I'm not quite sure what you mean by your analogy of the physicist
I am not sure what you mean by analogy. Take a spectrograph of the suns incoming radiation, take spectrographs of the IR leaving the Earth under various temperatures. Take data on the how the major components (including Carbon Dioxide) of the earths atmosphere absorb various wavelengths of light. Give all this to a physicist, and ask them to estimate the temperature of the earth under various levels of CO2 in the atmosphere
If the information we drew from the correlation was wrong, which is what the 800 year gap suggests, then ALL the current models are completely worthless.
So you say. It sounds implausible to me that all the models are based on data from ice cores. It seems that Climate science is large enough that people would have used multiple different ways of estimating the effect of CO2 on temperatures. I don't see how Al Gore's movie provides any evidence that other models of global warming doesn't exist.
The chart I am referring to IS the basis for the belief that CO2 has a measurable effect on the temperature of our planet
How do you know this? It seems a physicist could easily do a simple simulation comparing the radiation hitting from the sun versus the radiation escaping through the greenhouse gases from the physical properties of those gases.
dealt with the 800 year gap and explanations on why it is there.
All I found was that there was a paper discussing this in 2007. I did not find any papers in response, although I didn't look very hard.
The entire global warming problem is contingent on the concept that an increase in CO2 leads to higher temperatures, and this is based on the data compiled into the nice chart that Al Gore displays and comments,
Al Gore's chart is hardly the basis of Climate research. It is well known that Carbon Dioxide is a Greenhouse Gas. It is clear there *are* greenhouse Gases, or the planet would be. It is also easy to test that CO2 allows the high energy radiation from the Sun in, but traps the low energy IR from the earth.
AFAICT the main question is, what will happen to all the carbon dioxide we release? Will it all be absorbed into plant matter? Or will it warm the planet enough to release more CO2 from the oceans which then warms the planet more which...
Of course this leaves the question, "Why does the planet heat up?" to be answered, and while the data is much more limited, there seems to be a very strong correlation between solar activity and global temperature.
A quick google search shows up: "Researchers argue over whether or not solar variations play a major role in determining present-day observed climate change. [41]... In their Third Assessment Report, the IPCC state that the measured magnitude of recent solar variation is much smaller than the amount of predicted climate change due to greenhouse gases." -- Wikipedia
Well being a Slashdot reader and all I could barely be bothered RTFA. I certainly can't be bothered spending 3 years to get even a undergraduate level understanding of Climate Science. So all I really know is that both sides can draw pretty graphs. No matter how much evidence is gathered neither side's pretty graphs will go away. However pretty much every scientific institution seems to take the threat of global warming pretty seriously. So I'd take it pretty seriously as well.
I am not doing science here. But I did not claim to be a climate scientist. I am more like the child who is told by their parent that a pot is hot, and thinks "maybe touching the pot isn't such a good idea".
That's funny. I was just reading a New Scientist article by a meteorologist specializing in computer models of hurricane activity complaining about how hurricane modeling is so often mistaken by the press for general climatology models, when in truth none of the general climatology models in use make predictions on small enough of a scale to predict a given hurricane season.
Computer models of hurricane activity are like trying to figure where a drunk crashes. Climate research is more like saying `Hmm, maybe having "one for the road isn't such a great idea afterall"',
You mean to say the US actually complied with the UN resolutions djh mentioned? Or has ever complied with any UN resolution they didn't like for that matter?
Indeed. Most of my Apple Basic software running on a 1 MHz 6502 was damn fast. In some important ways scripted code is often much faster. If you want to change a line of C++ code: "I'll have to change a line of code. Oh no, I'll have to wait several minutes to relink correctly, then I'll have restart the App and get it back to this point". In scripted code: "Changes line of code. Hits retry."
Even in Linux, most distro's don't have full filesystems built into the kernel. Instead they only build in a tiny in-memory fs that allows them to read an initrd. This means that they can have virtually any filesystem as a root filesystem without having to compile every conceivable filesystem into their general purpose kernel.
It is also possible to avoid ever booting in the way Linux machines boot. Instead, the boot process could act like the hibernate/resume functionality of Linux. So instead of loading programs into the address space from a filesystem, we simply read the resulting address space from disk. After all, some embedded devices don't need to ever use a filesystem, so in these cases loading a fs would be a waste of resources.
Further investigation into the cause of dataloss under the Ext4 Filesystem has revealed that it is not the fault of Application Developers, Ext4, nor even the evil POSIX manual of Doom. Its turns out that it Obama is so corrupt that he has caused major dataloss all around the nation. There! At least I'm an *on topic* Troll. Was that so hard?
It doesn't matter how long the delay is, so long as the OS doesn't reorder "delete old file" to occur before the "create new file". In ext3 in ordered mode, the OS doesn't reorder writes, so you are fine. (unless your hard-disk reorders writes)
From your link: "If you want a platform independent program, avoid fsync". It seems unfortunate that OS implementers have so often interpreted this as "If you want a platform independent program, kiss your data goodbye."
They talk about what to do when a bug is discovered. My understanding is that beta testing may result in thousands of crash reports. Clearly you'll want to prioritize fixing the exploitable crashes before the non-exploitable ones. It seems this software is to help you do that, although the article is short on technical detail.
1. POSIX is an API. It tries not to force the filesystem into being anything at all. So, for instance, you can write a filesystem that waits to do writes more efficiently to cut down on the wear of SSDs.
POSIX explicitly requires that data be flushed to disk when fsync is called. This wears out SSDs and forces HDDs to spin up wearing out. So while you could write an fs that ignores fsyncs (MacOS X more-or-less does this), that fs would be not be POSIX compliant.
So, if your application wants to "delete this file after this other file has been deleted, without triggering a spinup", using fsync is *explicitly* wrong. Under *any* POSIX compliant fs this will force an spinup.
If you do not use an fsck, your app will be compatible with at least some POSIX compliant fs, including ext3 with data=ordered.
2. Ext3 has a max 5 second delay. That means this bug exists in Ext3 as well.
I understand that when running on battery this is usually increased to 15 seconds which is probably enough to stop your harddisk dieing before its time.
4. Atomicity does not guarantee the filesystem be synchronized with cache. It means that during the update no other process can alter the affected file and that after the update the change will be seen by all other processes.
Good. Because we not want the filesystem to be syncronized with disk (cache?). This forces a spin up. All we want is for atomicity to be preserved during a crash; this does not require a spin up. Note, for example, that if the drive does not spin up before the crash then the neither will the old file be deleted nor will the new file be written.
Blaming the application developers is a bit rich. In EXT3 fsync was not only not necessary, it also could cause the system to freeze for 30 seconds, hence userland developers for Linux avoided fsync unless the data was not only just important but *really* *really* important.
Also application developers have to make many assumptions not explicitly spelt out in the POSIX specification, e.g. POSIX does not explicitly specify, e.g. that you machine has more than 16 bytes of RAM, that there is no "rm -rf/" in your initscripts etc. It is stupid to trumpet a new delayed allocation scheme, and then say "unless you explicitly disable it, your filesystem may enter a inconsistent state", so make sure that you always disable it or its *your* code thats buggy.
I also salute Mr. Tso... for recanting and fixing the damn bug. There is a more throughout discussion here.
The range of "habitable temperatures" for humans probably depends on the human and what temperature they are used to.
It reaches 45C/113F here occasionally, goes over 40C/104F regularly, and I'm still alive. 100F/36 Degrees is quite pleasant for going to the beach or sitting on the shade with a drink... not so pleasant for working and by law manual laborers do not need to work at 40C/104F and above.
The photos linked to in the article couldn't be really considered hate speech... hate speech against whom? Not the fetuses, as the site is "pro-life". If publishing photos of dead fetuses is hate speech against pro-choicers then we may as well tear up free speech. (Technically the ACMA censors offensive images as well as hate speech, but still I don't consider the existance of such images offensive if they are not being waved in my face)
Yes chrome GUI is OK, but the real advantage is that Chrome has an decent architecture so that a crash usually doesn't crash the entire browser (this may also have security benefits, as I understand Google sandboxes the tabs). See: http://www.google.com/chrome/intl/en/features.html#
You can't do that as a mod to firefox (You'd have to do it as a mod to Emacs instead;)
Also, Wine would need more context switches than either Linux or Windows. If you are running a single process you usually switch between at most two contexts, your userspace process and the kernel. However since the functionality of the Linux kernel isn't a perfect match for the Windows kernel, Wine needs an additional context/process, the wineserver, to provide this functionality. So context switches wouldn't benefit wine over plain Linux.
I use a large pagefile so that I can use Suspend-to-Swap. I occasionally do swap out most of my 2GB of memory when running stress tests, but I don't need to swap all of it back in at once so my system remains usable. In any case, since 8GB of regular disk space is dirt cheap there is little need to change this behavior (although swapfiles may make more sense).The strongest argument for disabling swap on a regular harddisk would be to force the OOM killer to kill a misbehaving process that suddenly wants to allocate all memory, but there are other ways of doing this.
Using a fork() call is usually simpler and safer than than multi-threading (on an OS that supports it), and you don't need to explicitly make a copy of the data.
Slashdot Mirror
I'm not quite sure what you mean by your analogy of the physicist
I am not sure what you mean by analogy. Take a spectrograph of the suns incoming radiation, take spectrographs of the IR leaving the Earth under various temperatures. Take data on the how the major components (including Carbon Dioxide) of the earths atmosphere absorb various wavelengths of light. Give all this to a physicist, and ask them to estimate the temperature of the earth under various levels of CO2 in the atmosphere
If the information we drew from the correlation was wrong, which is what the 800 year gap suggests, then ALL the current models are completely worthless.
So you say. It sounds implausible to me that all the models are based on data from ice cores. It seems that Climate science is large enough that people would have used multiple different ways of estimating the effect of CO2 on temperatures. I don't see how Al Gore's movie provides any evidence that other models of global warming doesn't exist.
The chart I am referring to IS the basis for the belief that CO2 has a measurable effect on the temperature of our planet
How do you know this? It seems a physicist could easily do a simple simulation comparing the radiation hitting from the sun versus the radiation escaping through the greenhouse gases from the physical properties of those gases.
dealt with the 800 year gap and explanations on why it is there.
All I found was that there was a paper discussing this in 2007. I did not find any papers in response, although I didn't look very hard.
I find that Global Warming has become less of a science and more of a religious movement.
I don't know your (ex-)friends but isn't it possible it is backed by solid science and also has crazy zealots?
There are people whom I work with who actually have lost sleep.
Which increases the CO2 they exhale, the selfish bastards.
even Gravity is a theory in scientific terms, not a fact.
I still won't jump off the 99th story. Sorry.
When you attempt to silence the scientific debate in a venue such as this,
Wait, there is scientific debate on Slashdot? I just see lots of "you are unscientific... no you are unscientific".
Why work to improve a technology if it's simply going to be imposed on the public anyway right?
So that the public will buy your solar panels rather than the ones from ACME corp that cost 99c more?
The entire global warming problem is contingent on the concept that an increase in CO2 leads to higher temperatures, and this is based on the data compiled into the nice chart that Al Gore displays and comments,
Al Gore's chart is hardly the basis of Climate research. It is well known that Carbon Dioxide is a Greenhouse Gas. It is clear there *are* greenhouse Gases, or the planet would be. It is also easy to test that CO2 allows the high energy radiation from the Sun in, but traps the low energy IR from the earth.
AFAICT the main question is, what will happen to all the carbon dioxide we release? Will it all be absorbed into plant matter? Or will it warm the planet enough to release more CO2 from the oceans which then warms the planet more which ...
Of course this leaves the question, "Why does the planet heat up?" to be answered, and while the data is much more limited, there seems to be a very strong correlation between solar activity and global temperature.
A quick google search shows up: "Researchers argue over whether or not solar variations play a major role in determining present-day observed climate change. [41] ... In their Third Assessment Report, the IPCC state that the measured magnitude of recent solar variation is much smaller than the amount of predicted climate change due to greenhouse gases." -- Wikipedia
Well being a Slashdot reader and all I could barely be bothered RTFA. I certainly can't be bothered spending 3 years to get even a undergraduate level understanding of Climate Science. So all I really know is that both sides can draw pretty graphs. No matter how much evidence is gathered neither side's pretty graphs will go away. However pretty much every scientific institution seems to take the threat of global warming pretty seriously. So I'd take it pretty seriously as well.
I am not doing science here. But I did not claim to be a climate scientist. I am more like the child who is told by their parent that a pot is hot, and thinks "maybe touching the pot isn't such a good idea".
CO2 levels have never been so high as they are now throughout recorded history
http://www.junkscience.com/MSU_Temps/historical_CO2.html
Technically those would be prehistoric times.
That's funny. I was just reading a New Scientist article by a meteorologist specializing in computer models of hurricane activity complaining about how hurricane modeling is so often mistaken by the press for general climatology models, when in truth none of the general climatology models in use make predictions on small enough of a scale to predict a given hurricane season.
Computer models of hurricane activity are like trying to figure where a drunk crashes. Climate research is more like saying `Hmm, maybe having "one for the road isn't such a great idea afterall"',
You mean to say the US actually complied with the UN resolutions djh mentioned? Or has ever complied with any UN resolution they didn't like for that matter?
Indeed. Most of my Apple Basic software running on a 1 MHz 6502 was damn fast. In some important ways scripted code is often much faster. If you want to change a line of C++ code: "I'll have to change a line of code. Oh no, I'll have to wait several minutes to relink correctly, then I'll have restart the App and get it back to this point". In scripted code: "Changes line of code. Hits retry."
Even in Linux, most distro's don't have full filesystems built into the kernel. Instead they only build in a tiny in-memory fs that allows them to read an initrd. This means that they can have virtually any filesystem as a root filesystem without having to compile every conceivable filesystem into their general purpose kernel.
It is also possible to avoid ever booting in the way Linux machines boot. Instead, the boot process could act like the hibernate/resume functionality of Linux. So instead of loading programs into the address space from a filesystem, we simply read the resulting address space from disk. After all, some embedded devices don't need to ever use a filesystem, so in these cases loading a fs would be a waste of resources.
Further investigation into the cause of dataloss under the Ext4 Filesystem has revealed that it is not the fault of Application Developers, Ext4, nor even the evil POSIX manual of Doom. Its turns out that it Obama is so corrupt that he has caused major dataloss all around the nation. There! At least I'm an *on topic* Troll. Was that so hard?
It doesn't matter how long the delay is, so long as the OS doesn't reorder "delete old file" to occur before the "create new file". In ext3 in ordered mode, the OS doesn't reorder writes, so you are fine. (unless your hard-disk reorders writes)
From your link: "If you want a platform independent program, avoid fsync". It seems unfortunate that OS implementers have so often interpreted this as "If you want a platform independent program, kiss your data goodbye."
They talk about what to do when a bug is discovered. My understanding is that beta testing may result in thousands of crash reports. Clearly you'll want to prioritize fixing the exploitable crashes before the non-exploitable ones. It seems this software is to help you do that, although the article is short on technical detail.
1. POSIX is an API. It tries not to force the filesystem into being anything at all. So, for instance, you can write a filesystem that waits to do writes more efficiently to cut down on the wear of SSDs.
POSIX explicitly requires that data be flushed to disk when fsync is called. This wears out SSDs and forces HDDs to spin up wearing out. So while you could write an fs that ignores fsyncs (MacOS X more-or-less does this), that fs would be not be POSIX compliant.
So, if your application wants to "delete this file after this other file has been deleted, without triggering a spinup", using fsync is *explicitly* wrong. Under *any* POSIX compliant fs this will force an spinup.
If you do not use an fsck, your app will be compatible with at least some POSIX compliant fs, including ext3 with data=ordered.
2. Ext3 has a max 5 second delay. That means this bug exists in Ext3 as well.
I understand that when running on battery this is usually increased to 15 seconds which is probably enough to stop your harddisk dieing before its time.
4. Atomicity does not guarantee the filesystem be synchronized with cache. It means that during the update no other process can alter the affected file and that after the update the change will be seen by all other processes.
Good. Because we not want the filesystem to be syncronized with disk (cache?). This forces a spin up. All we want is for atomicity to be preserved during a crash; this does not require a spin up. Note, for example, that if the drive does not spin up before the crash then the neither will the old file be deleted nor will the new file be written.
Blaming the application developers is a bit rich. In EXT3 fsync was not only not necessary, it also could cause the system to freeze for 30 seconds, hence userland developers for Linux avoided fsync unless the data was not only just important but *really* *really* important.
Also application developers have to make many assumptions not explicitly spelt out in the POSIX specification, e.g. POSIX does not explicitly specify, e.g. that you machine has more than 16 bytes of RAM, that there is no "rm -rf /" in your initscripts etc. It is stupid to trumpet a new delayed allocation scheme, and then say "unless you explicitly disable it, your filesystem may enter a inconsistent state", so make sure that you always disable it or its *your* code thats buggy.
I also salute Mr. Tso... for recanting and fixing the damn bug. There is a more throughout discussion here.
The range of "habitable temperatures" for humans probably depends on the human and what temperature they are used to.
It reaches 45C/113F here occasionally, goes over 40C/104F regularly, and I'm still alive. 100F/36 Degrees is quite pleasant for going to the beach or sitting on the shade with a drink... not so pleasant for working and by law manual laborers do not need to work at 40C/104F and above.
Oh. I thought he liked just liked to pick 'em young :P
I prefer fetuses that are those sexy... what are they called... nappies. Leaves more to the imagination. Each to their own I guess. ;)
The photos linked to in the article couldn't be really considered hate speech ... hate speech against whom? Not the fetuses, as the site is "pro-life". If publishing photos of dead fetuses is hate speech against pro-choicers then we may as well tear up free speech. (Technically the ACMA censors offensive images as well as hate speech, but still I don't consider the existance of such images offensive if they are not being waved in my face)
You find photos of dead fetuses remotely pornographic? How?
You can't do that as a mod to firefox (You'd have to do it as a mod to Emacs instead ;)
Also, Wine would need more context switches than either Linux or Windows. If you are running a single process you usually switch between at most two contexts, your userspace process and the kernel. However since the functionality of the Linux kernel isn't a perfect match for the Windows kernel, Wine needs an additional context/process, the wineserver, to provide this functionality. So context switches wouldn't benefit wine over plain Linux.
I use a large pagefile so that I can use Suspend-to-Swap. I occasionally do swap out most of my 2GB of memory when running stress tests, but I don't need to swap all of it back in at once so my system remains usable. In any case, since 8GB of regular disk space is dirt cheap there is little need to change this behavior (although swapfiles may make more sense).The strongest argument for disabling swap on a regular harddisk would be to force the OOM killer to kill a misbehaving process that suddenly wants to allocate all memory, but there are other ways of doing this.
Using a fork() call is usually simpler and safer than than multi-threading (on an OS that supports it), and you don't need to explicitly make a copy of the data.