Large bright stars don't last nearly as long as smaller dimmer ones like the Sun, and it's the big ones that actually explode at the end of their lives and spray heavy elements into the interstellar medium, so, especially in the early life of a galaxy, gas may get processed through many generations of big stars.
Just did a bit of checking. For £249 including VAT you can get a mini-tower, dual core midrange CPU and 2GB RAM. A dozen or so of these and a switch looks very appealing if there is space. 300W PSU, so cluster should be under 5kW.
If your friend doesn't want to do a lot of engineering work, then for this price I would just buy 10 or so PCs (depending on memory/CPU tradefoffs) from wherever has a special offer, plus a gigabit switch and put them on shelves. If you need a lot of memory, or can usefully share memory then that would be a bit different, but you can buy a usable headless PC for £300-£400. This will also not be terribly power efficient, nor will components like motherboards be of the highest quality, but you get more bang for the buck that way than almost anything else except second-hand. At the other extreme, you could probably buy a single 24-core AMD box for the money with quite a lot of RAM and just run a lot of processes on it.
Talking of second-hand, the other thing to do is to see if anyone has a cluster they can't feed (ie power) any more. Our aplied maths dept is about to shut down a 3 year old 1000-core cluster because they can't afford the power to run it and their newer 2000 core cluster. A slice of that would be great and someone locally might be able to help you in a similar way.
Can I ask the same question for particle physics -- specifically non-abelian gauge theories. I'd like to be able to under stand the Higgs mechanism and supersymmetry properly and how the particles emerge from the symmetries of the fields.
My pure maths background is quite strong, but I stopped doing applied somewhere in my second undergraduate year and have forgotten most of the more advanced bits of it. So I have a hazy memory of curvilinear coordinates, and an even hazier one of Hamiltonians and Lagrangians. I can still more or less remember my SR course. On the positive side, I understand Lie groups and Lie algebras and their representation theory pretty well.
There are magnetohydrodynamic approaches. You make a lot of hot plasma, cool it by allowing to expand in one direction and then use a big magnet to separate the positive ions and negative electons, which impact different electrodes. I don't think it's terribly efficient (to put it mildly) and the wear on the electrodes is something chronic, but if you want a LOT of power (GW) for short periods (seconds to minutes) for some reason it might be usable. I think Jerry Pournells has a laser launcher powered that way, using rocket engines as the plasma source.
The idea, I think is that these servers are your cloud infrastructure, rather than being used for any local purpose. Imagine a future where computer technology is a bit more stable than it is now, so a server has a 10 year or so useful life before becoming obsolete. Also you have fibre to every apartment building or office block.
Now, you want to convert some electricity into heat for whatever reason. So you buy/rent a "brick" of servers of suitable size, probably an all-solid state affair with no moving parts at all, plug it into the power and the internet and arrange to move heat out of it for whatever purpose you have. As far as you're concerned that's it, and this is cheaper for you than just buying or renting a conventional electric heating element (ie you get paid, or subsidised power for doing it).
As far as the user of the computation is concerned, they buy computation and related services from Amazon or someone, just as they do now.
The middle-man is running a complex management layer that migrates VM instances and data around the millions of "bricks" that they manage, and allocates each as much work to do as the demand for its heat output requires. Balancing the compute demand against the heat demand requires partly scale, partly non-urgent background jobs, partly blanacing load between time zones and hemispheres and partly a few conventional data centres that can fill in any gap.
Do the sums. 1 ZB = 10^9 TB. a TB had drive costs c US$50, probably less in quantity, so information storage is US$50 billion/year industry. Doesn't seem implausible to be honest.
Bst learning advice for CS I ever heard was to write an Operating System. Admittedly this was advice to 1st year University students for what to do after the summer, but it should still be sound for high school. All the information needed is out there.
Twitter is not, in any reasonable sense, a place to have private conversations. A more interesting question perhaps is whether this is slander (defamation in a public but transitory form, as by telling a lot of people verbally) and defamation in a permanent form (as by printing a book). In fact, in this day and age is slander even possible?
The SI units have been defined in non-Earth centric ways for many many years now. A minute is 60 seconds where a second is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. Which is the same throughout the entire the universe and to the best of our knowledge the same for all time.
This measurement suffers from the same problem. Define a second at a point in time when a caesium-133 atom had never existed. We base our units of time on things that exist today and still don't even really have a solid grasp of what we are even measuring. At least, I have never heard of anyone claim to have a complete understanding of time, what it is, whether it exists naturally or is purely a construct of (human) consciousness and exactly how we all travel through it..
I don't know about complete, but Stephen Hawkings "A Brief History of Time" (and the real physics textbooks underlying the popularisation) show a pretty good degree of understanding.
As for measuring time. We rely on our (extensive) observation that lots of other processes in the universe correlate very well with the oscillation of the radiation...caesium-133 atom. So if the half life of a neutron is roughly 9 trillion cycles of that radiation one day, it seems to be the same the next day and in the next lab and (via slightly more indirect measurements) on distant stars and so on. That fact that all these experiments correlate is what leads us to believe that time is a measurable well-behaved quantity that might be intersting. So we can use (for example) neutron decay as a "secondary time standard".
You start by finding a complex hamiltonian with a ground state describing the solution to your problem
I'm not a math whiz, but to me, this says: "You already know the answer to the problem"...
No. You can think of this as posing the question in a very specific way -- a little constructing a wire frame so that soap films on it naturally form the shape of the best surface for some purpose.
The open question is what questions can in fact be posed this way?
A traditional digital computer is pretty hellish to program too if you take away all the props -- you have to find a set of bit values for the memory such this immense consrtructrion of hundreds of millions of gates, clocks, latches, etc. will evolve to give your answer in a reasonably ti,me.
An Adiabatic Quantum Computer is quite a different beast from a quantum computer in the usual sense, and even if it can solve the same class of problems in polynomial time (not at all obvious at this stage) it isn't at all clear that 1 qubit in this machine does the same work as 1 traditional qubit.
They are, to be honest, being a little bit naughty calling this a quantum computer at all, although it does compute and has quanta, but so does my phone.
I'm not saying the TSA are right. I also find them annoying, and probably ineffective. I was just taking issue with your specific claim: "The TSA has done nothing to make us more secure." which seems overbroad.
Of course most private enterprise attempts fail. Seen as a whole, the private sector does more or less what the government does -- try out lots of approaches and fund each until it's die-hard advocates finally can't scare up any more money from anywhere. It's advantage, if it has one is that it is a bit harder to fiddle the financers into flogging a dead horse.
The article is very misleadingly written, and the whole "gas stations" idea is misleading.
Think of something more like mid-air refueling.
The sort of mission they are considering might include launching two or three big boosters, one with the real payload and the rest with fuel. Then transfer the spare fuel to the uppser stage of the booster with the real payload and it has enough fuel for the transfer to a Lunar or Mars transfer orbit (and maybe for orbital insertion at the other end and even the return transfer.
Once you can do that, and assuming you can keep the fuel stable for long enough, you can play the same game again in lunar or Mars orbit.
Cute, but still impractical. "What department" Mr X is just a former lawyer who now works for us as a copyright administrator. He's in the Country & Western department"
I've thought about this idea before. It's a nice idea, but big corporations would just employ in-house advisers and lawyers and claim that they were spending nothing on advice for the case, just doing the equivalent of representing themselves.
Slashdot Mirror
Large bright stars don't last nearly as long as smaller dimmer ones like the Sun, and it's the big ones that actually explode at the end of their lives and spray heavy elements into the interstellar medium, so, especially in the early life of a galaxy, gas may get processed through many generations of big stars.
That's actually impossible. The meter (or possibly the second) is defined by fixing the value of c.
Just did a bit of checking. For £249 including VAT you can get a mini-tower, dual core midrange CPU and 2GB RAM. A dozen or so of these and a switch looks very appealing if there is space. 300W PSU, so cluster should be under 5kW.
If your friend doesn't want to do a lot of engineering work, then for this price I would just buy 10 or so PCs (depending on memory/CPU tradefoffs) from wherever has a special offer, plus a gigabit switch and put them on shelves. If you need a lot of memory, or can usefully share memory then that would be a bit different, but you can buy a usable headless PC for £300-£400. This will also not be terribly power efficient, nor will components like motherboards be of the highest quality, but you get more bang for the buck that way than almost anything else except second-hand. At the other extreme, you could probably buy a single 24-core AMD box for the money with quite a lot of RAM and just run a lot of processes on it.
Talking of second-hand, the other thing to do is to see if anyone has a cluster they can't feed (ie power) any more. Our aplied maths dept is about to shut down a 3 year old 1000-core cluster because they can't afford the power to run it and their newer 2000 core cluster. A slice of that would be great and someone locally might be able to help you in a similar way.
In fact you correct the error by observing it.
Can I ask the same question for particle physics -- specifically non-abelian gauge theories. I'd like to be able to under stand the Higgs mechanism and supersymmetry properly and how the particles emerge from the symmetries of the fields.
My pure maths background is quite strong, but I stopped doing applied somewhere in my second undergraduate year and have forgotten most of the more advanced bits of it. So I have a hazy memory of curvilinear coordinates, and an even hazier one of Hamiltonians and Lagrangians. I can still more or less remember my SR course. On the positive side, I understand Lie groups and Lie algebras and their representation theory pretty well.
There are magnetohydrodynamic approaches. You make a lot of hot plasma, cool it by allowing to expand in one direction and then use a big magnet to separate the positive ions and negative electons, which impact different electrodes. I don't think it's terribly efficient (to put it mildly) and the wear on the electrodes is something chronic, but if you want a LOT of power (GW) for short periods (seconds to minutes) for some reason it might be usable. I think Jerry Pournells has a laser launcher powered that way, using rocket engines as the plasma source.
The idea, I think is that these servers are your cloud infrastructure, rather than being used for any local purpose.
Imagine a future where computer technology is a bit more stable than it is now, so a server has a 10 year or so useful life before becoming obsolete. Also you have fibre to every apartment building or office block.
Now, you want to convert some electricity into heat for whatever reason. So you buy/rent a "brick" of servers of suitable size, probably an all-solid state affair with no moving parts at all, plug it into the power and the internet and arrange to move heat out of it for whatever purpose you have. As far as you're concerned that's it, and this is cheaper for you than just buying or renting a conventional electric heating element (ie you get paid, or subsidised power for doing it).
As far as the user of the computation is concerned, they buy computation and related services from Amazon or someone, just as they do now.
The middle-man is running a complex management layer that migrates VM instances and data around the millions of "bricks" that they manage, and allocates each as much work to do as the demand for its heat output requires. Balancing the compute demand against the heat demand requires partly scale, partly non-urgent background jobs, partly blanacing load between time zones and hemispheres and partly a few conventional data centres that can fill in any gap.
Do the sums. 1 ZB = 10^9 TB. a TB had drive costs c US$50, probably less in quantity, so information storage is US$50 billion/year industry.
Doesn't seem implausible to be honest.
The article says they can communicate with one another.
Bst learning advice for CS I ever heard was to write an Operating System. Admittedly this was advice to 1st year University students for what to do after the summer, but it should still be sound for high school. All the information needed is out there.
Actually I think they are less common. Don't fission reactors emit electron anti-neutrinos?
Assuming none of them record it on their phones
Twitter is not, in any reasonable sense, a place to have private conversations. A more interesting question perhaps is whether this is slander (defamation in a public but transitory form, as by telling a lot of people verbally) and defamation in a permanent form (as by printing a book). In fact, in this day and age is slander even possible?
One more point, I left out.
The SI units have been defined in non-Earth centric ways for many many years now. A minute is 60 seconds where a second is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. Which is the same throughout the entire the universe and to the best of our knowledge the same for all time.
This measurement suffers from the same problem. Define a second at a point in time when a caesium-133 atom had never existed. We base our units of time on things that exist today and still don't even really have a solid grasp of what we are even measuring. At least, I have never heard of anyone claim to have a complete understanding of time, what it is, whether it exists naturally or is purely a construct of (human) consciousness and exactly how we all travel through it. .
I don't know about complete, but Stephen Hawkings "A Brief History of Time" (and the real physics textbooks underlying the popularisation) show a pretty good degree of understanding.
As for measuring time. We rely on our (extensive) observation that lots of other processes in the universe correlate very well with the oscillation of the radiation ...caesium-133 atom. So if the half life of a neutron is roughly 9 trillion cycles of that radiation one day, it seems to be the same the next day and in the next lab and (via slightly more indirect measurements) on distant stars and so on. That fact that all these experiments correlate is what leads us to believe that time is a measurable well-behaved quantity that might be intersting. So we can use (for example) neutron decay as a "secondary time standard".
You start by finding a complex hamiltonian with a ground state describing the solution to your problem
I'm not a math whiz, but to me, this says: "You already know the answer to the problem"...
No. You can think of this as posing the question in a very specific way -- a little constructing a wire frame so that soap films on it
naturally form the shape of the best surface for some purpose.
The open question is what questions can in fact be posed this way?
A traditional digital computer is pretty hellish to program too if you take away all the props -- you have to find a set of bit values for the memory such this immense consrtructrion of hundreds of millions of gates, clocks, latches, etc. will evolve to give your answer in a reasonably ti,me.
An Adiabatic Quantum Computer is quite a different beast from a quantum computer in the usual sense, and even if it can solve the same class of problems in polynomial time (not at all obvious at this stage) it isn't at all clear that 1 qubit in this machine does the same work as 1 traditional qubit.
They are, to be honest, being a little bit naughty calling this a quantum computer at all, although it does compute and has quanta, but so does my phone.
I'm not saying the TSA are right. I also find them annoying, and probably ineffective. I was just taking issue with your specific claim: "The TSA has done nothing to make us more secure." which seems overbroad.
How do you know how many plots have been abandoned because the plotters couldn't work out a reliable way past TSA screening?
I don't know either, and it might be none, but you appear to know that it is none.
Of course most private enterprise attempts fail. Seen as a whole, the private sector does more or less what the government does -- try out lots of approaches and fund each until it's die-hard advocates finally can't scare up any more money from anywhere. It's advantage, if it has one is that it is a bit harder to fiddle the financers into flogging a dead horse.
The article is very misleadingly written, and the whole "gas stations" idea is misleading.
Think of something more like mid-air refueling.
The sort of mission they are considering might include launching two or three big boosters, one with the real payload and the rest with fuel.
Then transfer the spare fuel to the uppser stage of the booster with the real payload and it has enough fuel for the transfer to a Lunar or Mars transfer orbit (and maybe for orbital insertion at the other end and even the return transfer.
Once you can do that, and assuming you can keep the fuel stable for long enough, you can play the same game again in lunar or Mars orbit.
But then do you have to pay them half the cost of your time to defend yourself?
Cute, but still impractical. "What department" Mr X is just a former lawyer who now works for us as a copyright administrator. He's in the Country & Western department"
I've thought about this idea before. It's a nice idea, but big corporations would just employ in-house advisers and lawyers and claim that they were spending nothing on advice for the case, just doing the equivalent of representing themselves.