a) don't have to pay per use of the roads (mostly)
b) don't have guaranteed quality of service (traffic jams)
c) can't make money from the roads (unless you are a roadbuilder)
d) some people make money shipping stuff around though
e) some people make money building stuff to use the roads
f) some people make very small amount of money telling you were to find things (map makers)
g) roads cost tax money to build and run, yet don't directly make ANY money!
Yeah, and the people who pay for the roads don't usually make money back from them! All these roads are therefore a commercial failure, and we need to privatise all of them so that businesses can make money. It's obvious! How could I have missed it?
That's what RSVP in IPv6 gives you. They 'reserve' some bandwidth for high priority traffic. If it doesn't get used then it gets filled with casual traffic, web browsing, ftp, mail etc. VOIP and Videophone/Quake IV stuff gets first dibs.
Uh? Quake IV? Is that important? Well, you will probably have a quota of high priority traffic, (say, only 1/10 of your bandwidth allowed to be high priority), and then you have to pay extra after that. So Quake IV doesn't use much bandwidth, so would fit inside your quota.
Impossible? I don't think so. All you have to do is each time somebody receives a junk email they mark it as junk email, the mail software can calculate one checksum starting at a random place in the file, and upload it to a checksum server. For any frequently received junk email the server will fairly quickly get enough checksums that the whole document will be covered.
When anybody receives an email, they can check a handful of random checksums against the checksum server, if enough of them match, then do a few more to be sure and deal with the email according to any settings by the user.
Still, there are issues. What happens if the email marketeers start appending random web pages to their email to dilute it down? What percentage of similarity is enough? There are some fixes- I think to be successful junk mail has to be fairly short- people rarely page down to cut to the chase; but adjusting the checksum points to emphasise the beginning and end of the email is probably a good thing.
>Aren't there algorithms that will report messages that are pretty close?
Yeah, there are. 'Rdist' does this as a way of trying to only send the minimum set of changes necessary to keep two ftp/web sites synchronised.
Actually to be precise, the checksum isn't imprecise, as rdist relies on checksums of subsets of the documents they are trying to synchronise.
This neatly sidesteps the counter issue...
The big issue is counters and other subtle changes to the emails that would destroy a naive checksum.
However multiple checksums of subsets of the email would not usually all be changed by one or a few changes/counters and checksums will be sufficiently discriminating to screen emails and can do a very good jobs of detecting any widespread junk emails.
It would be difficult that all checksums of all characters of a particular length (say 20 characters) be made sufficiently different that ALL of the subsets of the junk emails can be different.
(Checksums that checksum all the strings for a particular length are not difficult to generate as a matter of fact; little more than a circular buffer is required.)
IRC Helium-3 isn't very common. Where you gonna get it from?
Secondly, how easily does D-3He fuse? It takes a MUCH higher temperature and pressure doesn't it? That takes energy, and energy you need to get back in order to break even (energy) or break even (money).
Right now, there are some severe issues with getting it to work at all.
But, let's assume that tomorrow there is a breakthrough and it all magically works perfectly.
The problem is that most of the energy of the fusion reaction comes out in the form of neutrinos, which you can't practically stop, some heat, but mostly fast neutrons.
The fast neutrons don't dump their energy into heat energy very easily at all. The best scheme I heard for doing that was lining the inside of the fusion reactor with lithium, transmute that for a bit and then stuff the lithium into a conventional fission reaction and use THAT to make steam.
And that's the most realistic scheme I am aware of. The fission reactors, and the disposal issues of all the elements that are getting irradiated make this very far from being a clean process. Fusion power is never going to be clean.
Re:AskMe Services Do Not Cost $, Right?
on
IANAL
·
· Score: 2
Yeah and everyone thought he was a LAWYER?
No. That's not the way it works!;-)
Re:Dumb Question from a NON Physicist
on
Universe is Flat
·
· Score: 2
>One thing that puzzled me with this analogy is
>that, for this to work, the galaxies had to be
>taped-on solid items. If galaxies are just
>collections of space (a bunch of dots) then why
>wouldn't the dots inside the galaxy fly apart, too
They are, but the force of gravity keeps them stuck together. In fact the planets are orbiting in stable orbits just slightly smaller (for their orbital velocity) than they would be if the universe wasn't expanding- the extra gravitation acceleration from being closer together cancels the expansion 'acceleration'.
So the upshot is that things that aren't in orbit drift apart. Things that are in orbit stay stuck that way at the same distance.
The reason is that the genes don't exactly have a marker at each end to delineate them. The genes are to some extent a matter of definition. They're different lengths, they can sometimes be found in different places, and sometimes 'two genes' do exactly the same thing even though they read quite differently.
Some bacteria have been found with two or three sets of genes sort of ontop of each other- starting with different offsets. Its a bit like code that you can jump to at 0x2000 or 0x2001 and it does different, but useful things!
Anyway reverse engineering this lot will take a while...
We're not going to run out of petroleum products any time soon. The price may go up; perhaps a lot, but that's about all; and fuel cost is less than 1% of launching a rocket anyway.
It is possible to make kerosine from biomass if we really wanted to.
The fraction of CO2 produced by rocketry is totally irrelevant next to the huge amounts used to drive cars or generate electricity. It's going to be maybe one hundred years before we reach the point where launch vehicles are significant; and the technology will probably shift to beamed solar energy or something by then anyway.
Finally, Hydrogen is more expensive because it takes more energy to produce. Practically speaking, unless you use nuclear power (or perhaps even;-), that means that Hydrogen is less environmentally friendly and uses more fossil fuels.
That's the case in Everquest as well, in most areas. And Everquest isn't even beta.
Everquest decided that they didn't want to bother with having to write fast code to run on the servers to path the monsters through the front door, so they didn't bother.
This means that monsters attack and kill from OUTSIDE, and YOU CAN'T FIGHT BACK. Many times I would get killed in a shop from a lion or other monster from outside, without any warning at all.
So I gave up playing Everquest. Sometimes I almost miss it; and then I remember 'details' like this...
Apparently it counted as a statement of opinion and didn't directly impune his professional standing; and it was clearly satirical, and hence protected by first amendment protection.
The space shuttle uses hydrogen. The problem with liquid hydrogen is that it has very low density. Six TIMES lower than other materials. This makes EVERYTHING bigger and hence heavier. Tanks, engines, pipes, pumps the lot. Extra weight in a rocket is not good.
Secondly, liquid hydrogen (LH) is a deep cryogenic fluid- the insulation values needed to keep it are very high, and this adds mass, plus it has lots of nasty habits like condensing oxygen from the air- LOX reacts with loads of things explosively.
If you do the simulations for an entire rocket, the performance of LH/LOX is entirely comparable to kerosine/LOX fuels- kerosine is much denser, lighter engines etc; but kerosine doesn't give as much kick per unit of fuel. So your rocket ends up heavier (more kgs of fuel), but the 'dry weight' is less. But this heavier rocket burns weight off much more quickly and hence goes as far as the LH/LOX.
Another advantage? Kerosine is a lot cheaper than hydrogen, even allowing for needing more of it. Kerosine can be carried in trucks.
Another? The kerosine/LOX rocket is much smaller (easier to build and transport).
I work in telecoms. In fact the systems I work on routinely switch hundreds of gigabits, all of which is inter-converted optical-electrical without any issues at all. There is no routing or switching bottleneck like that upto well past 10 gigabits/sec and DWDM allows you to scale past that (2-3 orders of magnitude past that).
The bust comes about because for every dollar invested, they were getting 50 cents back. Currently they can't borrow money. If you can't borrow money your business is in big trouble. They just can't afford to buy the boxes to stick on each end of the fiber right now.
That's what's happening. It's a financial, not a technical issue.
Nah. The backbone has plenty of scope to grow. Each fiber has a theoretical maximum throughput of about 100 terabits per second. They typically use 10 gigabits per second or less; i.e. 10,000 times less than the ultimate capacity.
And that's without laying more. When the fiber gets full, they can lay some more fibers next to the existing one. It's not like it takes up real estate like building roads does.
As long as the users demand more bandwidth and are prepared to pay for the bandwidth then the backbone is going to continue to grow. That's the bottom line.
Deliberate nuclear explosions are illegal in space. However most rocket engines are not supposed to explode, strangely enough.
However, there have been designs (e.g. Orion) which rely on throwing nuclear warheads out the back, and then catching the blast- they're not allowed under the law.
100 base T? Pah. Come back when these transceivers do 10G. Their equipment has atleast 800 times the capacity than yours, single mode, capable of DWDM and protected- yours is unprotected. It also has greater range; and only costs 100 times more.
First, the fiber, whilst not cheap, is peanuts compared to the cost of digging and laying; and if you think you're ever going to need more fiber, you'd want to stuff as much fiber as possible down the hole.
Secondly the equipment at each end is much cheaper the costs of laying new fiber; and they haven't had to install that yet.
Third, the high speed backbone isn't the biggest cost of getting wired; bigger costs are found in the last mile. That's why we get a flat charge for internet usage, independent of distance, in fact.
The dark fiber is actually an asset, and according to Gilder's law (bandwidth doubles every year), it's going to be used in the next 5 years. If those companies hadn't laid it, it would have cost many times more in the long run; and guess who would have had to stump up the money? Us. The bandwidth consumers.
The bandwidth equivalent of Moore's law (Gilder's Law), says that the rate of increase of data doubles about every year in the center of the network. So it doesn't take many years before even a 5% utilised system gets filled.
OK, for the skeptics out there, that's as fast or faster that Moore's Law, so how come we don't all have gigabit pipes going to our PCs by now?
Well, the growth curve started later, from a very much smaller number- we used to have 1200 baud, on a 1 MIP processor.
Anyway, each fiber can take perhaps 10 terabits right now; but the boxes to actually send that down a fiber are somewhat expensive (~250 lasers on different wavelengths); so nobody is using fully the bandwidth of even one fiber.
QWEST installed 48 fibers per conduit, last I heard they were using about 3. And they have a spare conduit.
Slashdot Mirror
Let's see:
a) don't have to pay per use of the roads (mostly)
b) don't have guaranteed quality of service (traffic jams)
c) can't make money from the roads (unless you are a roadbuilder)
d) some people make money shipping stuff around though
e) some people make money building stuff to use the roads
f) some people make very small amount of money telling you were to find things (map makers)
g) roads cost tax money to build and run, yet don't directly make ANY money!
Yeah, and the people who pay for the roads don't usually make money back from them! All these roads are therefore a commercial failure, and we need to privatise all of them so that businesses can make money. It's obvious! How could I have missed it?
That's what RSVP in IPv6 gives you. They 'reserve' some bandwidth for high priority traffic. If it doesn't get used then it gets filled with casual traffic, web browsing, ftp, mail etc. VOIP and Videophone/Quake IV stuff gets first dibs.
Uh? Quake IV? Is that important? Well, you will probably have a quota of high priority traffic, (say, only 1/10 of your bandwidth allowed to be high priority), and then you have to pay extra after that. So Quake IV doesn't use much bandwidth, so would fit inside your quota.
Impossible? I don't think so. All you have to do is each time somebody receives a junk email they mark it as junk email, the mail software can calculate one checksum starting at a random place in the file, and upload it to a checksum server. For any frequently received junk email the server will fairly quickly get enough checksums that the whole document will be covered.
When anybody receives an email, they can check a handful of random checksums against the checksum server, if enough of them match, then do a few more to be sure and deal with the email according to any settings by the user.
Still, there are issues. What happens if the email marketeers start appending random web pages to their email to dilute it down? What percentage of similarity is enough? There are some fixes- I think to be successful junk mail has to be fairly short- people rarely page down to cut to the chase; but adjusting the checksum points to emphasise the beginning and end of the email is probably a good thing.
>Aren't there algorithms that will report messages that are pretty close?
Yeah, there are. 'Rdist' does this as a way of trying to only send the minimum set of changes necessary to keep two ftp/web sites synchronised.
Actually to be precise, the checksum isn't imprecise, as rdist relies on checksums of subsets of the documents they are trying to synchronise.
This neatly sidesteps the counter issue...
The big issue is counters and other subtle changes to the emails that would destroy a naive checksum.
However multiple checksums of subsets of the email would not usually all be changed by one or a few changes/counters and checksums will be sufficiently discriminating to screen emails and can do a very good jobs of detecting any widespread junk emails.
It would be difficult that all checksums of all characters of a particular length (say 20 characters) be made sufficiently different that ALL of the subsets of the junk emails can be different.
(Checksums that checksum all the strings for a particular length are not difficult to generate as a matter of fact; little more than a circular buffer is required.)
Yes. The thrust per kg is 30-50% higher for hydrogen, but the density is 6x lower, so you have to shift many times more liters for the same thrust.
IRC Helium-3 isn't very common. Where you gonna get it from?
Secondly, how easily does D-3He fuse? It takes a MUCH higher temperature and pressure doesn't it? That takes energy, and energy you need to get back in order to break even (energy) or break even (money).
Right now, there are some severe issues with getting it to work at all.
But, let's assume that tomorrow there is a breakthrough and it all magically works perfectly.
The problem is that most of the energy of the fusion reaction comes out in the form of neutrinos, which you can't practically stop, some heat, but mostly fast neutrons.
The fast neutrons don't dump their energy into heat energy very easily at all. The best scheme I heard for doing that was lining the inside of the fusion reactor with lithium, transmute that for a bit and then stuff the lithium into a conventional fission reaction and use THAT to make steam.
And that's the most realistic scheme I am aware of. The fission reactors, and the disposal issues of all the elements that are getting irradiated make this very far from being a clean process. Fusion power is never going to be clean.
Yeah and everyone thought he was a LAWYER?
;-)
No. That's not the way it works!
>One thing that puzzled me with this analogy is
>that, for this to work, the galaxies had to be
>taped-on solid items. If galaxies are just
>collections of space (a bunch of dots) then why
>wouldn't the dots inside the galaxy fly apart, too
They are, but the force of gravity keeps them stuck together. In fact the planets are orbiting in stable orbits just slightly smaller (for their orbital velocity) than they would be if the universe wasn't expanding- the extra gravitation acceleration from being closer together cancels the expansion 'acceleration'.
So the upshot is that things that aren't in orbit drift apart. Things that are in orbit stay stuck that way at the same distance.
The reason is that the genes don't exactly have a marker at each end to delineate them. The genes are to some extent a matter of definition. They're different lengths, they can sometimes be found in different places, and sometimes 'two genes' do exactly the same thing even though they read quite differently.
Some bacteria have been found with two or three sets of genes sort of ontop of each other- starting with different offsets. Its a bit like code that you can jump to at 0x2000 or 0x2001 and it does different, but useful things!
Anyway reverse engineering this lot will take a while...
We're not going to run out of petroleum products any time soon. The price may go up; perhaps a lot, but that's about all; and fuel cost is less than 1% of launching a rocket anyway.
;-), that means that Hydrogen is less environmentally friendly and uses more fossil fuels.
It is possible to make kerosine from biomass if we really wanted to.
The fraction of CO2 produced by rocketry is totally irrelevant next to the huge amounts used to drive cars or generate electricity. It's going to be maybe one hundred years before we reach the point where launch vehicles are significant; and the technology will probably shift to beamed solar energy or something by then anyway.
Finally, Hydrogen is more expensive because it takes more energy to produce. Practically speaking, unless you use nuclear power (or perhaps even
>Monsters can attack through walls.
That's the case in Everquest as well, in most areas. And Everquest isn't even beta.
Everquest decided that they didn't want to bother with having to write fast code to run on the servers to path the monsters through the front door, so they didn't bother.
This means that monsters attack and kill from OUTSIDE, and YOU CAN'T FIGHT BACK. Many times I would get killed in a shop from a lion or other monster from outside, without any warning at all.
So I gave up playing Everquest. Sometimes I almost miss it; and then I remember 'details' like this...
Apparently it counted as a statement of opinion and didn't directly impune his professional standing; and it was clearly satirical, and hence protected by first amendment protection.
(Also covered here).
The space shuttle uses hydrogen. The problem with liquid hydrogen is that it has very low density. Six TIMES lower than other materials. This makes EVERYTHING bigger and hence heavier. Tanks, engines, pipes, pumps the lot. Extra weight in a rocket is not good.
Secondly, liquid hydrogen (LH) is a deep cryogenic fluid- the insulation values needed to keep it are very high, and this adds mass, plus it has lots of nasty habits like condensing oxygen from the air- LOX reacts with loads of things explosively.
If you do the simulations for an entire rocket, the performance of LH/LOX is entirely comparable to kerosine/LOX fuels- kerosine is much denser, lighter engines etc; but kerosine doesn't give as much kick per unit of fuel. So your rocket ends up heavier (more kgs of fuel), but the 'dry weight' is less. But this heavier rocket burns weight off much more quickly and hence goes as far as the LH/LOX.
Another advantage? Kerosine is a lot cheaper than hydrogen, even allowing for needing more of it. Kerosine can be carried in trucks.
Another? The kerosine/LOX rocket is much smaller (easier to build and transport).
I work in telecoms. In fact the systems I work on routinely switch hundreds of gigabits, all of which is inter-converted optical-electrical without any issues at all. There is no routing or switching bottleneck like that upto well past 10 gigabits/sec and DWDM allows you to scale past that (2-3 orders of magnitude past that).
The bust comes about because for every dollar invested, they were getting 50 cents back. Currently they can't borrow money. If you can't borrow money your business is in big trouble. They just can't afford to buy the boxes to stick on each end of the fiber right now.
That's what's happening. It's a financial, not a technical issue.
Nah. The backbone has plenty of scope to grow. Each fiber has a theoretical maximum throughput of about 100 terabits per second. They typically use 10 gigabits per second or less; i.e. 10,000 times less than the ultimate capacity.
And that's without laying more. When the fiber gets full, they can lay some more fibers next to the existing one. It's not like it takes up real estate like building roads does.
As long as the users demand more bandwidth and are prepared to pay for the bandwidth then the backbone is going to continue to grow. That's the bottom line.
Deliberate nuclear explosions are illegal in space. However most rocket engines are not supposed to explode, strangely enough.
However, there have been designs (e.g. Orion) which rely on throwing nuclear warheads out the back, and then catching the blast- they're not allowed under the law.
>First...how in the hell do you 'pirate' something that is free?
It's free as in not locked up, not free as in free beer.
To pirate GPLd software, you fork the code, make it closed source, then sell it with extra features for money.
It's happened before to Richard Stallman. First he heard of it was when people contacted him to support the new features. That went down well. Not.
And that's why the GPL exists.
Unfortunately, the GPL is based on copyright law in the West. But the chinese don't have a copyright law, so it doesn't look like it applies there.
OTOH IANAL
Oops. That's unfair. It's more like 50 times the cost.
What a waste of a fiber!
100 base T? Pah. Come back when these transceivers do 10G. Their equipment has atleast 800 times the capacity than yours, single mode, capable of DWDM and protected- yours is unprotected. It also has greater range; and only costs 100 times more.
Of course prices aren't dropping!
First, the fiber, whilst not cheap, is peanuts compared to the cost of digging and laying; and if you think you're ever going to need more fiber, you'd want to stuff as much fiber as possible down the hole.
Secondly the equipment at each end is much cheaper the costs of laying new fiber; and they haven't had to install that yet.
Third, the high speed backbone isn't the biggest cost of getting wired; bigger costs are found in the last mile. That's why we get a flat charge for internet usage, independent of distance, in fact.
The dark fiber is actually an asset, and according to Gilder's law (bandwidth doubles every year), it's going to be used in the next 5 years. If those companies hadn't laid it, it would have cost many times more in the long run; and guess who would have had to stump up the money? Us. The bandwidth consumers.
The bandwidth equivalent of Moore's law (Gilder's Law), says that the rate of increase of data doubles about every year in the center of the network. So it doesn't take many years before even a 5% utilised system gets filled.
r e.pdf
OK, for the skeptics out there, that's as fast or faster that Moore's Law, so how come we don't all have gigabit pipes going to our PCs by now?
Well, the growth curve started later, from a very much smaller number- we used to have 1200 baud, on a 1 MIP processor.
Anyway, each fiber can take perhaps 10 terabits right now; but the boxes to actually send that down a fiber are somewhat expensive (~250 lasers on different wavelengths); so nobody is using fully the bandwidth of even one fiber.
QWEST installed 48 fibers per conduit, last I heard they were using about 3. And they have a spare conduit.
Anyway, check out: http://www.research.att.com/~amo/doc/internet.moo
for more info on the large packet growth that is being seen.
Or even worse, have they told Cyc that humans don't need batteries? I really don't like the idea of Cyc getting that one wrong 8-)
So it's already passed the Turing test? Wow ;-)