I just wanted him to define the word trusted to AMI pretty much. I have a pretty good idea of the difference between my use of the word trust, and the Media market's use of the word.:)
Some users will trust the wrong programs, its inevitable. On the other hand, I think a lot of people wouldn't. To them, it would actually be useful. You don't not make a tooth brush because some people won't brush their teeth.
What we don't have today is a "Run in sandbox" option. We really need a stricter way of defining what a program can do. Say you get an e-mail with a program attatched. It's supposed to sing and dance. You should have check boxes that will not ever let this program sing and dance again, let it sing, but not let it create a window, or let it dance, but not make noise. By no means should this program be allowed to open files or network connections. Of course you could have a dumbed down version for the not so smart that says "This program wants to open windows and play music, do you want to allow this?" Then with the virus code tries to open a file or network connection or try to talk to the mail program, it will say "This program is trying to use your email/internet connection/open files on your disk... Should I let it?" Most users I think would be ok with this. If not, at least it could be configured in the ID-10T mode where they trust someone else to verify if a program is safe. Say you set up a computer for grannie in idiot mode. She gets all her trust from your certification server, and when she needs to run something you or a buddy hasn't tested to be ok, then she calls you and you add it for her. No more viruses for grandma. Then when sites are verified, no more (or a lot less) porn for children. It's all around a good deal if it's implemented properly.
I actually like the concept of trusted computing quite a bit. So long as the user selects which code will be trusted, it has great potential for good. My question is, from your position, do you foresee trusted computing being more like web-browser applet signing applied in hardware (where the user can add and remove trust for certain companies) or more like the media industries idea (where the OS/hardware manufacturers select which code is trusted under penalty of DMCA)?
I guess you have to apply the theory of the nature of relativity to see what I'm saying to begin with. In a phrase, it says we live in a ship in a bottle. Our perspective is distorted in order to make c a constant, and the speed of gravity~=c, the speed of light=c. From his other works, he says that light travels as both a particle and a wave (what doesn't?). The speed of light on the wave does not conform to his theory, but merely that the wave scrunches as to not travel in a ray faster than the speed of light. That's where I have to call BS. According to his own math, it should be impossible to achieve the speed of the photon along the wave. I could accept that it travels on a wave and the gravity isn't instant. This could account for the wave itself. This is a known problem with the theory of relativity, it doesn't apply on a small scale.
Now, since he assumed that nothing travels faster than the speed of light (but light itself does), his equations are going to be loaded. Lets say the speed of gravity is c-e^(-x). No matter what you put in x (as long as it's large), it's going to give you ~ c. I don't feel like looking up the real equations and spending a year playing with Einstein math to show it, but just for an example, it would take infinite energy to go the speed of light. Verticle assumtope's aren't hard to come up with.
More or less, what I'm saying is that the speed of the particle that feels the gravitational pull and it's mass will have to be used in the equation too, and that's going end up approximately cancelling out the speed and mass of Jupiter, leaving ~c in a relativistic equation. That's how relativity works.
A better experiment would have not used the theory of relativity to measure the speed of gravity. Measure the direction of the gravitational pull, and compare it to the direction of the light. The moon is ~500,000 miles away, and we can feel it's gravitational pull very easily.
yeah, you could use a ruler and a compass to confirm it, but he didn't.
No, the gravity wave experiment couldn't have gotten a value that far off if he conducted it properly. Explain how he could have?
I assume that Jupiter's mass and velocity are not in dispute? All he did is measure Jupiter's gravitational pull (I wonder how he accounted for enough of the other mass in the universe to get an accurate number). What formula did he then use to get the speed of gravity? According to the article, it was a formula from the theory of relativity. Since the theory was pretty clear that the speed of gravity is near c, I don't see how you could have a hard time seeing that it was obvious that he was going to get that number.
Besides, the best way to compare the speeds would have been to measure the angle between the direction of the pull and the direction of the light. Kind of like watching a plane fly over head. You see it in front of the source of it's sound.
So there, I have given you a great way to determine the speed of gravity relative to light without using relativity to calculate the speed of gravity. It's no more difficult to measure the angle to the source of the gravity than the gravitational pull(which he measured). If that shows that the speed of gravity is c, then he can use that to back the theory of relativity.
I just wished people would stop trying to prove their hypothesis with itself.
A ruler measures itself. That's what it does. You compare other objects to it to get their size. Don't be silly.
My point exactly is that you need to know what a yard is first. You can't use the hypothesis to prove the hypothesis, else you would be right to call it a yard even though it's 10 inches.... and no, 10 inches is not a yard.... and yes, you would be wrong to say it is.
He didn't measure the speed of gravity from what I can tell. He measured other variables then used equations from the theory of relativity to determine the speed of gravity. If that's not what he did, then he wouldn't have needed the theory of relativity to calculate the speed of gravity (the article said he did).
"He reworked the equations of general relativity to express the gravitational field of a moving body in terms of its mass, velocity and the speed of gravity. If you could measure the gravitational field of Jupiter, while knowing its mass and velocity, you could work out the speed of gravity."
Read it carefully. He used mass, velocity, and the gravitational field to measure the speed of gravity. So he measured mass, velocity, and the gravitational pull of Jupiter. He used the theory of relativity then to calculate the speed of gravity. If he didn't, I would like to see the formula that he did use and know where he found it.
You can't use the formulas of a hypothesis to gauge their accuracy against themselves. Einstein made those theories with the idea that gravity move at c. Therefore, any measurement you make, with his math, will make it look like c. It may be 2c, but if his math says that gravity is.5 it's actual speed, then after you take the.5, it will be c again.
The point is, his hypothesis was more like "the speed of gravity is c", and he used the theory of relativity to show that it is so. He makes it out like now that he has shown the speed of gravity to be c, it somehow strengthens the arguement for relativity. His original experiment assumed the theory of relativity, therefore, his findings are only as accurate as the theory of relativity. So, the speed of gravity being c is only as reliably as the theory of relativity. Therefore, when you use this to argue as a strength for the theory of relativity you end up with: The theory of relativity is only as reliable as the theory of relativity.
Absolutely correct definition of a theory, but incorrect definition of a evidence. Evidence can be in the form of an experiment, but only if the experiment is independant of the hypothesis. You can't say your ruler is a yard, then use it to measure itself as evidence that your ruler is a yard long.
At least I didn't assume the article was correct then use it to argue that the article was correct:)
If I assumed the world is flat, I could probably show that it has an edge. That doesn't mean that that the world is flat or round, because the premise of the experiment was flawed. If I assume the world is flat, and I have no proof, then I can only prove that my assumption is false. There is no evidence presented in his experiment that shows that the theory of relativity is true. In fact, his experiment doesn't grant one shred of knowledge. If you substitute a false equation into itself, you will still end up with a true statement. That sheds no light on the viability of the original statement one way or the other.
No it shows absolutely nothing. It shows that if you assume GR, then a sub assumption of GR can be proven. If I use trig for a given, I better find PI~=3.14!
Let me put this into simple terms so you can understand.
He used principals of relativity to measure the speed of gravity. Relativity is still a theory with no means of being proven in the foreseeable future. Based on his unjustified assumption, he calculated the speed of gravity to conform to his assumption.
Ex) I say chickens lay square eggs, but the universe is warped to make them appear to be ovals. I make a mathmatical calculation to calculate the true form the the egg (a square) from the oval. What this guy did is assume that the eggs are square, then used my calculation to show that they are approximately square. Are the eggs really square?
"Isaac Newton thought the influence of gravity was instantaneous, but Einstein assumed it travelled at the speed of light and built this into his 1915 general theory of relativity."
According to the theory of relativity, nothing travels faster than the speed of light. Then again, gravity travels really fast. Therefore, gravity more than likely travels at near the speed of light.
"Kopeikin found another way. He reworked the equations of general relativity to express the gravitational field of a moving body in terms of its mass, velocity and the speed of gravity. If you could measure the gravitational field of Jupiter, while knowing its mass and velocity, you could work out the speed of gravity."
The theory of relativity was appearantly used to detect the speed of gravity. This would be fine if the theory of relativity didn't assume a speed of gravity. Basically, all he did was prove his given. So, if eggs are green, then eggs are green!
MS has a porting tool that is supposed to work with 99% of all Java code. It probably won't work well with obscure API's or JNI, but I here it is indeed pretty magical. It makes the conversion process easy enough to play with for small apps. Larger apps will still take some grunt work I'm sure.
Swing is a nice GUI API, IMO. Like you though, it pains me too see GUI's written in Swing. Not because SWT is better, but because no one takes the time to use layouts properly. The end product is a GUI that looks and feels like VBA by a cheap contractor. I've seen good Swing applications, but they are as rare as good MS products. Maybe Luxor(XUL for Java) or one of it's kin will make UI design as easy as web design. Then only 50% of them will suck. The biggest problem with UI design in Java is that it's done by a programmer that only cares about functionality (a lot like me) and not by an artist (like the Mac UI). Swing isn't what makes apps slow. GC doesn't make Java slow. Poor programming habbits are the #1 cause of sluggish UIs.
With MS having to carry a decent JVM on the desktop now, you can expect to see a lot more apps for the desktop written in Java. If only SUN would lighten up on the license so it can be included on Linux....
An interesting side note: Since the judge ordered MS to carry Sun's JVM, does MS have to agree with the license for distrobution? Can they not ship competing technologies like J++ for.Net on Windows?
You can, and it doesn't have to be an American citizen that got it either. As long as the board members are in the US, you can bring them up on charges. They'll pin them on an Indian exec, but the company will have to hold it's head in shame from the publicity. That's why there are conspiracy crimes (conspiracy to commit murder etc.) and accessory crimes (even if they know what would happen, they are accessories since they have the power to stop it).
Re:You misunderstand completely
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E ~ mc^2
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· Score: 2, Interesting
Surely there would be a simpler way of explaining how the speed of light could be constant. Even if there wasn't, I think it's nearly impossible to falsify. No matter what sane experiment people come up with that bends it, someone always claims it doesn't break it. If I said we all live in the Matrix, you may be able to bend my theory, but not break it. This is basically what the theory of relativity is. The theory of relativety says we live inside a warped universe. Our mass and our dimension changes depending on our speed. Which boarders contradiction of conservation of matter.
Then you have to consider that photons created by different orbitals are different wavelength. Where does that fit in to the theory? It's called different "energy" photons. This energy can't make the photon go faster, so it bounces more? Doesn't that make it go faster along the wave? If so, then does the theory mean you can't travel in a straight line faster than c? Then the theory falls apart for any peice of the wave.
The cesium chamber experiment alone proves that either the cesium chamber was moving at phenominal speeds without us seeing it, c ~ infinity, or the chamber is shorter than was measured. Some experiments actually get photons out before they go in. According to everything I've read about the theory, "all calculations of the speed of light will be the same to any observer." This clearly isn't true in the cesium condensate experiment.
Really now... Occam's Razor tells me that it would be much easier to believe that we can't measure the speed of light properly with our equipment, and it could be possible to travel faster than light. This is especially true considering that c is the speed of light in a ray at an ungiven wavelength instead of the speed of a photon along a wave.
There are more complications caused by the theory of relativity than those it sought to fix. I would rather go back to the original failures of the "classic" equations and fix whats wrong than fix a theory that seems to generate loop holes every month. It would be easier to scrap it and solve the original problems than make a patchwork theory.
Ok, If you don't say that the Pipeline allowed them to get 2x the clock speed (the fastest Athlon is 2.17 Ghz ATM), then I won't say that it hasn't let them crank out an extra 38% cycle speed.
If they catch branches early on (by the 5th stage), then they will not loose much performance. But because there are 10 instructions still not complete, it's unlikely they could catch the branch until all the instructions are complete and ready to write back to ram. Consider also the super scalar nature of the CPU. Now we are sitting around the 13th stage of the pipeline and we know which way to branch. If we were wrong, we loose 12*2=24 clock cycles. If branch prediction is 90% accurate(a stretch I would say) and code is about 10% branch statements, then 1 in every 100 instructions will cause you to loose 24 clock cycles. That's only branching! Now lets take that 20% of the time, the next instruction references the result of the current instruction. That usually causes the processor to insert NOPs into the pipe just after the decode until there is enough spacing between them so that the data can be forwarded to this instruction when it is ready for it's operands. In a normal pipe, that's only about 2 clock cycles. In a P4 pipe, that has to at least be 6. This is a factor or 3 slower about 20% of the time. That's about the same for branches. A good 1/3 of the cpu time is 3x slower on a P4. Sure you can compile around some of it, but that is just silly. That's why P4 introduced hyper threading that nothing is using. So instead of inserting NOPs, it can insert instructions from other programs that can't possibly reference the same data. That would be great, but it can be applied to shorter pipes just as well.
The majority of the performance increase of P4 has nothing to do with the pipeline. If the P4 was built on a normal pipeline, you could have expected to see a 2.2 Ghz machine right now that blew the AMD away.
Intel had a good chance with their Itanium to make a good RISC processor. A good load-store, 4/8 way super scalar, with a short pipeline, and it could still do 3Ghz easy. Instead, they decided to graft on the kitchen sink and a million other transistors that will lie dormant half the time. Most of the CPU will be sleeping even when you need it. I'm more excited about the new IBM processors for the mac.
A 50 stage pipeline wouldn't be bad if it were done differently. I still prefer the old "have one instruction after the branch that always is executed" method. Only with a longer pipeline, you would need more instructions. A good optimized compiler could handle this MUCH better than a processor could. Longer pipelines need better branch prediction. I don't really care about your research, because it's all theory. It's pretty appearant from comparing P3 to P4 that longer pipelines are only better if you can manage to crank out a factor of speed greater than the factor of increase in pipeline length. The whole "Software isn't compiled for P4 optimizations" arguement is really dumb when you think about it. If it can't run X86 faster, then it must really suck. In order to compensate for this, they have to run the P4 at much faster clock rates, and the compiled binaries have to be larger so as to place the jump points in strategic positions. Deeper pipelining will cause you to run into problems of silicon transistor switching speed much earlier than you would usually as well.
Rambus is a bad idea. It had very much inferior latency that increased with each memory module you add. The processor waits everytime you ask for ram. That's wasted cycles. There is a reason the P4 has an internal bus that is VERY wide compared to other processors. DDR's memory speed is in no way related to the bus's inferiority. The faster you make the chips, the faster the processor gets the data. With RAMBUS, you have additional latencies for the same speed of RAM. They are all made from the same DRAM design, and with the same speed chips, a wider bus will be faster.
I'm not upset that the Itanium changes instructions sets. I just don't think that any processor that disables part of itself will ever be optimal. I don't think lugging around old instruction sets are a good idea either. It's a waste of space that could have been used for some more full multipliers.
Don't take my word for it... go clock a P4 against another CPU and see how well it performs in sorting with RAMBUS memory. The bulk of the P4's gains on any other CPU comes from SSE2, 400Mhz FSB, and CPU clock speed. Take those away, and it will be slower per clock cycle than any other CPU (including P3), especially if it has RAMBUS memory.
Now everyone will know why the P4 sucks:) Honestly, in order to double the pipelines length, you really need to be twice as accurate with branch prediction, or else it will be slower per clock speed. It does make it easier for a chip to go faster, to a certain point, but the P4 is a bit excessive:) I just wonder sometimes if the Intel designers have ADD (think rambus (bad idea... memory width is a good thing!), P4 (don't increase the pipeline's length unless you have a good reason), Itanitium (scrap an entire architechture for one that allows you to disable instructions, so that it is gauranteed that part of the processor won't be used at that point)).
Something to combat md5sum itself from being cracked. Perhaps a statically compiled binary that you can download with the program of your choice. Then rootkits would have to modify every program that can download a file, or the kernel. The best system would be a nice bootable CD that would scan all known file system types for files that have md5 sums of known bad files, not search for files and make sure they have a md5 sum of a good file. Then root kits will have to rely on a compiler or append random bytes to the end of the files.
Well this gets so complicated that by the time you've thought it all out, you really need virus scanner technology to thwart root kits. Maybe a kernel patch could run a virus scan on executable files? It would be quite difficult to tamper with the actual running kernel in memory without causing the system to lock or reboot, thus giving away that the system is being tampered with. Assuming root kits are distributed in source form, you'll need heuristic scanning to find them. This means false positives and manual overides by the system administrator.
is helping the terrorists too... they just let anyone come in and purchase food. Those terrorists couldn't have made it to the planes if they had starved first! This will end terrorism because terrorists are too stupid to buy an AOL account!!!
This statement by the Dept. of Homeland Security was probably funded by AOL/Verizon/etc.
Don't forget --help / -h not talking about the configuration file, then man saying "This file/program has no man page, here is command -h, or see this website" When you go to the website, there is a FAQ, but no configuration example. Then the configuration path has to specified at compile time. Sometimes the configuration is stored in DB files in either TDB or BDB format of which there is no easy way to examine. Then you have to run make in some obscure directory on some programs to generate these files again from the text files. Then half the programs don't have a configuration reload option, but you just have to shut them down and restart them. If the new configuration is bad, it dies with an obscure error, or quietly. After digging through/var/log you might find some hint at where the problem is.
I can't believe that Linux people complain about the registry when they have this POS method for configuration. I'ld take the registry any day./etc could easily be replaced by one DB (LDAP-ish, but local) that is the registry and have a system library so all programs can access configurations in a standard way. I would prefer very much an editor that at least told me what I could set and had a range of values. Then it wouldn't require much to include a help database explaining each field's meaning. Parsing text that users write directly was never a good idea for configuration.
Then there is that god-aweful horrible X protocol. I don't care about all the third party support for it, it would be better to have a display that worked on one computer than one that half works on a million computers. I could run Win95 just fine on a 486 with 16M ram, but X would grind away at the hard disk for 10 minutes before it would start. I would rather have the Palm's GUI than any of the intrusive window managers out there. The one's that are clean require you to click through a menu 8 levels deep to find the program you want to run. I don't think users would be so opposed to pressing a hot key for a full screen menu with drag and drop support for their programs. I don't have to edit some hidden txt file under windows to change the menu. KDE lets you add icons to the desktop, and it lets you customize the menu, but it's really slow compared to any other OS's menus, and it's not very smart when it comes to clicking programs/files, because linux has "magic" instead of a good MIME typing system or extensions. XFS has support for adding attributes directly to the files, thus making it possible to store the MIME type with the file instead of as an extension, but no other file system supports it, thus there are no programs that do. This problem can be pinned directly on the linux kernel itself because the EXT filesystem s are the dumbest file systems since FAT. I thought it would be common sence to implement ACL's and Attributes, even more so if you aren't going to use brain-dead filename extensions.
The more I work with Linux to replace windows, the more I see the problems that arise from a million uncoordinated people hacking away at the same system. There is no consistency.
Re:I was lucky enough to see one of these in actio
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Transmeta Astro Processor
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· Score: 5, Informative
Are you a troll?...lack of sse2... It doesn't even run X86 natively!...uses an astonishing amount of ram...64mb... 64mb or ram costs 15$ The price difference between the P4 and the transmeta will easily be more than that. Buy more ram!...unstable... It hasn't even been released. Kernel 2.5 isn't all that stable, but no one complains because it is a testing/prototype....only run at agp 2x... The speed of the agp bus has been shown to be inconsequential to the performance.
The rumor is that the demo chip is running at 500Mhz at the moment. Comparing that to the 1.8ghz P4 suddenly doesn't seem so out of proportion does it? I gaurantee you it will be running at at least 1ghz when it's finally released. The final board for it (not the notoriously shoddy reference boards) will perform better as the memory bandwidth will probably be improved.
What if I had done the same review of the Itanium 6 mo. before it was released? It was running at 400Mhz, couldn't run X86 software as fast as a 266, and was practically an unstable toaster oven.
Try a different JVM if at all possible.. If not, you can configure the JVM to compile useing jikes. The problem you probably have is that the toy compiler that comes with the JDK that's written partially in java, turns out to leek memory (just enough to be annoying if you have a lot of JSPs). There are how-to's online for setting up jikes and tomcat. This issue has been known for a while, but SUN nor Tomcat feel like it's a big enough issue to get upset about. You could also have a look at Jetty which is faster than Tomcat and more stable and yet easier to set up.
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I just wanted him to define the word trusted to AMI pretty much. I have a pretty good idea of the difference between my use of the word trust, and the Media market's use of the word. :)
Some users will trust the wrong programs, its inevitable. On the other hand, I think a lot of people wouldn't. To them, it would actually be useful. You don't not make a tooth brush because some people won't brush their teeth.
What we don't have today is a "Run in sandbox" option. We really need a stricter way of defining what a program can do. Say you get an e-mail with a program attatched. It's supposed to sing and dance. You should have check boxes that will not ever let this program sing and dance again, let it sing, but not let it create a window, or let it dance, but not make noise. By no means should this program be allowed to open files or network connections. Of course you could have a dumbed down version for the not so smart that says "This program wants to open windows and play music, do you want to allow this?" Then with the virus code tries to open a file or network connection or try to talk to the mail program, it will say "This program is trying to use your email/internet connection/open files on your disk... Should I let it?" Most users I think would be ok with this. If not, at least it could be configured in the ID-10T mode where they trust someone else to verify if a program is safe. Say you set up a computer for grannie in idiot mode. She gets all her trust from your certification server, and when she needs to run something you or a buddy hasn't tested to be ok, then she calls you and you add it for her. No more viruses for grandma. Then when sites are verified, no more (or a lot less) porn for children. It's all around a good deal if it's implemented properly.
I actually like the concept of trusted computing quite a bit. So long as the user selects which code will be trusted, it has great potential for good. My question is, from your position, do you foresee trusted computing being more like web-browser applet signing applied in hardware (where the user can add and remove trust for certain companies) or more like the media industries idea (where the OS/hardware manufacturers select which code is trusted under penalty of DMCA)?
I guess you have to apply the theory of the nature of relativity to see what I'm saying to begin with. In a phrase, it says we live in a ship in a bottle. Our perspective is distorted in order to make c a constant, and the speed of gravity~=c, the speed of light=c. From his other works, he says that light travels as both a particle and a wave (what doesn't?). The speed of light on the wave does not conform to his theory, but merely that the wave scrunches as to not travel in a ray faster than the speed of light. That's where I have to call BS. According to his own math, it should be impossible to achieve the speed of the photon along the wave. I could accept that it travels on a wave and the gravity isn't instant. This could account for the wave itself. This is a known problem with the theory of relativity, it doesn't apply on a small scale.
Now, since he assumed that nothing travels faster than the speed of light (but light itself does), his equations are going to be loaded. Lets say the speed of gravity is c-e^(-x). No matter what you put in x (as long as it's large), it's going to give you ~ c. I don't feel like looking up the real equations and spending a year playing with Einstein math to show it, but just for an example, it would take infinite energy to go the speed of light. Verticle assumtope's aren't hard to come up with.
More or less, what I'm saying is that the speed of the particle that feels the gravitational pull and it's mass will have to be used in the equation too, and that's going end up approximately cancelling out the speed and mass of Jupiter, leaving ~c in a relativistic equation. That's how relativity works.
A better experiment would have not used the theory of relativity to measure the speed of gravity. Measure the direction of the gravitational pull, and compare it to the direction of the light. The moon is ~500,000 miles away, and we can feel it's gravitational pull very easily.
yeah, you could use a ruler and a compass to confirm it, but he didn't.
No, the gravity wave experiment couldn't have gotten a value that far off if he conducted it properly. Explain how he could have?
I assume that Jupiter's mass and velocity are not in dispute? All he did is measure Jupiter's gravitational pull (I wonder how he accounted for enough of the other mass in the universe to get an accurate number). What formula did he then use to get the speed of gravity? According to the article, it was a formula from the theory of relativity. Since the theory was pretty clear that the speed of gravity is near c, I don't see how you could have a hard time seeing that it was obvious that he was going to get that number.
Besides, the best way to compare the speeds would have been to measure the angle between the direction of the pull and the direction of the light. Kind of like watching a plane fly over head. You see it in front of the source of it's sound.
So there, I have given you a great way to determine the speed of gravity relative to light without using relativity to calculate the speed of gravity. It's no more difficult to measure the angle to the source of the gravity than the gravitational pull(which he measured). If that shows that the speed of gravity is c, then he can use that to back the theory of relativity.
I just wished people would stop trying to prove their hypothesis with itself.
A ruler measures itself. That's what it does. You compare other objects to it to get their size. Don't be silly.
... and no, 10 inches is not a yard. ... and yes, you would be wrong to say it is.
My point exactly is that you need to know what a yard is first. You can't use the hypothesis to prove the hypothesis, else you would be right to call it a yard even though it's 10 inches.
He didn't measure the speed of gravity from what I can tell. He measured other variables then used equations from the theory of relativity to determine the speed of gravity. If that's not what he did, then he wouldn't have needed the theory of relativity to calculate the speed of gravity (the article said he did).
"He reworked the equations of general relativity to express the gravitational field of a moving body in terms of its mass, velocity and the speed of gravity. If you could measure the gravitational field of Jupiter, while knowing its mass and velocity, you could work out the speed of gravity."
Read it carefully. He used mass, velocity, and the gravitational field to measure the speed of gravity. So he measured mass, velocity, and the gravitational pull of Jupiter. He used the theory of relativity then to calculate the speed of gravity. If he didn't, I would like to see the formula that he did use and know where he found it.
You can't use the formulas of a hypothesis to gauge their accuracy against themselves. Einstein made those theories with the idea that gravity move at c. Therefore, any measurement you make, with his math, will make it look like c. It may be 2c, but if his math says that gravity is .5 it's actual speed, then after you take the .5, it will be c again.
The point is, his hypothesis was more like "the speed of gravity is c", and he used the theory of relativity to show that it is so. He makes it out like now that he has shown the speed of gravity to be c, it somehow strengthens the arguement for relativity. His original experiment assumed the theory of relativity, therefore, his findings are only as accurate as the theory of relativity. So, the speed of gravity being c is only as reliably as the theory of relativity. Therefore, when you use this to argue as a strength for the theory of relativity you end up with: The theory of relativity is only as reliable as the theory of relativity.
Absolutely correct definition of a theory, but incorrect definition of a evidence. Evidence can be in the form of an experiment, but only if the experiment is independant of the hypothesis. You can't say your ruler is a yard, then use it to measure itself as evidence that your ruler is a yard long.
At least I didn't assume the article was correct then use it to argue that the article was correct :)
If I assumed the world is flat, I could probably show that it has an edge. That doesn't mean that that the world is flat or round, because the premise of the experiment was flawed. If I assume the world is flat, and I have no proof, then I can only prove that my assumption is false. There is no evidence presented in his experiment that shows that the theory of relativity is true. In fact, his experiment doesn't grant one shred of knowledge. If you substitute a false equation into itself, you will still end up with a true statement. That sheds no light on the viability of the original statement one way or the other.
It showed that the speed of gravity was roughly c if you use calculations from a theory that assumes the speed of gravity is c.
No it shows absolutely nothing. It shows that if you assume GR, then a sub assumption of GR can be proven. If I use trig for a given, I better find PI~=3.14!
Let me put this into simple terms so you can understand.
He used principals of relativity to measure the speed of gravity. Relativity is still a theory with no means of being proven in the foreseeable future. Based on his unjustified assumption, he calculated the speed of gravity to conform to his assumption.
Ex) I say chickens lay square eggs, but the universe is warped to make them appear to be ovals. I make a mathmatical calculation to calculate the true form the the egg (a square) from the oval. What this guy did is assume that the eggs are square, then used my calculation to show that they are approximately square. Are the eggs really square?
According to the article:
"Isaac Newton thought the influence of gravity was instantaneous, but Einstein assumed it travelled at the speed of light and built this into his 1915 general theory of relativity."
According to the theory of relativity, nothing travels faster than the speed of light. Then again, gravity travels really fast. Therefore, gravity more than likely travels at near the speed of light.
"Kopeikin found another way. He reworked the equations of general relativity to express the gravitational field of a moving body in terms of its mass, velocity and the speed of gravity. If you could measure the gravitational field of Jupiter, while knowing its mass and velocity, you could work out the speed of gravity."
The theory of relativity was appearantly used to detect the speed of gravity. This would be fine if the theory of relativity didn't assume a speed of gravity. Basically, all he did was prove his given. So, if eggs are green, then eggs are green!
Nice post, but I have a little nit-picking :)
.Net on Windows?
MS has a porting tool that is supposed to work with 99% of all Java code. It probably won't work well with obscure API's or JNI, but I here it is indeed pretty magical. It makes the conversion process easy enough to play with for small apps. Larger apps will still take some grunt work I'm sure.
Swing is a nice GUI API, IMO. Like you though, it pains me too see GUI's written in Swing. Not because SWT is better, but because no one takes the time to use layouts properly. The end product is a GUI that looks and feels like VBA by a cheap contractor. I've seen good Swing applications, but they are as rare as good MS products. Maybe Luxor(XUL for Java) or one of it's kin will make UI design as easy as web design. Then only 50% of them will suck. The biggest problem with UI design in Java is that it's done by a programmer that only cares about functionality (a lot like me) and not by an artist (like the Mac UI). Swing isn't what makes apps slow. GC doesn't make Java slow. Poor programming habbits are the #1 cause of sluggish UIs.
With MS having to carry a decent JVM on the desktop now, you can expect to see a lot more apps for the desktop written in Java. If only SUN would lighten up on the license so it can be included on Linux....
An interesting side note: Since the judge ordered MS to carry Sun's JVM, does MS have to agree with the license for distrobution? Can they not ship competing technologies like J++ for
You can, and it doesn't have to be an American citizen that got it either. As long as the board members are in the US, you can bring them up on charges. They'll pin them on an Indian exec, but the company will have to hold it's head in shame from the publicity. That's why there are conspiracy crimes (conspiracy to commit murder etc.) and accessory crimes (even if they know what would happen, they are accessories since they have the power to stop it).
Surely there would be a simpler way of explaining how the speed of light could be constant. Even if there wasn't, I think it's nearly impossible to falsify. No matter what sane experiment people come up with that bends it, someone always claims it doesn't break it. If I said we all live in the Matrix, you may be able to bend my theory, but not break it. This is basically what the theory of relativity is. The theory of relativety says we live inside a warped universe. Our mass and our dimension changes depending on our speed. Which boarders contradiction of conservation of matter.
Then you have to consider that photons created by different orbitals are different wavelength. Where does that fit in to the theory? It's called different "energy" photons. This energy can't make the photon go faster, so it bounces more? Doesn't that make it go faster along the wave? If so, then does the theory mean you can't travel in a straight line faster than c? Then the theory falls apart for any peice of the wave.
The cesium chamber experiment alone proves that either the cesium chamber was moving at phenominal speeds without us seeing it, c ~ infinity, or the chamber is shorter than was measured. Some experiments actually get photons out before they go in. According to everything I've read about the theory, "all calculations of the speed of light will be the same to any observer." This clearly isn't true in the cesium condensate experiment.
Really now... Occam's Razor tells me that it would be much easier to believe that we can't measure the speed of light properly with our equipment, and it could be possible to travel faster than light. This is especially true considering that c is the speed of light in a ray at an ungiven wavelength instead of the speed of a photon along a wave.
There are more complications caused by the theory of relativity than those it sought to fix. I would rather go back to the original failures of the "classic" equations and fix whats wrong than fix a theory that seems to generate loop holes every month. It would be easier to scrap it and solve the original problems than make a patchwork theory.
Ok, If you don't say that the Pipeline allowed them to get 2x the clock speed (the fastest Athlon is 2.17 Ghz ATM), then I won't say that it hasn't let them crank out an extra 38% cycle speed.
If they catch branches early on (by the 5th stage), then they will not loose much performance. But because there are 10 instructions still not complete, it's unlikely they could catch the branch until all the instructions are complete and ready to write back to ram. Consider also the super scalar nature of the CPU. Now we are sitting around the 13th stage of the pipeline and we know which way to branch. If we were wrong, we loose 12*2=24 clock cycles. If branch prediction is 90% accurate(a stretch I would say) and code is about 10% branch statements, then 1 in every 100 instructions will cause you to loose 24 clock cycles. That's only branching! Now lets take that 20% of the time, the next instruction references the result of the current instruction. That usually causes the processor to insert NOPs into the pipe just after the decode until there is enough spacing between them so that the data can be forwarded to this instruction when it is ready for it's operands. In a normal pipe, that's only about 2 clock cycles. In a P4 pipe, that has to at least be 6. This is a factor or 3 slower about 20% of the time. That's about the same for branches. A good 1/3 of the cpu time is 3x slower on a P4. Sure you can compile around some of it, but that is just silly. That's why P4 introduced hyper threading that nothing is using. So instead of inserting NOPs, it can insert instructions from other programs that can't possibly reference the same data. That would be great, but it can be applied to shorter pipes just as well.
The majority of the performance increase of P4 has nothing to do with the pipeline. If the P4 was built on a normal pipeline, you could have expected to see a 2.2 Ghz machine right now that blew the AMD away.
Intel had a good chance with their Itanium to make a good RISC processor. A good load-store, 4/8 way super scalar, with a short pipeline, and it could still do 3Ghz easy. Instead, they decided to graft on the kitchen sink and a million other transistors that will lie dormant half the time. Most of the CPU will be sleeping even when you need it. I'm more excited about the new IBM processors for the mac.
A 50 stage pipeline wouldn't be bad if it were done differently. I still prefer the old "have one instruction after the branch that always is executed" method. Only with a longer pipeline, you would need more instructions. A good optimized compiler could handle this MUCH better than a processor could. Longer pipelines need better branch prediction. I don't really care about your research, because it's all theory. It's pretty appearant from comparing P3 to P4 that longer pipelines are only better if you can manage to crank out a factor of speed greater than the factor of increase in pipeline length. The whole "Software isn't compiled for P4 optimizations" arguement is really dumb when you think about it. If it can't run X86 faster, then it must really suck. In order to compensate for this, they have to run the P4 at much faster clock rates, and the compiled binaries have to be larger so as to place the jump points in strategic positions. Deeper pipelining will cause you to run into problems of silicon transistor switching speed much earlier than you would usually as well.
Rambus is a bad idea. It had very much inferior latency that increased with each memory module you add. The processor waits everytime you ask for ram. That's wasted cycles. There is a reason the P4 has an internal bus that is VERY wide compared to other processors. DDR's memory speed is in no way related to the bus's inferiority. The faster you make the chips, the faster the processor gets the data. With RAMBUS, you have additional latencies for the same speed of RAM. They are all made from the same DRAM design, and with the same speed chips, a wider bus will be faster.
I'm not upset that the Itanium changes instructions sets. I just don't think that any processor that disables part of itself will ever be optimal. I don't think lugging around old instruction sets are a good idea either. It's a waste of space that could have been used for some more full multipliers.
Don't take my word for it... go clock a P4 against another CPU and see how well it performs in sorting with RAMBUS memory. The bulk of the P4's gains on any other CPU comes from SSE2, 400Mhz FSB, and CPU clock speed. Take those away, and it will be slower per clock cycle than any other CPU (including P3), especially if it has RAMBUS memory.
Now everyone will know why the P4 sucks :) Honestly, in order to double the pipelines length, you really need to be twice as accurate with branch prediction, or else it will be slower per clock speed. It does make it easier for a chip to go faster, to a certain point, but the P4 is a bit excessive :) I just wonder sometimes if the Intel designers have ADD (think rambus (bad idea... memory width is a good thing!), P4 (don't increase the pipeline's length unless you have a good reason), Itanitium (scrap an entire architechture for one that allows you to disable instructions, so that it is gauranteed that part of the processor won't be used at that point)).
Something to combat md5sum itself from being cracked. Perhaps a statically compiled binary that you can download with the program of your choice. Then rootkits would have to modify every program that can download a file, or the kernel. The best system would be a nice bootable CD that would scan all known file system types for files that have md5 sums of known bad files, not search for files and make sure they have a md5 sum of a good file. Then root kits will have to rely on a compiler or append random bytes to the end of the files.
Well this gets so complicated that by the time you've thought it all out, you really need virus scanner technology to thwart root kits. Maybe a kernel patch could run a virus scan on executable files? It would be quite difficult to tamper with the actual running kernel in memory without causing the system to lock or reboot, thus giving away that the system is being tampered with. Assuming root kits are distributed in source form, you'll need heuristic scanning to find them. This means false positives and manual overides by the system administrator.
is helping the terrorists too... they just let anyone come in and purchase food. Those terrorists couldn't have made it to the planes if they had starved first! This will end terrorism because terrorists are too stupid to buy an AOL account!!!
This statement by the Dept. of Homeland Security was probably funded by AOL/Verizon/etc.
Don't forget --help / -h not talking about the configuration file, then man saying "This file/program has no man page, here is command -h, or see this website" When you go to the website, there is a FAQ, but no configuration example. Then the configuration path has to specified at compile time. Sometimes the configuration is stored in DB files in either TDB or BDB format of which there is no easy way to examine. Then you have to run make in some obscure directory on some programs to generate these files again from the text files. Then half the programs don't have a configuration reload option, but you just have to shut them down and restart them. If the new configuration is bad, it dies with an obscure error, or quietly. After digging through /var/log you might find some hint at where the problem is.
/etc could easily be replaced by one DB (LDAP-ish, but local) that is the registry and have a system library so all programs can access configurations in a standard way. I would prefer very much an editor that at least told me what I could set and had a range of values. Then it wouldn't require much to include a help database explaining each field's meaning. Parsing text that users write directly was never a good idea for configuration.
I can't believe that Linux people complain about the registry when they have this POS method for configuration. I'ld take the registry any day.
Then there is that god-aweful horrible X protocol. I don't care about all the third party support for it, it would be better to have a display that worked on one computer than one that half works on a million computers. I could run Win95 just fine on a 486 with 16M ram, but X would grind away at the hard disk for 10 minutes before it would start. I would rather have the Palm's GUI than any of the intrusive window managers out there. The one's that are clean require you to click through a menu 8 levels deep to find the program you want to run. I don't think users would be so opposed to pressing a hot key for a full screen menu with drag and drop support for their programs. I don't have to edit some hidden txt file under windows to change the menu. KDE lets you add icons to the desktop, and it lets you customize the menu, but it's really slow compared to any other OS's menus, and it's not very smart when it comes to clicking programs/files, because linux has "magic" instead of a good MIME typing system or extensions. XFS has support for adding attributes directly to the files, thus making it possible to store the MIME type with the file instead of as an extension, but no other file system supports it, thus there are no programs that do. This problem can be pinned directly on the linux kernel itself because the EXT filesystem s are the dumbest file systems since FAT. I thought it would be common sence to implement ACL's and Attributes, even more so if you aren't going to use brain-dead filename extensions.
The more I work with Linux to replace windows, the more I see the problems that arise from a million uncoordinated people hacking away at the same system. There is no consistency.
Are you a troll? ...lack of sse2... ...uses an astonishing amount of ram...64mb... ...unstable... ...only run at agp 2x...
It doesn't even run X86 natively!
64mb or ram costs 15$ The price difference between the P4 and the transmeta will easily be more than that. Buy more ram!
It hasn't even been released. Kernel 2.5 isn't all that stable, but no one complains because it is a testing/prototype.
The speed of the agp bus has been shown to be inconsequential to the performance.
The rumor is that the demo chip is running at 500Mhz at the moment. Comparing that to the 1.8ghz P4 suddenly doesn't seem so out of proportion does it? I gaurantee you it will be running at at least 1ghz when it's finally released. The final board for it (not the notoriously shoddy reference boards) will perform better as the memory bandwidth will probably be improved.
What if I had done the same review of the Itanium 6 mo. before it was released? It was running at 400Mhz, couldn't run X86 software as fast as a 266, and was practically an unstable toaster oven.
Try a different JVM if at all possible.. If not, you can configure the JVM to compile useing jikes. The problem you probably have is that the toy compiler that comes with the JDK that's written partially in java, turns out to leek memory (just enough to be annoying if you have a lot of JSPs). There are how-to's online for setting up jikes and tomcat. This issue has been known for a while, but SUN nor Tomcat feel like it's a big enough issue to get upset about. You could also have a look at Jetty which is faster than Tomcat and more stable and yet easier to set up.