The energy to compress and cool the N2 is not free.
No, but I don't see that as the point. The purpose of using N2 should be to use it as a kind of "battery" - as a means of storing the energy in the car until you step on the gas pedal.
I just wonder how effecient this is? How many GJ can you store per liter of N2? I would guess that storing the energy as H2 for later burning is much more efficient (I once heard something about 90% efficiency in the produce-consume cycle of H2!).
Just a minor point: You don't use energy to cool the N2 when bootling it - rather, when putting it under great pressure, it is heated. After compression, this heat (energy) is slowly delivered to the atmosphere until the N2 has atmosphere temperature. And actually, that very same heat energy is taken back "out of the air" when you consume the energy stored in the N2 bottle!
Excuse my ignorance (my physics courses are far far away), but since heat is basically the free agitation of
molecules, why coulnd't a device get energy from this agitation by slowing down molecules and getting the excess
energy somewhere else ?
This is about entropy. You cannot lower the "global" entropy. So in order to cool the energy-rich hot molecules (thereby decreasing its entropy) you have to heat up something else. Thermo dynamics calculations will show that you cannot take the energy out of a warm material without turning most of that energy into heat somewhere else (only most: the small difference is the energy you gain by taking back the energy you used in the fridge to seperate hot and cold air). I guess the short answer to your question is that devices are "too clumsy" to make energy out of slowing down the molecules - the atoms of our device would smash into the molecules that we were supposed to slow down.
Is there any reason (theoretical or otherwise) for the lack of a processor/architecture which more closely corresponds to the functional way of programming?
Well, a computer works in a very imperative fashion - just look at it: the disk arm moves, things are written to disk (destructive update), the RAM has a **state**. It is all state and actions, and there's nothing to do about that. In the end, the world is imperative in its nature.
My conclusion is that every (re)implementation of the digital computer will only give a constant speedup for functional programs. That constant might be high, and is worth going for. The way of supporting functional programs in a CPU would probably be to have hardware support for some of the common operations at the low level of the implementation of the "runtime machine" that runs the program. Such operations could be handling closures (thunks), hardware support for garbage collection (maybe implicit ref-counting).
So the answer is yes and no: You cannot implement a "functional computer", since any (real world) computer is implemented on top of (real world) physics, but you could have CPU instructions/architecture better suited for execution of functional programs (speedup by a large factor).
I think SETI appeals to a certain type of people that like the idea of parallel processing, like shiny dynamic graphics, aliens, computers and whatnot. Plus give them the biggest incentive of all: Number scores! Get the most SETI points, get ranked, Hell, I'm whoring for Karma right now!
Exactly! I think that this is the #1 reason for participating in a distributed project.
Think about all the geeks, who have spent weeks on tuning their computer, overclocking and whatnot. Now they finally get a chance to prove that they are Real Men with Real Computers that kick some ass. What else are they going to use those giga-flops for?
Does your employer disagree with you on many things, among them your identation style, OR does everyone disagree with your indentation style, including your employer?
Although English is not my first language -- in the last case, wouldn't it be "Disclaimer: Even my employer doesn't agree with me about C indentation style"?
An then I guess you missed: "My employer doesn't do a lot of things with me about the C indentation style. Agreeing is one of the thing he doesn't do with me".
I mean I realise the open source community is fantastic but there is still no requirement for companies to open source things.
At the end of the day, i'd guess, your company is in business to make money and I dont entirely see why you should be so keen to open source something if your livelyhoods depend on it.
I agree that if the customers are happy with closed-source, then don't go open-source.
But maybe the question here is not so much "Why should a company go open source?" as it is "Why should the customers be satisfied with anything less than OpenSource?".
I personally would prefer a company that was confident enough in its software to close the source and charge for it. If the coder is so desperate for customers that he has to give it away and ride the coattails of open source fever, I would be suspicious.
There's absolutely no reason to believe that closed-source products are from companies that produces better code. Rather the opposite: By open-sourcing, you are revealing all the nasty hacks in the code, if any. So, companies doing quick-n-dirty programming cannot go open-source.
So staying closed source IMHO doesn't indicate that the company is confident in its software, rather that they are unconfortable with other people seing how crappy their product really is.
Maybe not in theory, but there exists devices that for all practical purposes is tamper resistant. I once worked on a software product using an IBM4758, a cryptographical device that can keep a private RSA key very private. It detects abnormal input voltage, too high temperature, X-rays, physical intrusion, and whatnot. My impression is that nobody in the world can get the private key out of the device.
By the way: the device has two batteries to keep the keys in RAM. If you would like to keep your precious keys, you are supposed to change the batteries only one at a time. Suddenly, a stable 1,5V can be worth a lot!!;-)
With a built-in D/A-converter, such a device could protect music from being digitally copied. The real problem for the music industry is a practical one, though - someone has to put the private key into the device. As long as a few people has access to the information about how to do that, it's no longer a secret. Sooner or later, the key will be public.
Let's see how long it will take the industry to figure out that they cannot copy protect music without preventing the costumers from listening to it.
There are a trillion neurons in a mammalian brain with a thousand connections each. It will take a while to emulate this.
I think the real problem is not the massive size (even though it's far from trivial). Simulating a trillion nodes should be within realistic reach, if enough money were thrown after it. One thing that helps is that NN's are very fault tolerant (Killing a whole area of cells doens't matter THAT much in the human brain). Here's one (far-fetched) idea of how this fact could be utilized in the ANN production: The factory could maybe almost put (electonic/chemic/whatever) neurons on a spray can, spraying it all over the chip surface, not worrying too much about how many are not well-connected, and not being able to control the detailed connectivity that fine-grained;-). An initial bootstrapping (applying some chemical?) should tell the cells to explore the environment they were put in (chat with their neighbors), committing suicide if they were badly connected. Also, this bootstrapping chemical should cause the nodes to build "power choords" to themselves. And so what if only 50% survives this "spread of the cells"? The key to this is just that interconnectivity and quantity might not have to be that precise (as for example in a CPU) - just spray the neurons out there.
Okay, so the quantity of this problem could maybe be solved. What I think is the real problem is the programming. Brain scientists have almost no idea how the brain works and learns. And even if we found out an effective way to train the artificial brain, there's an even worse problem: The human brain is so preprogrammed that we wouldn't believe it. How on earth should we capture all the preprogrammed information and behaviour in the human brain, short of emulating real neurons (only the simpler artificial ones)...
Most comments on this story are about search for E.T.
Have you read the article? I find nothing indicating that search for extraterrestial life is the intend of keeping those frequencies clear.
It's about radio astronomy. To me, that means exploring the space, the stars, the galaxies, etc.
Some comments indicate that we shouln't explore farther away than our solar system, because we will never go longer anyway... I think you totally miss the point of atronomy. It's not about "preparing a trip to mars", it's rather about exploring the world we live in - find out how things are, how nature works, and so on. The best and most useful results of science are often those of research that didn't have any really practical purpurse, but that is rather based on curiosity.
While the more practical research is about finding "the answers", you could say that real research is about finding the relevant questions to ask.
(I'm not an astronomer - although a Physics minor and Mathematics major.)
There needs to be something similar for Linux. Although companies that ship Linux have the sense of decency not to inforce spyware, times are changing.
On Linux we have strace(1). It can show you any system call performed by the program. That should make it easy to spot unwarranted network connections, opening of files, etc.
C++ implements very static types -- something which has been loosened a bit by the introduction of RTTI.
On the other hand, part of Java's success (I hate myself for bringing the J-word into the question;-) must come from the need of interchanging code as well as data on the internet -- something which requires the very opposite: dynamic types, or at least, dynamically loadable types.
The question: Could it be possible to have dynamic types as "first class" types in an extended C++, or would that interfere too much with the basic design principles? What would be needed of the runtime environment?
Another question: I've seen you often quoted that Java was not the language you would have designed, were C-compatibility not an issue. So which parts of C would you be most glad to see disappear from C++, if compatibility was not an issue? Would the basic types be objects with primitive "member functions", i.e. would the language be what is called purely object oriented?
Whether people want electric cars or not is IMHO not about economy or environment. People want a car that they think sound like a car and smell like one, too.
Also, the reason why people doesn't use public transportation, even when it's faster, is that they want to sit in their own car and pick their noses and fart, and whatnot.;-)
Until we understand these kinds of strangenesses that car-owners have, we're not in a good position to convince them to buy an electric car.;-)
Slashdot Mirror
No, but I don't see that as the point. The purpose of using N2 should be to use it as a kind of "battery" - as a means of storing the energy in the car until you step on the gas pedal.
I just wonder how effecient this is? How many GJ can you store per liter of N2? I would guess that storing the energy as H2 for later burning is much more efficient (I once heard something about 90% efficiency in the produce-consume cycle of H2!).
Just a minor point: You don't use energy to cool the N2 when bootling it - rather, when putting it under great pressure, it is heated. After compression, this heat (energy) is slowly delivered to the atmosphere until the N2 has atmosphere temperature. And actually, that very same heat energy is taken back "out of the air" when you consume the energy stored in the N2 bottle!
This is about entropy. You cannot lower the "global" entropy. So in order to cool the energy-rich hot molecules (thereby decreasing its entropy) you have to heat up something else. Thermo dynamics calculations will show that you cannot take the energy out of a warm material without turning most of that energy into heat somewhere else (only most: the small difference is the energy you gain by taking back the energy you used in the fridge to seperate hot and cold air). I guess the short answer to your question is that devices are "too clumsy" to make energy out of slowing down the molecules - the atoms of our device would smash into the molecules that we were supposed to slow down.
Well, a computer works in a very imperative fashion - just look at it: the disk arm moves, things are written to disk (destructive update), the RAM has a **state**. It is all state and actions, and there's nothing to do about that. In the end, the world is imperative in its nature.
My conclusion is that every (re)implementation of the digital computer will only give a constant speedup for functional programs. That constant might be high, and is worth going for.
The way of supporting functional programs in a CPU would probably be to have hardware support for some of the common operations at the low level of the implementation of the "runtime machine" that runs the program. Such operations could be handling closures (thunks), hardware support for garbage collection (maybe implicit ref-counting).
So the answer is yes and no: You cannot implement a "functional computer", since any (real world) computer is implemented on top of (real world) physics, but you could have CPU instructions/architecture better suited for execution of functional programs (speedup by a large factor).
Exactly! I think that this is the #1 reason for participating in a distributed project.
Think about all the geeks, who have spent weeks on tuning their computer, overclocking and whatnot. Now they finally get a chance to prove that they are Real Men with Real Computers that kick some ass. What else are they going to use those giga-flops for?
OR
does everyone disagree with your indentation style, including your employer?
Although English is not my first language -- in the last case, wouldn't it be "Disclaimer: Even my employer doesn't agree with me about C indentation style"?
An then I guess you missed: "My employer doesn't do a lot of things with me about the C indentation style. Agreeing is one of the thing he doesn't do with me".
Moderators: -1, Off topic
At the end of the day, i'd guess, your company is in business to make money and I dont entirely see why you should be so keen to open source something if your livelyhoods depend on it.
I agree that if the customers are happy with closed-source, then don't go open-source.
But maybe the question here is not so much "Why should a company go open source?" as it is "Why should the customers be satisfied with anything less than OpenSource?".
There's absolutely no reason to believe that closed-source products are from companies that produces better code. Rather the opposite: By open-sourcing, you are revealing all the nasty hacks in the code, if any. So, companies doing quick-n-dirty programming cannot go open-source.
So staying closed source IMHO doesn't indicate that the company is confident in its software, rather that they are unconfortable with other people seing how crappy their product really is.
Maybe not in theory, but there exists devices that for all practical purposes is tamper resistant. I once worked on a software product using an IBM4758, a cryptographical device that can keep a private RSA key very private. It detects abnormal input voltage, too high temperature, X-rays, physical intrusion, and whatnot.
My impression is that nobody in the world can get the private key out of the device.
By the way: the device has two batteries to keep the keys in RAM. If you would like to keep your precious keys, you are supposed to change the batteries only one at a time. Suddenly, a stable 1,5V can be worth a lot!! ;-)
With a built-in D/A-converter, such a device could protect music from being digitally copied. The real problem for the music industry is a practical one, though - someone has to put the private key into the device. As long as a few people has access to the information about how to do that, it's no longer a secret. Sooner or later, the key will be public.
Let's see how long it will take the industry to figure out that they cannot copy protect music without preventing the costumers from listening to it.
I think the real problem is not the massive size (even though it's far from trivial). Simulating a trillion nodes should be within realistic reach, if enough money were thrown after it. One thing that helps is that NN's are very fault tolerant (Killing a whole area of cells doens't matter THAT much in the human brain). ;-). An initial bootstrapping (applying some chemical?) should tell the cells to explore the environment they were put in (chat with their neighbors), committing suicide if they were badly connected. Also, this bootstrapping chemical should cause the nodes to build "power choords" to themselves. And so what if only 50% survives this "spread of the cells"?
Here's one (far-fetched) idea of how this fact could be utilized in the ANN production: The factory could maybe almost put (electonic/chemic/whatever) neurons on a spray can, spraying it all over the chip surface, not worrying too much about how many are not well-connected, and not being able to control the detailed connectivity that fine-grained
The key to this is just that interconnectivity and quantity might not have to be that precise (as for example in a CPU) - just spray the neurons out there.
Okay, so the quantity of this problem could maybe be solved.
What I think is the real problem is the programming. Brain scientists have almost no idea how the brain works and learns. And even if we found out an effective way to train the artificial brain, there's an even worse problem: The human brain is so preprogrammed that we wouldn't believe it. How on earth should we capture all the preprogrammed information and behaviour in the human brain, short of emulating real neurons (only the simpler artificial ones)...
Have you read the article? I find nothing indicating that search for extraterrestial life is the intend of keeping those frequencies clear.
It's about radio astronomy. To me, that means exploring the space, the stars, the galaxies, etc.
Some comments indicate that we shouln't explore farther away than our solar system, because we will never go longer anyway... I think you totally miss the point of atronomy. It's not about "preparing a trip to mars", it's rather about exploring the world we live in - find out how things are, how nature works, and so on. The best and most useful results of science are often those of research that didn't have any really practical purpurse, but that is rather based on curiosity.
While the more practical research is about finding "the answers", you could say that real research is about finding the relevant questions to ask.
(I'm not an astronomer - although a Physics minor and Mathematics major.)
On Linux we have strace(1). It can show you any system call performed by the program. That should make it easy to spot unwarranted network connections, opening of files, etc.
C++ implements very static types -- something which has been loosened a bit by the introduction of RTTI.
On the other hand, part of Java's success (I hate myself for bringing the J-word into the question ;-) must come from the need of interchanging code as well as data on the internet -- something which requires the very opposite: dynamic types, or at least, dynamically loadable types.
The question:
Could it be possible to have dynamic types as "first class" types in an extended C++, or would that interfere too much with the basic design principles? What would be needed of the runtime environment?
Another question: I've seen you often quoted that Java was not the language you would have designed, were C-compatibility not an issue. So which parts of C would you be most glad to see disappear from C++, if compatibility was not an issue? Would the basic types be objects with primitive "member functions", i.e. would the language be what is called purely object oriented?
Also, the reason why people doesn't use public transportation, even when it's faster, is that they want to sit in their own car and pick their noses and fart, and whatnot. ;-)
Until we understand these kinds of strangenesses that car-owners have, we're not in a good position to convince them to buy an electric car. ;-)