On this basis C++ would be as fast a C. But we know it isn't really. What they have done is taken a C program and compiled it under the Java compiler, using little of the Java languages class features. You can do the same thing with C++ and get similar results.
But real world applications use objects extensively- we go to Java partly because it lets us do that (although there are other reasons, like added security.)
OK. I hear you say- why do you like it?
Well, it shows that if you really get stuck with a Java applications performance, it is often possible to redesign it to get C's level of speed.
And besides I love seeing the C++ lovers choking in their beers. (Java is as fast as C?! sppkkthth) - I get wet but its worth it.
Re:Satellite Internet? Big Deal
on
Iridium Saved?
·
· Score: 1
500 ms? You couldn't give 500ms latency telephony away. Iridium doesn't have 500ms latency.
Iridium isn't at GEO altitude- it's at 400km, (that's less than 1ms latency) That's also why it burns up in just a few years.
Hey, give him a break! He is, like, DEAD you know. I mean you can't get much more of a downer... Or maybe he already knows what the result is going to be, being dead and all... Uh oh. Its an omen.
That won't last. I heard about someone researching the 'worlds most inaccessible tribe'. They couldn't find much info on it, until someone suggested they look it up on the web.
They found quite a bit of information actually. Turns out they had a web page, together with a picture of their new helipad;-)
Basically it might be possible, contrary to popular belief. But there's no certainty either way.
The big problem with chess is that the tree is VERY large- how big isn't known but estimates vary over a large range (see netchess and wolfram mathworld). There are certainly more chess positions than there are atoms in the universe, but the lines that lead to them are mostly worthless, so they don't matter and can be pruned away. Let's pick a tree size of 10^60-10^70 for arguments sake.
This is way beyond the scope of even distributed computing like SETI. It's usually reckoned that chess is unsolvable by brute force.
Normal computer techniques can handle about trees with about 10^20 positions or so, depending on how much hardware you can throw at it, and how long you wait.
However there are a couple of approaches that can reduce the exponent by a factor of 2 each in chess:
Use both and the search tree comes down from 10^70 to 10^17. That is still a HUGE tree, but it is searchable in a year using a quantum computer that can search 3 billion positions a second.
As another poster noted, the current state of the art is 7 bits. You would need probably need 100s of thousands of bits to do chess. And the cycle time for current computers are measured in seconds rather than nanoseconds, but then again no optimisation for speed has been done AFAIK.
Finally it depends on the actual size of the chess tree. It may very well be there is a forced checkmate at say, move 40, in which case we would find it. But if there are only draws by repetition, under perfect play, the tree probably becomes impossibly large even with quantum computers.
Still, a search that said that there were no forced wins in say, the first 40 moves would be suggestive of a draw.
The fruit flies that I know seem to be missing their GPL, but we'll let them off I guess. Besides, they don't seem to have any money so there's no point in suing.
Quantum computing, on paper, although not in the lab yet, can factorise numbers much quicker than conventional methods.
How much faster? Well if conventional techniques need 2^64 operations to factor something, QC needs 2^32 to do the same thing. Therefore, to regain the same level of security you would have to double the length of the keys you use. This isn't particularly difficult (encryption and decryption would run more than twice as slowly, but Moore's law soon sorts that out.)
NO NEW SCHEMES ARE REQUIRED! (well mostly...)
If you want to know more, do a google search, there's a large range of articles on it.
I have. Gas pumps used to be mechanical. Then they switched over to computerised displays and computer controlled measuring systems that report back to the interior checkout.
Trouble is they weren't well EMC shielded. So along comes the hacker, with an illegally powerful ham radio.
He gets halfway through filling and: ZAP! - with luck, the pump will stop registering anymore fuel.
Before you rush out to try it, it doesn't work very well anymore. The shielding is much better.
Sure this isn't a software hack, but if it puts a military vehicle out of action it doesn't really matter. Also, theoretically it might in fact be possible to reprogram something remotely (even if the wires to do it have been cut, if you put the right voltages on it, its going to work;-)
- that someone trying to solve it, doesn't prove that it is impossible to prove.
(No i'm not trolling- in maths it really is sometimes possible to write a proof that something else can't be proven... for example there's no general equation to find the solutions to a 5th order equation, that was proven.)
In that case presumably they wouldn't pay up... would that suck or what?;-)
The problem with mars is that theres no obvious way to make money.
I think we should first mine Eros (that's a near earth asteroid.) Estimates indicate that it has 20 TRILLION dollars of ore on it- its 3% metal! It has everything, gold, plutonium, platinum...
There's nothing wrong with money. Money makes the satellites go around, and the sort of capabilities that you need to mine Eros will help get to mars- and probably pay for it.
And besides we need need to be able to stop the next dinosaur killer asteroid... living on Mars won't help much with that. Chucking around lumps of asteroid will.
As to your argument that problems can occur in C/C++ code. I concur. That's why its important to write as much of the system as possible in Java.
Ultimately more code, quicker is always going to win. C++ is terribly UNproductive. C is better but less powerful. Java is more powerful than C and more productive.
About the only technology that stands any chance at all is Java/Java Platform from Sun microsystems. The Java Platform is an operating system in every real sense of the word. The current problems with the Java Platform that are roadblocks to this happening are: a) Java's performance (its a bit, NOT a lot slower, then again C is a bit slower than assembler- but who cares?) b) its semi-proprietary The main drivers that are making it happen are: a) Java distributes real well b) hacking Java is a lot easier, quicker than hacking C/C++ that is mostly used for Unix c) Java is more reliable (although a lot of JVMs might make you doubt that!) d) Java interworks with lots of things- its a survivor Of course in many current situations it is run on top of another operating system, but there is no necessity for that. Java doesn't need Unix to be there at all. The converse may not be true for long... Still, prediction is always difficult. Especially about the future. (Thanks Woody)
At present you might get one per day, how do you feel about 16 per day? Wait 3 years... 32? Wait another 9 months.
Don't believe me? The internet is doubling in size, what, every 9 months? The biggest argument against spam is that it doesn't scale well.
Twice as many people means twice as many spammers. Assuming it doesn't get to be a more popular per user.
What can you do? Get your local politicians email addresses. Add them to every distribution list you can find. Wait for the law to arrive. (Both the cops for you and the legislation for the country.)
Nice try. But that isn't the proposal. The proposal IS:
1. solar-electric panels in space (not mirrors)
2. microwave transmission (20% loss experimentally, not 50%)
3. Much bigger area is possible in space (that's why its called space, like duh-huh; where were you planning to get the land from on the earth anyhow? How much was this supposed to cost? Earth solar panels aren't competitive at ALL.)
4. 24 hour availability in space (you can't use solar panels on the earth mostly because you can't rely on the power- I'm sorry we can't connect you to the internet today because it is cloudy. Please try again.)
5. No seasonal variation. Try heating and lighting your house in february using solar power, in the UK. If you have double glazing, make sure you include the costs of energy to make the windows...
6. Zero pollution. By the time you've accounted for the pollution and paid for the replacement cost of fossil fuels- it no longer looks very cheap at all (and we are running out of oil rather). In space no pollution. Nahda. Zip. Zilch. None.
Other advantages include: moveable generators (try doing THAT on the earth, wonder if China could do with an extra powerstation right now? How about India?), cheaper processing of materials. Probably cheaper EVERYTHING, once you're up there. Getting up there costs $2600/lb right now, and its on the way down...
Finally, you mentioned current rates of increase of power- I hope you don't live in California;-)
Actually space is already a 50 billion a year industry and growing at a decent rate (15% per annum).
There's starting to be some decent competition, and provided nothing screws up to stop that the costs to enter space have dropped and are likely to continue to drop (it currently costs $1300/lb to get to low earth orbit for freight, man-rated is 10x that.).
We may be looking at half that cost in 5-10 years assuming nothing much happens. If something dramatic happens like a new launcher then we are looking at one or more order of magnitude reduction in cost even with an expendable launching system.
You can bet that when the costs to launch get low enough, the amount of money that there is floating around in space is going to attract some funding. (Asteroids appear to be able to sustain a population of 100s of trillions.)
Even solar powered satellites have some massive environmental advantages. They are totally non polluting for one thing... A government can get some useful political capital by being seen to support it. Environmentalism is a growing force in this world.
Microwave power beaming down to the earth existed then, was and is workable. Also the one thing that Solar Power Satellites is, is environmentally friendly. In fact it is almost certainly the most environmentally friendly power supply ever invented.
Nuclear fusion is 50 years away. And has been for the last 50 years. And probably will be in another 50 years.
And even if it weren't, nuclear fusion is every bit as dirty as nuclear fission. In fact just about the only known practical way to make energy from controlled nuclear fusion is to use nuclear fusion to irradiate material- make it radioactive and feed it into a fission reactor!
If you add up the amount of money spent on nuclear fusion over the last 50 years, we could have had a high frontier by now...
>Most people care about the per node latency - establishing new paths through the
>network is often done by management systems only, and can take tens of milliseconds
>upwards, particularly if it's not required for resilience to failure.
You, in turn, seem to be confusing two concepts in one sentence here: setting up new paths through the network (which doesn't have to be particularly fast at the moment for SONET- tens of SECONDS is possibly acceptable although not desirable) and the 'switching time' of 32 microseconds or less per node which seems adequate bearing in mind the approximately fractal nature of the internet tends to restrict the hop count.
Slashdot Mirror
But real world applications use objects extensively- we go to Java partly because it lets us do that (although there are other reasons, like added security.)
OK. I hear you say- why do you like it?
Well, it shows that if you really get stuck with a Java applications performance, it is often possible to redesign it to get C's level of speed.
And besides I love seeing the C++ lovers choking in their beers. (Java is as fast as C?! sppkkthth) - I get wet but its worth it.
Iridium isn't at GEO altitude- it's at 400km, (that's less than 1ms latency) That's also why it burns up in just a few years.
Hey, give him a break! He is, like, DEAD you know. I mean you can't get much more of a downer... Or maybe he already knows what the result is going to be, being dead and all... Uh oh. Its an omen.
They found quite a bit of information actually. Turns out they had a web page, together with a picture of their new helipad ;-)
The big problem with chess is that the tree is VERY large- how big isn't known but estimates vary over a large range (see netchess and wolfram mathworld). There are certainly more chess positions than there are atoms in the universe, but the lines that lead to them are mostly worthless, so they don't matter and can be pruned away. Let's pick a tree size of 10^60-10^70 for arguments sake.
This is way beyond the scope of even distributed computing like SETI. It's usually reckoned that chess is unsolvable by brute force.
Normal computer techniques can handle about trees with about 10^20 positions or so, depending on how much hardware you can throw at it, and how long you wait.
However there are a couple of approaches that can reduce the exponent by a factor of 2 each in chess:
- Quantum computing
- Alpha-Beta pruning
Use both and the search tree comes down from 10^70 to 10^17. That is still a HUGE tree, but it is searchable in a year using a quantum computer that can search 3 billion positions a second.As another poster noted, the current state of the art is 7 bits. You would need probably need 100s of thousands of bits to do chess. And the cycle time for current computers are measured in seconds rather than nanoseconds, but then again no optimisation for speed has been done AFAIK.
Finally it depends on the actual size of the chess tree. It may very well be there is a forced checkmate at say, move 40, in which case we would find it. But if there are only draws by repetition, under perfect play, the tree probably becomes impossibly large even with quantum computers.
Still, a search that said that there were no forced wins in say, the first 40 moves would be suggestive of a draw.
Yeah, and we share about 60% of the same genes as a banana ;-)
Maybe that's in the next release or something?
How much faster? Well if conventional techniques need 2^64 operations to factor something, QC needs 2^32 to do the same thing. Therefore, to regain the same level of security you would have to double the length of the keys you use. This isn't particularly difficult (encryption and decryption would run more than twice as slowly, but Moore's law soon sorts that out.)
NO NEW SCHEMES ARE REQUIRED! (well mostly...)
If you want to know more, do a google search, there's a large range of articles on it.
Trouble is they weren't well EMC shielded. So along comes the hacker, with an illegally powerful ham radio.
He gets halfway through filling and: ZAP! - with luck, the pump will stop registering anymore fuel.
Before you rush out to try it, it doesn't work very well anymore. The shielding is much better.
Sure this isn't a software hack, but if it puts a military vehicle out of action it doesn't really matter. Also, theoretically it might in fact be possible to reprogram something remotely (even if the wires to do it have been cut, if you put the right voltages on it, its going to work ;-)
(No i'm not trolling- in maths it really is sometimes possible to write a proof that something else can't be proven... for example there's no general equation to find the solutions to a 5th order equation, that was proven.)
In that case presumably they wouldn't pay up... would that suck or what? ;-)
I think we should first mine Eros (that's a near earth asteroid.) Estimates indicate that it has 20 TRILLION dollars of ore on it- its 3% metal! It has everything, gold, plutonium, platinum...
There's nothing wrong with money. Money makes the satellites go around, and the sort of capabilities that you need to mine Eros will help get to mars- and probably pay for it.
And besides we need need to be able to stop the next dinosaur killer asteroid... living on Mars won't help much with that. Chucking around lumps of asteroid will.
The whole idea is that the native operating system is going to be the JVM. You don't put the JVM on the native OS. It can BE the native OS.
JVMs have:
- memory management
- thread handling (inc. semaphores)
- file handling
- graphics interfaces
- printing
- message handling
i.e. its an OS.
As to your argument that problems can occur in C/C++ code. I concur. That's why its important to write as much of the system as possible in Java.
Ultimately more code, quicker is always going to win. C++ is terribly UNproductive. C is better but less powerful. Java is more powerful than C and more productive.
About the only technology that stands any chance at all is Java/Java Platform from Sun microsystems. The Java Platform is an operating system in every real sense of the word. The current problems with the Java Platform that are roadblocks to this happening are: a) Java's performance (its a bit, NOT a lot slower, then again C is a bit slower than assembler- but who cares?) b) its semi-proprietary The main drivers that are making it happen are: a) Java distributes real well b) hacking Java is a lot easier, quicker than hacking C/C++ that is mostly used for Unix c) Java is more reliable (although a lot of JVMs might make you doubt that!) d) Java interworks with lots of things- its a survivor Of course in many current situations it is run on top of another operating system, but there is no necessity for that. Java doesn't need Unix to be there at all. The converse may not be true for long... Still, prediction is always difficult. Especially about the future. (Thanks Woody)
Don't believe me? The internet is doubling in size, what, every 9 months? The biggest argument against spam is that it doesn't scale well.
Twice as many people means twice as many spammers. Assuming it doesn't get to be a more popular per user.
What can you do? Get your local politicians email addresses. Add them to every distribution list you can find. Wait for the law to arrive. (Both the cops for you and the legislation for the country.)
Nice try. But that isn't the proposal. The proposal IS:
;-)
1. solar-electric panels in space (not mirrors)
2. microwave transmission (20% loss experimentally, not 50%)
3. Much bigger area is possible in space (that's why its called space, like duh-huh; where were you planning to get the land from on the earth anyhow? How much was this supposed to cost? Earth solar panels aren't competitive at ALL.)
4. 24 hour availability in space (you can't use solar panels on the earth mostly because you can't rely on the power- I'm sorry we can't connect you to the internet today because it is cloudy. Please try again.)
5. No seasonal variation. Try heating and lighting your house in february using solar power, in the UK. If you have double glazing, make sure you include the costs of energy to make the windows...
6. Zero pollution. By the time you've accounted for the pollution and paid for the replacement cost of fossil fuels- it no longer looks very cheap at all (and we are running out of oil rather). In space no pollution. Nahda. Zip. Zilch. None.
Other advantages include: moveable generators (try doing THAT on the earth, wonder if China could do with an extra powerstation right now? How about India?), cheaper processing of materials. Probably cheaper EVERYTHING, once you're up there. Getting up there costs $2600/lb right now, and its on the way down...
Finally, you mentioned current rates of increase of power- I hope you don't live in California
Actually space is already a 50 billion a year industry and growing at a decent rate (15% per annum).
There's starting to be some decent competition, and provided nothing screws up to stop that the costs to enter space have dropped and are likely to continue to drop (it currently costs $1300/lb to get to low earth orbit for freight, man-rated is 10x that.).
We may be looking at half that cost in 5-10 years assuming nothing much happens. If something dramatic happens like a new launcher then we are looking at one or more order of magnitude reduction in cost even with an expendable launching system.
You can bet that when the costs to launch get low enough, the amount of money that there is floating around in space is going to attract some funding. (Asteroids appear to be able to sustain a population of 100s of trillions.)
Even solar powered satellites have some massive environmental advantages. They are totally non polluting for one thing... A government can get some useful political capital by being seen to support it. Environmentalism is a growing force in this world.
Microwave power beaming down to the earth existed then, was and is workable. Also the one thing that Solar Power Satellites is, is environmentally friendly. In fact it is almost certainly the most environmentally friendly power supply ever invented.
Nuclear fusion is 50 years away. And has been for the last 50 years. And probably will be in another 50 years.
And even if it weren't, nuclear fusion is every bit as dirty as nuclear fission. In fact just about the only known practical way to make energy from controlled nuclear fusion is to use nuclear fusion to irradiate material- make it radioactive and feed it into a fission reactor!
If you add up the amount of money spent on nuclear fusion over the last 50 years, we could have had a high frontier by now...
>Most people care about the per node latency - establishing new paths through the
>network is often done by management systems only, and can take tens of milliseconds
>upwards, particularly if it's not required for resilience to failure.
You, in turn, seem to be confusing two concepts in one sentence here: setting up new paths through the network (which doesn't have to be particularly fast at the moment for SONET- tens of SECONDS is possibly acceptable although not desirable) and the 'switching time' of 32 microseconds or less per node which seems adequate bearing in mind the approximately fractal nature of the internet tends to restrict the hop count.