There's a form of deduplication supported by the Linux kernel, if you use the logical volume manager. If you create base LVM device, and then create a snapshot of that device, the snapshot only requires sufficient real estate on the host physical volume to store the diffs between the snapshot and the base. You can use this for "freezing" a file system to do back-ups, or for incremental back-ups, or whatever.
My rather limited experience with this is that, if you have more than a few snapshots on a base device, your write performance degrades very raplidy. There's also a hard limit of 255 snapshots per device.
You can also do file-based deduplication with the "rsnapshot" tool, which has been available for many years.
Also also, I haven't kept up, but I seem to recall that ZFS for linux was promising this as a major selling point.
I did something like this, although I had been the informal "back-up" admin for a while before I took over. Even so, the take-over was very sudden, and I quickly discovered there were whole facets of the system I didn't even know existed.
My solution was to pick one major sub-unit at a time, and migrate it to a system that I understood -- you probably have to do this anyways, since you have to do upgrades on your software, use that as an opportunity to get a grip on the system in question. In my case, the first choice was easy, the primary SAN host blew up about a month into the project. My users had a really lousy day that day, but 24 hours later, I had an object lesson in the importance of back-ups, and by God I knew how the (new) system worked.
> Have a mechanism that can quickly raise a physical barrier (nice thick steel plate or something) in front of where you're supposed to stop at the red. The barrier lowers when it's green.
From what I've seen where I llive, you don't need anything anywhere near that drastic. People here will slow down to 2 mph and carefully and gingerly make their way over three-inch speed bumps.
So, have *five*-inch mechanical speed bumps at the stop lines, synchronized with the lights. The drivers' brains will explode as they struggle to decide which animal urge to follow, to display their status by blasting through the light, or protect their property by stopping.
Basic Ohm's law -- the resistive loss through a DC wire is the voltage drop across the wire, times the current through the wire. But the voltage drop across the wire is proportional to the current, it's just I*R, so the total power dissipated in the wire itself (i.e. not transferred to the load) is I*I*R. So, you want the current going to the load to be as small as possible. But, of course, the load still needs to get all the power it needs, so the operating voltage (which is distinct from the through-the-wire voltage *drop*, of course) needs to be higher if the current is lower.
So, high operating voltages reduce distribution losses.
The same analysis works for AC too, and is the reason that trans-continental transmission wires have such crazy-high voltages. AC has additional losses due to radiation and induction, of course.
Seconding this. The goal of the process is 100% certainty that the data does not become available to anyone ever again. The fact that one of the reasons you want an alternative is because it's expensive to buy new drives is a gigantic strike against you -- you've basically admitted that you want to re-use the drives. Nobody in the government is going to approve a plan that involves the re-use of drives that have had sensitive information on them. And, of course, any plan that doesn't involve drive re-use *should* include drive destruction, as a strategy to ensure re-use does not occur.
This is basically the same mentality that mandates air-gapping critical control systems to isolate them from the network. It's true that there are more convenient and less drastic schemes which, if operated correctly, provide the same protection. But if the goal is 100% certainty, then "if operated correctly" is too big of an "if".
Well, the cable companies are not the only possibility.
There's competing streaming video from Amazon, which can stream both rentals and streaming versions of DVDs you buy from them, and audio. It's also not hard to imagine a significant expansion of video for iTunes. Amazon and Apple seem to have good relationships with their customers, so this is a serious issue.
There's also Hulu+, and it's pretty clear that Google is trying to integrate YouTube movie streaming into G+.
This seems like a pretty narrow concept of freedom. I'm kind of uncomfortable with self-driving cars myself, I have the control-freak instinct, I currently drive a stick-shift mostly for that reason. But it really is pretty hard to argue against either safety or practicality of self-driving cars.. I'm assuming that the self-driving car really is more like a taxi than a bus, in that if I decide half-way to my destination that I want a different destination, I can just make it so, and that will be that, and furthermore that if I want to take the scenic route down along the creek instead of the freeway, I can get that too.
So, I can still pick my time of departure, my route, and my destination, and change my mind in mid-drive, only my freedom to operate the vehicle has been removed. Yeah, it bugs me a bit, but I don't know if I'm ready to die for it.
And where's the line? In my city, it's hopelessly impractical (and maybe illegal) for me to ride a horse to and from work. Is that an unacceptable infringement on freedom of movement? Should I die for that one too?
Distantly related to an idea I saw being batted around years ago, which I liked very much -- make the House of Representatives itself work this way. Serving your district in the House is like jury duty, you get a summons, you serve for a year, and then you're done.
It's fun to think about, but the problem is that if the members (of sanity-check or my wacky HoR) are known to be short-timers, their privileges will end up being suborned by the permanent staff, who will have the institutional memory needed to work the system. And then you're back to square one. See the British TV comedy "Yes, Minister" for a vivid illustration of the dynamic.
So you probably know this already, but for the benefit of similarly-minded but less-knowledgeable readers, there are many desktop environments for Linux -- open source breeds choice, after all.
We're mostly a KDE shop where I work, but there are users using xfce, fvwm, and xmonad here, and one who swears by gnome, but launches it from KDM, because our system has its big warning banner set up for KDM but not GDM or XDM.
So if they end-of-life gnome2 out from under you, you still have options.
Is it my imagination, or does nuclear-power advocacy have a moving-goalposts problem? For myself, I guess I'm like most folks here, I'd love it if there were a technologically advanced carbon-free power source we could all use, so we could all be techno-optimists, and superficially, it seems that nuclear power could be that power source.
But at this point, even fission-power advocates seem to be betting the farm on future designs, rather than trying to convince anyone that any actually operational system is currently being operated safely. This comment thread is worse -- we've heard for a while that thorium reactors will be better, but now that someone's actually building one, it turns out to be the wrong kind of thorium reactor.
I want this to work, but I'm having trouble shaking the sense that fission power is only safe when it's confined to PowerPoint slides, and becomes dangerous when it collides with reality.
Keen! That's cool, I (obviously) didn't know that.
Also, having finally RTFA, I see that they've already met my other objection -- the way their system actually works is, it measures the *force* applied by the lever arm, and applies the same force at the brake pad. Of course this means you can't feel the sharply rising force when you really hit the binders, but it does mean that the reaction force of the lever really is (proportional to) the normal force on the brake pad.
To be useful, this would probably have to include some kind of force-feedback, so you know how hard you're pressing. You can't deduce this from lever position, because the brake pads wear down over their life. So, you'll need a motor in the handle, as well as in the brake itself.
On the up-side, it will mean you can incorporate front brakes on those BMX stunt bikes where some of the tricks involve spinning the handlebars all the way around.
Also also: "brake" == device for slowing something down, or the process or effect of slowing something down; "break" == to damage or destroy something, the act of destroying something, or a gap or discontinuity. FYI.
> As for the story, teaching kids to question things for themselves spells the end of the liberal state. For then you start asking just where your money goes, as just one example...
That thing cuts both ways, you know. They might start asking where their money comes from.
So the whole awesomeness of the ISS is, you know, people in space. It costs a bazillion extra dollars to get them there, but they're mentally flexible and can innovate on short time-scales to deal with unexpected contingencies. That's why it's worth it to fly thousands of extra pounds of life-support equipment, not to mention all the extra trips to ferry up human-needed supplies, into this highly weight-constrained environment -- because there's a lot that humans can do that robots either can't do on a useful time-scale, or can't do at all.
And now we're putting a humanoid robot on the ISS? So, what, we can enjoy the comparative inflexibility of an automated system with the bulk and awkwardness of the humanoid form, and as a bonus, it doesn't even need the billion-dollar life-support system at all?
That's pretty cool, actually -- laser-induced fusion is reasonably well established, and dumping neutrons into an otherwise subcritical chunk of Thorium sounds like it might even be half-way safe.
I'm amazed anyone could get that from the articles, though -- I read them reasonably closely, and all they ever said was that they "heated" the Thorium, and that there were lasers involved, and pulses of heat.
I'm surprised this hasn't been mentioned yet, but this is yet another compromise and fake-out non-achievement for this administration -- he back-pedaled from his own compromise number, and then set the deadline to be fourteen years away.
The administration got what they wanted, which was a nice green press release.
The car makers got what they wanted, a toothless rule -- they know that, some time during those 14 years, a Republican administration will revoke the requirement, once the car-industry lobbyists clarify how compliance will impact their ability to make campaign donations.
I was on an H1-B for a while (in academic research, not software development, as it happens), and was puzzled at the time by the requirement to pay US Social Security taxes -- the H1-B is a visitor visa, not an immigrant visa, it's time-limited, and when it runs out, the assumption is that the individual will return to their home country. I would imagine that very few H1-B visa holders ever recover this money, so it's effectively a tax on the employer, paid into the SS trust fund.
Having H1-B holders not make SS contributions seems reasonable to me -- if you want to tax H1-B activity, you can always just raise the fees for the visa itself, to get the same effect -- but having only Indian H1-B holders be exempt from the SS contribution just seems bizarre.
The summary is unclear, but on the grounds of basic common sense, I hope that pressure and lobbying went nowhere.
So this is where I am compelled to insert my rant about population -- there is a very well known, almost fool-proof scheme for reducing the birth rate of any society, but it is at odds with may cultures' traditional values, and it has a generational lag-time, so it requires both courage and vision. For this reason, it is not widely adopted.
The strategy is this: Send girls to school.
If women are empowered culturally, and have expectations of building their own lives and careers, their preferences regarding children change. If they are taught to think independently, they will choose partners with similar preferences, and the birth rate will fall.
Every first-world country has already completed this trajectory, and in many cases, it was wrenching, and the social costs were high, but in the end, these societies attained a very high standard of living with a low birth rate.
The good news is, in most societies in the world, this is already underway. Increasing wealth and the perpetually-rising middle class helps a lot with this. It's likely that, in 100 years, we will be wringing our hands over how to continue to grow the economy in the face of a shrinking global population.
What I wrote is technically true (it's not a legally binding part of the "highest law", i.e. the Constittuion), and that was my main point, but I didn't actually know it was an act of the US Congress.
I know it was adopted by the pre-1787 "United States in Congress Assembled", but if it's in the US Code, then presumably it was also adopted by the post-1787 Congress, i.e. the one constituted by the Constitution.
> last time I read the document, it began with "WE HOLD THESE TRUTHS TO BE SELF-EVIDENT". *Self-evident*...
Read it again. That line is not in the US constitution, it's in the declaration of independence. The sentiment definitely informs all of the founding documents, but it's far from a legally-binding portion of the highest law of the US.
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There's a form of deduplication supported by the Linux kernel, if you use the logical volume manager. If you create base LVM device, and then create a snapshot of that device, the snapshot only requires sufficient real estate on the host physical volume to store the diffs between the snapshot and the base. You can use this for "freezing" a file system to do back-ups, or for incremental back-ups, or whatever.
My rather limited experience with this is that, if you have more than a few snapshots on a base device, your write performance degrades very raplidy. There's also a hard limit of 255 snapshots per device.
You can also do file-based deduplication with the "rsnapshot" tool, which has been available for many years.
Also also, I haven't kept up, but I seem to recall that ZFS for linux was promising this as a major selling point.
I'm not sure I follow -- your position is that there was not a dramatic shift in the climate at the end of the last ice age?
When you say "end of the last ice age", what do you mean?
I did something like this, although I had been the informal "back-up" admin for a while before I took over. Even so, the take-over was very sudden, and I quickly discovered there were whole facets of the system I didn't even know existed.
My solution was to pick one major sub-unit at a time, and migrate it to a system that I understood -- you probably have to do this anyways, since you have to do upgrades on your software, use that as an opportunity to get a grip on the system in question. In my case, the first choice was easy, the primary SAN host blew up about a month into the project. My users had a really lousy day that day, but 24 hours later, I had an object lesson in the importance of back-ups, and by God I knew how the (new) system worked.
> Have a mechanism that can quickly raise a physical barrier (nice thick steel plate or something) in front of where you're supposed to stop at the red. The barrier lowers when it's green.
From what I've seen where I llive, you don't need anything anywhere near that drastic. People here will slow down to 2 mph and carefully and gingerly make their way over three-inch speed bumps.
So, have *five*-inch mechanical speed bumps at the stop lines, synchronized with the lights. The drivers' brains will explode as they struggle to decide which animal urge to follow, to display their status by blasting through the light, or protect their property by stopping.
Basic Ohm's law -- the resistive loss through a DC wire is the voltage drop across the wire, times the current through the wire. But the voltage drop across the wire is proportional to the current, it's just I*R, so the total power dissipated in the wire itself (i.e. not transferred to the load) is I*I*R. So, you want the current going to the load to be as small as possible. But, of course, the load still needs to get all the power it needs, so the operating voltage (which is distinct from the through-the-wire voltage *drop*, of course) needs to be higher if the current is lower.
So, high operating voltages reduce distribution losses.
The same analysis works for AC too, and is the reason that trans-continental transmission wires have such crazy-high voltages. AC has additional losses due to radiation and induction, of course.
... is here.
Seconding this. The goal of the process is 100% certainty that the data does not become available to anyone ever again. The fact that one of the reasons you want an alternative is because it's expensive to buy new drives is a gigantic strike against you -- you've basically admitted that you want to re-use the drives. Nobody in the government is going to approve a plan that involves the re-use of drives that have had sensitive information on them. And, of course, any plan that doesn't involve drive re-use *should* include drive destruction, as a strategy to ensure re-use does not occur.
This is basically the same mentality that mandates air-gapping critical control systems to isolate them from the network. It's true that there are more convenient and less drastic schemes which, if operated correctly, provide the same protection. But if the goal is 100% certainty, then "if operated correctly" is too big of an "if".
Well, the cable companies are not the only possibility.
There's competing streaming video from Amazon, which can stream both rentals and streaming versions of DVDs you buy from them, and audio. It's also not hard to imagine a significant expansion of video for iTunes. Amazon and Apple seem to have good relationships with their customers, so this is a serious issue.
There's also Hulu+, and it's pretty clear that Google is trying to integrate YouTube movie streaming into G+.
This seems like a pretty narrow concept of freedom. I'm kind of uncomfortable with self-driving cars myself, I have the control-freak instinct, I currently drive a stick-shift mostly for that reason. But it really is pretty hard to argue against either safety or practicality of self-driving cars.. I'm assuming that the self-driving car really is more like a taxi than a bus, in that if I decide half-way to my destination that I want a different destination, I can just make it so, and that will be that, and furthermore that if I want to take the scenic route down along the creek instead of the freeway, I can get that too.
So, I can still pick my time of departure, my route, and my destination, and change my mind in mid-drive, only my freedom to operate the vehicle has been removed. Yeah, it bugs me a bit, but I don't know if I'm ready to die for it.
And where's the line? In my city, it's hopelessly impractical (and maybe illegal) for me to ride a horse to and from work. Is that an unacceptable infringement on freedom of movement? Should I die for that one too?
Distantly related to an idea I saw being batted around years ago, which I liked very much -- make the House of Representatives itself work this way. Serving your district in the House is like jury duty, you get a summons, you serve for a year, and then you're done.
It's fun to think about, but the problem is that if the members (of sanity-check or my wacky HoR) are known to be short-timers, their privileges will end up being suborned by the permanent staff, who will have the institutional memory needed to work the system. And then you're back to square one. See the British TV comedy "Yes, Minister" for a vivid illustration of the dynamic.
So you probably know this already, but for the benefit of similarly-minded but less-knowledgeable readers, there are many desktop environments for Linux -- open source breeds choice, after all.
We're mostly a KDE shop where I work, but there are users using xfce, fvwm, and xmonad here, and one who swears by gnome, but launches it from KDM, because our system has its big warning banner set up for KDM but not GDM or XDM.
So if they end-of-life gnome2 out from under you, you still have options.
Is it my imagination, or does nuclear-power advocacy have a moving-goalposts problem? For myself, I guess I'm like most folks here, I'd love it if there were a technologically advanced carbon-free power source we could all use, so we could all be techno-optimists, and superficially, it seems that nuclear power could be that power source.
But at this point, even fission-power advocates seem to be betting the farm on future designs, rather than trying to convince anyone that any actually operational system is currently being operated safely. This comment thread is worse -- we've heard for a while that thorium reactors will be better, but now that someone's actually building one, it turns out to be the wrong kind of thorium reactor.
I want this to work, but I'm having trouble shaking the sense that fission power is only safe when it's confined to PowerPoint slides, and becomes dangerous when it collides with reality.
Keen! That's cool, I (obviously) didn't know that.
Also, having finally RTFA, I see that they've already met my other objection -- the way their system actually works is, it measures the *force* applied by the lever arm, and applies the same force at the brake pad. Of course this means you can't feel the sharply rising force when you really hit the binders, but it does mean that the reaction force of the lever really is (proportional to) the normal force on the brake pad.
To be useful, this would probably have to include some kind of force-feedback, so you know how hard you're pressing. You can't deduce this from lever position, because the brake pads wear down over their life. So, you'll need a motor in the handle, as well as in the brake itself.
On the up-side, it will mean you can incorporate front brakes on those BMX stunt bikes where some of the tricks involve spinning the handlebars all the way around.
Also also: "brake" == device for slowing something down, or the process or effect of slowing something down; "break" == to damage or destroy something, the act of destroying something, or a gap or discontinuity. FYI.
You sure about that? Don't you know what a rhombus is?
> As for the story, teaching kids to question things for themselves spells the end of the liberal state. For then you start asking just where your money goes, as just one example...
That thing cuts both ways, you know. They might start asking where their money comes from.
> If you do use auto update...seriously, what could break?
FF5 broke my employer-mandated SSL VPN plug-in, which made me unable to telecommute.
They had a fix deployed about five weeks later...
So can you rent the botnet, and run a program that disinfects the botnet systems? Seems like that'd be a nice bit of white-hattery...
So the whole awesomeness of the ISS is, you know, people in space. It costs a bazillion extra dollars to get them there, but they're mentally flexible and can innovate on short time-scales to deal with unexpected contingencies. That's why it's worth it to fly thousands of extra pounds of life-support equipment, not to mention all the extra trips to ferry up human-needed supplies, into this highly weight-constrained environment -- because there's a lot that humans can do that robots either can't do on a useful time-scale, or can't do at all.
And now we're putting a humanoid robot on the ISS? So, what, we can enjoy the comparative inflexibility of an automated system with the bulk and awkwardness of the humanoid form, and as a bonus, it doesn't even need the billion-dollar life-support system at all?
Genius.
That's pretty cool, actually -- laser-induced fusion is reasonably well established, and dumping neutrons into an otherwise subcritical chunk of Thorium sounds like it might even be half-way safe.
I'm amazed anyone could get that from the articles, though -- I read them reasonably closely, and all they ever said was that they "heated" the Thorium, and that there were lasers involved, and pulses of heat.
Lots of engineering left to do, though.
I'm surprised this hasn't been mentioned yet, but this is yet another compromise and fake-out non-achievement for this administration -- he back-pedaled from his own compromise number, and then set the deadline to be fourteen years away.
The administration got what they wanted, which was a nice green press release.
The car makers got what they wanted, a toothless rule -- they know that, some time during those 14 years, a Republican administration will revoke the requirement, once the car-industry lobbyists clarify how compliance will impact their ability to make campaign donations.
I was on an H1-B for a while (in academic research, not software development, as it happens), and was puzzled at the time by the requirement to pay US Social Security taxes -- the H1-B is a visitor visa, not an immigrant visa, it's time-limited, and when it runs out, the assumption is that the individual will return to their home country. I would imagine that very few H1-B visa holders ever recover this money, so it's effectively a tax on the employer, paid into the SS trust fund.
Having H1-B holders not make SS contributions seems reasonable to me -- if you want to tax H1-B activity, you can always just raise the fees for the visa itself, to get the same effect -- but having only Indian H1-B holders be exempt from the SS contribution just seems bizarre.
The summary is unclear, but on the grounds of basic common sense, I hope that pressure and lobbying went nowhere.
So this is where I am compelled to insert my rant about population -- there is a very well known, almost fool-proof scheme for reducing the birth rate of any society, but it is at odds with may cultures' traditional values, and it has a generational lag-time, so it requires both courage and vision. For this reason, it is not widely adopted.
The strategy is this: Send girls to school.
If women are empowered culturally, and have expectations of building their own lives and careers, their preferences regarding children change. If they are taught to think independently, they will choose partners with similar preferences, and the birth rate will fall.
Every first-world country has already completed this trajectory, and in many cases, it was wrenching, and the social costs were high, but in the end, these societies attained a very high standard of living with a low birth rate.
The good news is, in most societies in the world, this is already underway. Increasing wealth and the perpetually-rising middle class helps a lot with this. It's likely that, in 100 years, we will be wringing our hands over how to continue to grow the economy in the face of a shrinking global population.
What I wrote is technically true (it's not a legally binding part of the "highest law", i.e. the Constittuion), and that was my main point, but I didn't actually know it was an act of the US Congress.
I know it was adopted by the pre-1787 "United States in Congress Assembled", but if it's in the US Code, then presumably it was also adopted by the post-1787 Congress, i.e. the one constituted by the Constitution.
> last time I read the document, it began with "WE HOLD THESE TRUTHS TO BE SELF-EVIDENT". *Self-evident*...
Read it again. That line is not in the US constitution, it's in the declaration of independence. The sentiment definitely informs all of the founding documents, but it's far from a legally-binding portion of the highest law of the US.