This post is incomplete because of problems with html markings. Please see the complete post below (and mod this one down!)
(sorry for the duplicated posting; the previous one was cut because of problems with the html marks)
In order to obtain a 90% reduction in the energy bill, cooling must account for 90% of the power of the DC. This implies a PUE >= 10. As a reference, 5 years ago virtually any DC had a PUE lower than 3. Nowadays, PUE lower than 1.15 can be obtained easily. As a referecence, Facebook publishes the instantaneous PUE of one of its DC in Prineville, which at the moment is 1.05. This implies that any savings in cooling would reduce the bill, at much, in a factor of 1.05 (1/1.05 = 0.9523).
On the other hand, I believe that this is not the first commertial offer for a liquid-cooled server, Intel was already considering two years ago, and the idea has been discussed in other forums for several years. I can't remember right now which company that was actually selling these solutions, but I believe it was already in the market.
In order to obtain a 90% reduction in the energy bill, cooling must account for 90% of the power of the DC. This implies a PUE >= 10. As a reference, 5 years ago virtually any DC had a PUE instantaneous PUE of one of its DC in Prineville, which at the moment is 1.05. This implies that any savings in cooling would reduce the bill, at much, in a factor of 1.05 (1/1.05 = 0.9523).
On the other hand, I believe that this is not the first commertial offer for a liquid-cooled server, Intel was already considering it two years ago, and the idea has been discussed in other forums for several years. I can't remember right now which company that was actually selling these solutions, but I believe it was already in the market.
Homework is part of the learning process; helping with homework prevents the kid from doing them and, in the process, learning. Solving math problems for homework, as an example, is not because the teacher wants to know the final answer; it's because the teacher wants the student to confront a new type problem and, in the process of confronting it and guessing how to obtain the solution, learn. I give detailed solutions to the class problems to my undergraduate students (they would obtain them anyway, and in many cases with errors), but I always insist that looking at the solution should be the last resort if they don't know how to face the problem (solutions are intended for checking their own's).
The problem with external help (from the parents, typically) is that, in many cases, the parents get involved in excess and actually do the homework for their sons, so the teacher cannot find any error in the child's results. I know a case of a mother who was doing exactly this, because his kid didn't get very good grades (I was even asked for help in some work the child had to do for school with the computer!). The grades started getting worse and, three years later, the kid was in special education. I know this is not the only reason, but I'm confident it affects a lot.
The first step is to classify the data in two groups: what you would not want to lose at any cost, and the redundant data (movies, music, etc) that you could survive without. This is the most important step
The second step is to backup the important data using an external 1 TB drive, tape or similar.
Optionally, the third step is to delete the remaining 19 TB.
This problem occurs even for people in the same group, who often find problems to repeat the simulations from our own papers, and even as recent as one year ago. The problems typically come from people leaving (PhD finished, grants that expire, people that move to a different job), changes in the simulation tools, etc.
In our Computer Architecture research group we employ Mercurial for versioning the simulator code. Thus, we can know when each change was applied. For each simulation, we store both the configuration file that is used to generate that simulation (which also includes the Mercurial version of the code which is being used) and the simulation results, or at least only the interesting results. Multiple simulators allow for different verbosity levels, and in most cases most of the output is useless, so we typically store the interesting data (such as latency and throughput) because otherwise we would have no disk space.
Even with this setup, we often find problems trying to replicate the exact results of our own previous papers, for example because of poor documentation (this is typical in research, since homebrew simulation tools are not maintained as one would expect from commertial code), changes that introduce subtle effects, code that gets lost when some person leaves or simply large files that get deleted to save disk space (for example, simulation checkpoints or network traces, which are typically very large).
However, you typically do not need to look back and replicate results, so keeping all the data is a useless effort. I completely understand that research data gets lost, but I think that it is largely unavoidable.
Sure it dissapears!
Unless you're running IE as admin, you have UAC disabled and the malware has installed a hypervisor and you're hickjacked forever without having any chance to detect it. How long before we see that?
Yet still it does not support turning off the computer, despite being a feature requested for years. That's the ONLY missing feature which prevents it from being my default video player
CODEC: COder-DECoder; but there is no (en)COder here!
all ISPs are deliberately vague about what qualifies as a 'server.'
The fact that some programs might behave correctly when implementing a server, or not (eg: skype) or the fact that, in some cases, ISPs allow certain services or ports, does not mean that a 'server' is something arcane. It's you that don't know it.
The link to the actual Nature Communications paper is here: Non-volatile memory based on the ferroelectric photovoltaic effect.
This somehow resembles Phase-Change Memory (PCM). PCM devices are composed of a material which, under a high current, there is a thermal fusion and changes to a different material status, from amorphous to crystalline. This changes two properties: light reflectivity (exploited in CDs and DVDs) and electrical resistance (exploited in emerging non-volatile PCM memories). The paper cites PCM and other types of emerging non-volating memories.
In this case, it is the polarization what changes, without requiring a thermal fusion, therefore increasing the endurance of the device, one of the main shortcomings of PCM. The other main shortcoming of PCM is write speed due to the slow thermal process, in the paper they claim something like 10ns. If this can be manufactured with a large scale of integration and low cost, it will probably be a revolution in computer architecture.
GB != Gbps.
"the existence of any finite bound, no matter how large, means that that the gaps between consecutive numbers don't keep growing forever"
Actually, I disagree with the unfortunate writing of the sentence. The gaps between consecutive prime numbers are variable, and on average they DO tend to keep growing forever. This is a widely known result, the density of prime numbers decreases as the numbers grow. However, since the gap between consecutive primes is variable and it does not follow a regular function (otherwise, it would be very easy to calculate prime numbers), even with a very low density of prime numbers we can find a pair of consecutive prime numbers with a gap of only 2.
The problem under study is not wether the gap between consecutive primes keeps growing forever (which is true only on average, considering a long secuence of integers), but wether there are infinite such pairs of primes with gap 2. The new result found says that there exist infinite pairs of primes with gap 70M or less. However, this does not imply at all that no consecutive pairs of primes with gap > 70M exist (which, in fact, they do).