In comparison, Singularity _does_ run, but it's missing many elements from a real OS. It's like a running concept care without air conditioning, radio, airbags or emission catallytic filters. OK, maybe with missing doors and windows as well.
I guess nothing stops one to port Firefox or the entire GNU suite to Singularity...
Sodium is not white - it is a silverly soft metal - similar in consistency with frozen butter. It can melt easily, and generates sodium vapors when heated. I didn't see sodium in the picture as it probably was alreayd covered with oxyde.
In fact when heated in air in quantities more than a few grams, sodium will simply burn (with violent flames) generating that white-yellow "smoke" which is a combination of sodium oxyde (Na2O) and sodium peroxyde (Na2O2).
Note that both sodium oxyde and sodium peroxyde are highly reactive, burning in contact with water, generating sodium hydroxide. Sodium peroxide also reacts violently with flammable organic materials that can easily "give" a hydrogen or hydroxil radical, such as alcohols. In this reaction, it generates more sodium hydroxide. Sodium vaports will slowly react with the oxygen in the air, again generating white sodium oxyde.
All these compounds will cause severe burns even if you expose the human skin to less than of gram of this stuff. Concentrated sodium hydroxyde simply melts the skin, nails and bones, and sodium oxyde/peroxyde is even more dangerous. In fact - this is how soap was made for centuries - just boil some fat in concentrated sodium hydroxyde and soon you will have some soap.
It's obvious why these workers have to wear special suits.
More fun stuff about sodium - check out the famous Sodium Party that Theodore Gray had a while back (or wikipedia)
None of the previous replies mention an important requirement - stopping the chain reaction is just half of the problem. The bigger problem is that the core is still generating lots of thermal energy days after you shutdown the reactor. You still need to actively cool the core for at least 1-2 weeks otherwise the core would eventually melt.
Why? Remember that in a nuclear reactor, heat comes from two different sources: 1) The primary heat source is the direct fission process (which generates around 170 MeV per fission in a U-235 reactor). This reaction is immediately stopped when you don't have a chain reaction anymore. 2) The secondary source is the decay process of fission products (around 15-20 MeV per fission if I remember correctly). These fission products are extremely radioactive (with half-life fron nanoseconds to days), and typically will decay into other products which can decay into others, etc. until you reach some compounds which have much longer half-lifes (weeks, months, years or more)
So, to conclude, even after you shutdown a reactor, you still have to dissipate significant heat (about 10-15% from the total heat generated) which can STILL melt the core. That's why you need sophisticated cooling systems that need to work in the eventuality of an accident.
This specific story made me realize something on digg vs. shashdot comparisons. Usually digg.com is a good source for early news, something that Slashdot ceased to be some time ago. I go more frequently to digg.com these days to get the latest cool news.
As an example, I saw this story a few days ago on digg.com (eight days ago, to be more exact).
But here is the interesting fact: the story barely got any diggs, even though I found it out as a very interesting story. But here on Slashdot, the story makes the first page, thankfully... So interesting stories have better changes to show up on Slashdot after all!
I don't know, franly, but I am not sure about using tubes because as someone else pointed out, beta radiation (and gamma rays too) would ionize the rarefied gas inside the tube, therefore affecting the flow of electrons (in fact this is one of the principles behind various designs of radiation detectors). But probably it might work in some conditions.
Another solution would be to use hardened semiconductors, with much bigger gates, etc. For example, in space you have cosmic rays (which, BTW are much more energetic than nuclear-generated gamma rays). NASA is using hardened electronic components which are able to withstand the random ionization generated by cosmic rays.
Ionizing radiations (usually beta/gamma radiation) can affect materials in various ways. For example, an energetic gamma-ray photon (around 0.3 MeV for the Cobalt-60 spectrum) would cause partial ionization of Si atoms in traditional semiconductors. Since the n/p difference is extremely small in a single transistor, you just need a few thousand ionizations in it to make it unusable.
>>> We calculated that, if acetylene is reacting with the hydrogen gas to turn it back into methane, quite a bit of energy is being released. So that's our basis for saying there is something to eat on Titan. We don't know if there are any customers, but there's something on the menu.
This reaction doesn't make any sense. The C-C bond is much too stronger to be broken by a small release of energy done by the hydrogen absorbtion. At worst, this will generate etylene in the first step, and then ethane in the second step.
>>> The study estimated that individual doses would end up being very high, at 2.26 sieverts.
Interesting. However, that this is 2.26 sieverts for the total mission. Usually, you get nausea, etc as part of the acute radiation syndrome, assuming that you are getting those in a few hours.
Error-correction in quantum algorithms is actually the key issue in future development of quantum computing. And, not only that, but you have to come up with a correction algorithm where the complexity scales polynomially with the size of the system. Also,
It is a hard problem - even if we have years of theoretical research, the first succesful experiment that probed the real error correction was done only few months ago (see Nature - Dec 1 2004), or http://www.eurekalert.org/pub_releases/2004-12/nio s-ndd112904.php
>>> And for those with tinfoil hats- keep in mind that some assume that we don't get real info from NASA- such as those who say that gravity on the moon is much closer to the Earth's gravity, unlike what we are told, but this can't be released because it would throw a Geurilla Wrench into the theory of relativity....
Believe me - any aspiring scientist would LOVE to throw a Guerilla Wrench into the theory of relativity. How does a Nobel prize sounds to you?
Re:Memory is _STILL_ a scarce resource!
on
Zeta Goes Gold
·
· Score: 1
I probably overreacted (given that you can buy today a 1 GB of DDR memory for less than $100). I agree - after all, if you have heavily executed code in the kernel module, then you better make sure that it stays in L1/(and especially L2) caches as much as possible.
Something seems to be wrong...
on
Zeta Goes Gold
·
· Score: -1, Troll
>>> ZETA is a very fast operating system written from the ground up to get more out of your hardware than any other. With a true micro kernel is of only 640 KB and a 64-bit journalling filesystem to make things fly.
>>> The Korean site, unlike U.S. versions, was operated by another company, which Microsoft did not identify. Microsoft's own experts and Korean police were investigating, but Microsoft believes the computers were vulnerable because operators failed to apply necessary software patches, said Sohn, an MSN director.
Don't trust other companies to apply security patches for your site.
This is one of the worst behchmark articles I read in a long time.
What is missing is a systematic analysis of DISK performance in respect to various dimensions: 1) Pure disk read vs. pure disk write vs mixed I/O/ 2) Sequential I/O vs random I/O vs. mixed 3) block size (512 bytes, 1K,... 256K), or various requests combined. 4) Does it matter when you have multiple RAID volumes vs. only one? (this matters especially for SW RAID) 5) Disk/LUN size.
Also, the performance numbers should include: 1) The average and max read/write time. Distribution patterns. 2) The average and max queue length in various workloads. 3) The predictability of these numbers. (which matters for SW RAID) 4) RAID recovery time 5) Performace numbers when the RAID set is broken (one disk is bad). 6) Performace numbers during RAID recovery (set rebuilding - i.e. after you replaced the bad disk with a good one).
It is also interesting to find out various I/O patterns for real-world deployments, for example a database, a file system, etc. Isolating the I/O pattern for common file system operations, or database deployemnts, and map them to the figures above.
And, one more thing - an administrator will likely deploy RAID for its main advantage - relatively good read performance combined with its low downtime when one disk goes bad. But there is a drawback - if one of the three disks goes bad, the performance will be severy affected. On a badly designed system, the performance drop might render the server unusable if it cannot stand up the continuous flow of requests. So it is very important to know the particular behavior during RAID recovery. This data is also missing from the article.
>>> I think PS/3 has the advantage and will eventually win. I'm surprised at the specs as original discussions on the machine had indicated it would be fitted with FOUR Cell processors, not one.
It's all about the relation with game publishers, the differences in terms of performance are insignifiant.
Remember that XBox was touted as much more powerful than PS2, however it didn't got enough market share...
Slashdot Mirror
http://vimeo.com/46304267
In comparison, Singularity _does_ run, but it's missing many elements from a real OS. It's like a running concept care without air conditioning, radio, airbags or emission catallytic filters. OK, maybe with missing doors and windows as well.
...
I guess nothing stops one to port Firefox or the entire GNU suite to Singularity
Sodium is not white - it is a silverly soft metal - similar in consistency with frozen butter. It can melt easily, and generates sodium vapors when heated. I didn't see sodium in the picture as it probably was alreayd covered with oxyde.
In fact when heated in air in quantities more than a few grams, sodium will simply burn (with violent flames) generating that white-yellow "smoke" which is a combination of sodium oxyde (Na2O) and sodium peroxyde (Na2O2).
Note that both sodium oxyde and sodium peroxyde are highly reactive, burning in contact with water, generating sodium hydroxide. Sodium peroxide also reacts violently with flammable organic materials that can easily "give" a hydrogen or hydroxil radical, such as alcohols. In this reaction, it generates more sodium hydroxide. Sodium vaports will slowly react with the oxygen in the air, again generating white sodium oxyde.
All these compounds will cause severe burns even if you expose the human skin to less than of gram of this stuff. Concentrated sodium hydroxyde simply melts the skin, nails and bones, and sodium oxyde/peroxyde is even more dangerous. In fact - this is how soap was made for centuries - just boil some fat in concentrated sodium hydroxyde and soon you will have some soap.
It's obvious why these workers have to wear special suits.
More fun stuff about sodium - check out the famous Sodium Party that Theodore Gray had a while back (or wikipedia)
None of the previous replies mention an important requirement - stopping the chain reaction is just half of the problem. The bigger problem is that the core is still generating lots of thermal energy days after you shutdown the reactor. You still need to actively cool the core for at least 1-2 weeks otherwise the core would eventually melt.
Why? Remember that in a nuclear reactor, heat comes from two different sources:
1) The primary heat source is the direct fission process (which generates around 170 MeV per fission in a U-235 reactor). This reaction is immediately stopped when you don't have a chain reaction anymore.
2) The secondary source is the decay process of fission products (around 15-20 MeV per fission if I remember correctly). These fission products are extremely radioactive (with half-life fron nanoseconds to days), and typically will decay into other products which can decay into others, etc. until you reach some compounds which have much longer half-lifes (weeks, months, years or more)
So, to conclude, even after you shutdown a reactor, you still have to dissipate significant heat (about 10-15% from the total heat generated) which can STILL melt the core. That's why you need sophisticated cooling systems that need to work in the eventuality of an accident.
>>> First the "Robot Saves Troops" story and now this. Pretty cool how robots are actually helping us nowadays.
/ 17/0226200&tid=216
No - this is exactly the same story, around the same incident at White Sands Missile Range in New Mexico. This story is a dupe.
http://hardware.slashdot.org/article.pl?sid=05/12
This specific story made me realize something on digg vs. shashdot comparisons. Usually digg.com is a good source for early news, something that Slashdot ceased to be some time ago. I go more frequently to digg.com these days to get the latest cool news.
c ting_the_soldiers_of_tomorrow
As an example, I saw this story a few days ago on digg.com (eight days ago, to be more exact).
http://www.digg.com/technology/Nano-armor_-_Prote
But here is the interesting fact: the story barely got any diggs, even though I found it out as a very interesting story. But here on Slashdot, the story makes the first page, thankfully... So interesting stories have better changes to show up on Slashdot after all!
I don't know, franly, but I am not sure about using tubes because as someone else pointed out, beta radiation (and gamma rays too) would ionize the rarefied gas inside the tube, therefore affecting the flow of electrons (in fact this is one of the principles behind various designs of radiation detectors). But probably it might work in some conditions.
Another solution would be to use hardened semiconductors, with much bigger gates, etc. For example, in space you have cosmic rays (which, BTW are much more energetic than nuclear-generated gamma rays). NASA is using hardened electronic components which are able to withstand the random ionization generated by cosmic rays.
Ionizing radiations (usually beta/gamma radiation) can affect materials in various ways. For example, an energetic gamma-ray photon (around 0.3 MeV for the Cobalt-60 spectrum) would cause partial ionization of Si atoms in traditional semiconductors. Since the n/p difference is extremely small in a single transistor, you just need a few thousand ionizations in it to make it unusable.
P.S. http://www.nlectc.org/training/nij2005/Conca.pdf - some interesting material there.
Where are my mod points when I need them? :-)
>>> We calculated that, if acetylene is reacting with the hydrogen gas to turn it back into methane, quite a bit of energy is being released. So that's our basis for saying there is something to eat on Titan. We don't know if there are any customers, but there's something on the menu.
This reaction doesn't make any sense. The C-C bond is much too stronger to be broken by a small release of energy done by the hydrogen absorbtion. At worst, this will generate etylene in the first step, and then ethane in the second step.
>>>> Index a mans fish and...
0 73
Hmm... now, where did I hear this?
http://channel9.msdn.com/ShowPost.aspx?PostID=104
You forgot: ...
5. Profit!
Just asking... it's funny when you see typos in headlines.
>>> The study estimated that individual doses would end up being very high, at 2.26 sieverts.
Interesting. However, that this is 2.26 sieverts for the total mission. Usually, you get nausea, etc as part of the acute radiation syndrome, assuming that you are getting those in a few hours.
... is to insure minimum time between failures (MTBF).
In this case, the engineers ensured that whatever components are broken in the shuttle, they will fall of BEFORE the launch.
Error-correction in quantum algorithms is actually the key issue in future development of quantum computing. And, not only that, but you have to come up with a correction algorithm where the complexity scales polynomially with the size of the system. Also,
o s-ndd112904.php
It is a hard problem - even if we have years of theoretical research, the first succesful experiment that probed the real error correction was done only few months ago (see Nature - Dec 1 2004), or http://www.eurekalert.org/pub_releases/2004-12/ni
>>> And for those with tinfoil hats- keep in mind that some assume that we don't get real info from NASA- such as those who say that gravity on the moon is much closer to the Earth's gravity, unlike what we are told, but this can't be released because it would throw a Geurilla Wrench into the theory of relativity....
Believe me - any aspiring scientist would LOVE to throw a Guerilla Wrench into the theory of relativity. How does a Nobel prize sounds to you?
I probably overreacted (given that you can buy today a 1 GB of DDR memory for less than $100). I agree - after all, if you have heavily executed code in the kernel module, then you better make sure that it stays in L1/(and especially L2) caches as much as possible.
>>> ZETA is a very fast operating system written from the ground up to get more out of your hardware than any other. With a true micro kernel is of only 640 KB and a 64-bit journalling filesystem to make things fly.
640kb? Who cares?
Yet another example of pixie-dust projects...
>>> The Korean site, unlike U.S. versions, was operated by another company, which Microsoft did not identify. Microsoft's own experts and Korean police were investigating, but Microsoft believes the computers were vulnerable because operators failed to apply necessary software patches, said Sohn, an MSN director.
Don't trust other companies to apply security patches for your site.
>>> Aluminum was not known as a metal 1,000 years ago
You will be surprised to hear that aluminum metal was found in a metal ornament found in a 1700 year old tomb in China.
http://www.metkos.com/aluminum.htm
This is one of the worst behchmark articles I read in a long time.
... 256K), or various requests combined.
What is missing is a systematic analysis of DISK performance in respect to various dimensions:
1) Pure disk read vs. pure disk write vs mixed I/O/
2) Sequential I/O vs random I/O vs. mixed
3) block size (512 bytes, 1K,
4) Does it matter when you have multiple RAID volumes vs. only one? (this matters especially for SW RAID)
5) Disk/LUN size.
Also, the performance numbers should include:
1) The average and max read/write time. Distribution patterns.
2) The average and max queue length in various workloads.
3) The predictability of these numbers. (which matters for SW RAID)
4) RAID recovery time
5) Performace numbers when the RAID set is broken (one disk is bad).
6) Performace numbers during RAID recovery (set rebuilding - i.e. after you replaced the bad disk with a good one).
It is also interesting to find out various I/O patterns for real-world deployments, for example a database, a file system, etc. Isolating the I/O pattern for common file system operations, or database deployemnts, and map them to the figures above.
And, one more thing - an administrator will likely deploy RAID for its main advantage - relatively good read performance combined with its low downtime when one disk goes bad. But there is a drawback - if one of the three disks goes bad, the performance will be severy affected. On a badly designed system, the performance drop might render the server unusable if it cannot stand up the continuous flow of requests. So it is very important to know the particular behavior during RAID recovery. This data is also missing from the article.
>>> I think PS/3 has the advantage and will eventually win. I'm surprised at the specs as original discussions on the machine had indicated it would be fitted with FOUR Cell processors, not one.
It's all about the relation with game publishers, the differences in terms of performance are insignifiant.
Remember that XBox was touted as much more powerful than PS2, however it didn't got enough market share...
A lawn mover that can mate? It's called a geese.