the TiVo service stops working, I will be left with a glorified VCR.
Until my TiVo or their business fails, I am not going to look for a replacement, but if would be cool if there were software I could use on an old computer I already have if it comes to that.
You don't think if it was that easy, something like it might have evolved by now?
I am not saying that this kind of stuff isn't dangerous, but I think the "grey goo" possibility is more than a bit far fetched, and to have pompus jackasses who like to be quoted using it for publicity even damages the credibility of smart, hard working people who are trying to rationally analyize the real dangers of nano-tech and bio-engineering.
This is not a moral issue (though some people may have moral issues with it). This is not an issue to be addressed by making impassioned speaches, or eloquent essays backed by political ideologies. There are right answers here. we have or can learn what we need to make good, well-informed decisions.
What kind of small minded demon of impotence are you? If I really believed that we would never get off this planet, I would probably have to kill myself. Mankind's destiny is in the stars, and if it takes a hundred years or a hundred thousand, we will make it there.
If for no other reason, one day, Sol will die. I, or my intellectual heirs, plan to leave by then. You are welcome to stay.
We have a 5 billion year reprieve on that, so I am not too worried about that today, but I do think about it from time to time. And as a "real" scientist (as opposed to SF), I like to think I am doing a bit to get us to that point.
In the mean time, we still owe it to ourselves to work out the space travel thing (which I have no doubt we will). The universe a giant playground, and it seems kind of booring to spend our whole lives on one planet.
Slashdot Mirror
Are you saying we shouldn't try, just because it won't be perfectly effective?
If the US does this, A) it will drastically cut down on spam, and B) it will probably be a step towards lots of other countries doing the same, which will lead to C) the near extiction of spam.
Hopefully this will eventually lead to the elimination of the distinction between ATA and SCSI interfaces. Already the feature distinctions between the two are blurring, hopefully soon the interface will be the same and people will just decide whether they need fast or cheap drives. That would improve the quality of desktop class drives and lower the price on workstation/server drives, as well as make system managment a bit easier.
Physics. I am currently in grad school. It doesn't pay as well, but I get to keep my soul...
There is some truth to this, but I have also experienced a drive for "recreational coding." When I am done with whatever butt-ugly program I work on for my day job, it can be nice to go home and work on something interesting to remind you why you like programming in the first place.
Of course, I could only take a couple of years of programming for a living before I had to quit, but I still enjoy coding for fun.
This is BS. Almost everything you say is wrong. It wouldn't bother me except for the "The replies you are getting are pretty half-assed..." bit.
LCD (liquid crystal displays) are constructed of a bunch of liquid crystal material sandwiched between glass plates. Liquid crystals are made of molecules that are very long and thin. In the nematic (or twisted nematic) phase, they line up to all point in the same direction (in twisted nematic, used in many LCDs, the orientation changes as you move between the two glass plates, but is locally the same). By making fine scratches in the glass plates, they can be forced to line up in specific directions, such that the rotate the polarization of light going through it by 90 degrees (or more for STN -- super twisted nematic). You then put polarizers on the faces and you have something that blocks light from a flourecent tube. By applying an electric field to the liquid crystal, the molecules rotate such that they don't rotate the polarization, and it now transmits light. Passive matrix LCDs scan one row at a time and rely on the liquid crystal molecules being slow to reorient to preserve them until the next scam, where as active matrix (TFT -- thin film transistor) displays have little transistors that hold a charge on each cell from one scan to the next.
The big problems with LCDs are that they need a backlight to get good contrast and that they throw away a lot of light because the lamp has to be on even when the pixels are black and a lot of light is lost to color filters to make different color pixels on RGB displays. Also, since it works by rotating polarization, it is very angle sensitive, and they are very slow.
OLEDs are an array of LEDs that are made with an organic polymer semiconductor. Like normal LEDs, they emit light when current passes through a diode, the wavelength of the light being dependent on the band gap of the semiconductor. However, it is much easier to make a fine grid of closely spaced pixels with OLEDs than regular LEDs. The solve almost all the problems of LCDs except that they tend to break down if any moisture gets into them, and water is extremely hard to get out and keep out so they tend to have a realatively short shelf-life. I assume that this problem has been mostly solved here, or a bunch of people are going to get cameras whose display will die within a year or two.
GCC (and I assume others) can do this. Basically, you compile with -fprofile-arcs, run the executable enough to generate sufficient data, then compile with -fbranch-probabilities. This will try to order basic blocks so that the CPU predicts branches correctly most often.
I have never done it, but it is supposed to work. Unfortunately, it is pretty much limited to static analysis -- it doesn't allow for programs whose usage patterns change with time. For that you need some kind of dynamic recompilation, such as provided by HP's Dynamo, Transmeta's code morphing, or perhaps some Java JITs (I don't know if any of them implement this).
Personally, I think profile directed optimization done by a static compiler is a waste of time. All optimizations should be done at the best place, and for many optimizations, that is the static compiler, but many others can be better done by run time optimizers, or the CPU, and this is one of them.
Yes, RISC programs tend to be longer (sometimes considerably) than CISC programs. There are actually two (main) reasons for this. First, as you mentioned, you need to replace single instructions (usually ones that do memory-to-register operations) with multiple operations (such as a load followed by an math operation). Second, the instructions themselves tend to be longer, since most (all?) RISC archetectures have exclusively 4-byte opcodes - usually something like 1 byte for the opcode, a few bits for flags, and the remaining for up to three arguments. (register numbers or immediate values). CISC archetectures have varying length opcodes, some a signle byte and some several bytes.
There are a couple of mitigating factors here. First, compilers are usually not very good at using some of the more complicated combined instructions, so they go unused, inflating CISC code to match RISC code. Second, careful optimization of RISC code can identify repeated or unecessary memory operations, and eliminate them. When the memory operations are tied to the arithmetic (or other) operation, that is not possible. Finally, since RISC archetectures generally have large register files and all registers are equivelent, fewer operations are needed to shuffle bits around to where they can be worked on, whereas i386 has a lot of operations that only work on certain registers (though far less than earlier incarnations).
I used to be a big fan of Intel cutting life support on the 386 archetecture, because RISC is so obviously cleaner and nicer. However, I have started to believe the AMD hype about x86-64, which is basically along the lines Linus talks about here. RISC vs. CISC doesn't really matter any more, and the i386 archetecture is not so bad. If you A) add some more general purpose registers, B) eliminate most of the remaining register usage restrictions, and C) Ditch the worst (looking and performing) FPU on the market in favor of almost anything else, you have yourself a very servicable archetecture. Extend the registers and addressing to 64 bits, and you have something that has a lot more room to grow. That is what the x86-64 is, and despite all the rumors that Intel has their own 64 bit extension to x86, if they don't actually release soon people will start to adopt x86-64 and they will be in the unenviable posistion of having AMD dictate the future of their product line.
I have heard frequently that something like only 5% of the transistors on the PPro core were tied to the "i386ness" of the core. I assume with the P4 that number is even less. It seems then that the instruction set is not as big of a deal as we would like to think.
The thing that puzzles me about ia64 is: if the whole point is to "make the compiler do it", and none of the fancy instruction reordering is done in silicon, why is it so expensive?
>Seemed like a plausible explanation of the adbuction experience.
I don't know what the appropriate magnetic fields are for this, but it could easily be that some other chemical or physiological thing triggers the same section of the brain as the magnetic field.
The magnetic field is a good way to study effects like this, but to conclude that stray magnetic fields are the cause of those sensations "in the wild" is specious reasoning at best.
I have been told that the X-ray dose you get from having an X-ray photograph taken at the doctor is about the same as what you get from taking a trans-atlantic flight due to being at higher altitude for 8 hours.
They really have medical X-rays working down to extremely low levels of radiation. Not something you want to be hit with every day, or several times a day (which is why the technitions leave the room) but not something that is a big deal to have happen periodically.
Oh, no! Because history teachers and activists are citizens.
Of course, if you read the link you posted, the guy is not actually complaining that a history teacher is a bad source (though he did object to the activism point, he didn't really explain himself well on that point), he is mocking the history teacher for his anti-war stance, saying he should have learned something from history. Which is a perfectly legitimate point to make, and reasonably well stated, though I happen to disagree with him.
The problem in the "call the editors" things is mostly that A) you have to say your bit in 30 words or less (at least in our paper), and that speaking to an answering machine is not a good way to allow people to do well thought out comments. The problem is more with the medium than the people.
Still, you catch a lot of people you wouldn't if you only took letters. That is why it is good to have both.
Well, letting people know it is wrong, for one. Convince organizations to stop encrouraging it, for another. Treat it as a social problem, first, and a technological problem second.
I think most people genuinely want to be honest, they just don't realize how big of a difference there is between submitting a letter that is their own vs. one that they agree with but didn't write.
Another idea: have a nice, friendly "so you want to write a letter to the editor" message in the opinion section and online that explains not only how to submit a letter to the editor, but how to go about writing one, suggests sources to look for information, that sort of thing. Sort of a 2 minute quick-start guide to writing that encourages people to read opinion statements from organizations supporting their cause fpr style guidance, but to write in their own words how they feel.
Hm. I filed a TAR a couple of years ago for a trivial bug which I had already completely diagnosed, related to a fixed bug in an earlier version of oracle, and posted the name of the function that needed to be altered, and 4 months later (when I left the company I was working for), they had not fixed it.
This was on the Linux version of 8.1.5 we used for development, and we were deployed on HP-UX, so it wasn't a huge issue, especially since I managed to patch it myself within a few days of reporting the bug, but I really expected better of them.
Actually, LCDs do get substantially harder to make as they get larger.
I think the poster meant that outlook doesn't show the BCC field when composing mail unless you enable rich headers.
FWIW, at least Pine has this characteristic, too.
The linux kernel has supported that as a random source for /dev/[u]random for some time now.
> Just like for the rest of the world
exactly the same way that the eastern US is east of the prime meridian and west of the IDL?
Your defenition is perfectly fine, but it is not what we mean by "western X" where X is not "antarctica" or "earth".
Even broken hard drives can be recovered, though it takes some rather expensive equipment to do so. However, with a little creativity and some equipment you would likely find in a EE department, much of it could be recovered.
SMP already can gain benefit from hyperthreading. However, an OS really needs special support to A) get the most out of hyperthreading and B) avoid worst-case scenarios, especially when you have both multiple physical CPUs and multiple logical CPUs per physical CPU.
For instance, if you have two processes running, you want to put them on different physical CPUs, and if you have a choice, grouping threads with the same memory image on a single processor improves cache usage.
Without this, hyperthreading may
There is no way to be sure of which? That high levels of C02 will definately cause climate change? I have never heard anyone with any kind of knowledge claim that. In a steady state, the total energy input from the sun and nuclear fission in the earths core have to balance total energy radiated into space. If we reduce the radiation into space, the earth will heat up until overall the energy out equals energy in. As I said, but may not have been clear on, is that our understanding of the system is poor enought that we don't know how much C02 it would take to make a substantial difference, nor how much natural carbon sinks will soak up excess emissions to restore an equilibrium, which is of course what matters. My statement was only meant in a theoritcal observation, not as something that directly translates into policy.
About the other thing, I think it is fair to say that most atmospheric scientits think there is a good change humans are causing climate change. There is no way to be sure, but it is a good chance. modulo concerns about defining probabilities for one-shot events.
In my personal opinion (and this is a political, not technical thing), the probability that we are causing climate change, the probability it will be harmful in the long run, and the potential cost of those things happening is great enough that we should be spending a fair amount more effort on minimizing our contribution to greenhouse gasses.
It is just like wearing your seatbelt. Odds are, you aren't going to be in an accident any given time you get in the car, but the cost of guessing wrong is high, and the cost of reducing the likelihood of serious injury is low.
And yes, I have read a good chunk of the report to the UN.
Take what environmental groups say with salt, but almost all scientits who study this field say that there is a very good chance that humans are affecting global climate change. This is based on lots of climate simulation data and other sources that are not conclusive (since it is a little hard to run such experements on the real earth), but provide a really solid argument that it is worth our effort to reduce greenhouse emissions in case we are doing something bad.
And it is definately true that higher atmospheric levels of CO2 will increase the average global temperature. The questions that are ambigious are to what extent, and how C02 emissions interact with the carbon cycle to determine total atmospheric C02.
Hm. I take that one step further. I have an answering machine and no caller ID. If someone calls when I don't want to answer it, they can leave a message. It took me some time, but I trained myself that I can sit and eat and let the phone ring without having to get up and answer it.
It is very liberating to hear a phone ringing and not feel like you have to answer it.
I love my TiVo, but I understand why some people would want a more "open" system, either to be able to customize it, add features, be faster, etc.
Also, there is the threat of TiVo's insolvency. If they go belly up and the TiVo service stops working, I will be left with a glorified VCR.
Until my TiVo or their business fails, I am not going to look for a replacement, but if would be cool if there were software I could use on an old computer I already have if it comes to that.
You don't think if it was that easy, something like it might have evolved by now?
I am not saying that this kind of stuff isn't dangerous, but I think the "grey goo" possibility is more than a bit far fetched, and to have pompus jackasses who like to be quoted using it for publicity even damages the credibility of smart, hard working people who are trying to rationally analyize the real dangers of nano-tech and bio-engineering.
This is not a moral issue (though some people may have moral issues with it). This is not an issue to be addressed by making impassioned speaches, or eloquent essays backed by political ideologies. There are right answers here. we have or can learn what we need to make good, well-informed decisions.
What kind of small minded demon of impotence are you? If I really believed that we would never get off this planet, I would probably have to kill myself. Mankind's destiny is in the stars, and if it takes a hundred years or a hundred thousand, we will make it there.
If for no other reason, one day, Sol will die. I, or my intellectual heirs, plan to leave by then. You are welcome to stay.
We have a 5 billion year reprieve on that, so I am not too worried about that today, but I do think about it from time to time. And as a "real" scientist (as opposed to SF), I like to think I am doing a bit to get us to that point.
In the mean time, we still owe it to ourselves to work out the space travel thing (which I have no doubt we will). The universe a giant playground, and it seems kind of booring to spend our whole lives on one planet.