My friend had a Gateway XP tablet PC. Not bad for browsing the web but not that great for much else unless you hooked a keyboard and mouse to it. It was single touch and if you used your fingers to try and press the tiny maximize button on a window, you may accidentally close it. So the sylus was a must, if you didn't loose it.
If it had multitouch, pinch zoom, and gestures to manipulate windows then it might have been better. Its on screen keyboard was also a disaster and typing URL's was painful. But I will chalk that up as a crappy design decision.
"In 1984 Vilfredo, Heloisa and their children left their home, their work and school and set off from FlorianÃpolis, the capital city of the State of Santa Catarina, in southern Brazil, to pursue their dream: circumnavigate the world on a sailboat."
You need land for that to happen. I live around the corner from a large public school in New York City. The land was almost a split between the footprint of the building and the school yard itself. As the cities population grew, there was a shortage of classrooms. The solution was to extend the school and take away half of the school yard. So now the school yard is smaller. They also did this for another public grade school not too far from me as well. I know of one school that had what little of a school yard they had left filled in with an extension. Land plots of land are scarce or prohibitively expensive in cities.
There were also three new schools built near me, a high school and two grade schools. All on land that was purchased for what I can only assume was a lot of money. The high school was built on the site of an old multistory factory building. One grade school was squeezed into a lot was between a bowling alley and railroad tracks. The other was again between some buildings and next to some abandoned LIRR tracks.
My old Catholic grade school could no longer sustain itself as the neighborhood demographic changed. The school was sold off last year, demolished and a public school is taking its place.
The city is still short on classrooms. They setup a few of those trailer classrooms on the front lawn of the local high school and they do look ugly. And do students want to change classes on a rainy or cold snowy day?
I do a lot of industrial automation using steppers as they are very cheap and pretty robust for low speed work. In fact as we speak I am building a stepper indexer using off the self motors and drives.
Steppers stall because they are driven faster than the current can build up in the coils. As a result, the torque drops off since torque is directly proportional to the current in the motors coils. The motor can no longer move its load so it simply stalls. This happens after missing 2 or more steps and even if you remove the load the armature is stuck until the current is shut off. All of these 3D printers are probably using 12 volts to the bridge drivers which severely limits their torque curve.
One way to fix this is to increase the bus voltage to the bridge drivers. Industrial stepper drives mostly use 80-160V. Larger drives usually rectify the mains 120/240V AC and send it to the bridge drivers after some filtering. This allows the current to build faster and extend the torque curve further into the higher RPM's. But these are still stepper motors and they typically all drop torque after you go over 1000-2000 RPM. Remember, missed steps from resistance on the motor shaft is bad, it almost always leads to a stall.
Stepper motors are an indexing type motor and have physical teeth cut into the armature which line up with the stator poles. You index the motor by turning the poles on and off in sequence and the armature follows, cogging into place as the magnetic field lines up. Most steppers have 200 steps per rev, smaller steppers can vary quite a bit. There are a few stepper out there with more than 200, the 5 phase steppers from oriental motor are an example with 1000 steps per rev. The step count per rev can be increased using what is called micro stepping. The steps get divided up by varying current to the poles to hold the armature between the two poles using fast PWM.
Very rarely are steppers closed loop. If you command a stepper to move 200 counts, you will get 200 counts. The only reason you would need it is if you want to detect a few missed steps and compensate for it in your motion loop or detect a stall. The controller cant fix a stall unless it stops the current flows and starts over. And at that point you just ruined a part so its not much help.
Servo motors on the other hand can run at very high speeds. Servo drives can supply extra current when necessary to overcome resistance and keep the motion smooth and on track. This is done via the velocity loop which calculates the speed from the encoder feedback. When the motor slows, current is bumped up to overcome the resistance. But its usually only for a fraction of a second. Too much resistance and the drives will stop with an over current fault. You need to slow your system down, reduce the load or up the motor size.
Servo motors don't stall unless you lock up the output shaft which is usually a mechanical fault (hard limits hit, shaft coupler failure, bearing failure, etc.) or an undersized motor. And if you really want performance you get rid of the lead screws and rotary motors and go balls out with linear motors. They can achieve accuracies greater than 1 micron and speeds to 2+ meters per second. I have seen a few systems using them in person and its scary how fast they can gracefully accelerate and position a load.
And torque? Man they have torque. I had a large XY table with little NEMA 23 500W motors snap the aluminum couplings like a twig. The drive went bad, lost sync and tried to launch the table to the moon. Even jammed the table guides and ball screw nut requiring me to un-stick it with a come-along. A real mess. A similar sized stepper would have stalled. That table can easily position 500+ pounds though most of our motion is low speed so we don't need huge motors.
I would like to point out that meter placement is quite random in America. I own two commercial buildings and both buildings have their water, electric and gas meters inside. My home has its gas and water meters inside but the electric meter is on the outside. A family friend has his electric meter inside his home as well as his water and gas. Some new "brick shit box" multifamily homes that were hastily erected to cash in on the housing bubble have both the electric and gas meters right out in the open. Often right in the front of the house next to the entrance. My brother lived in an apartment where the gas meter was actually inside one of his overhead kitchen cabinets and was only for the stove. The electric and water meters are probably in the basement.
The only meter that you will never find outside in a region that has cold winters is the water meter as they will freeze and burst in the winter. I imagine in some warm parts of the US (that never see freezing) could have their water meters outside.
Also, most meters are electronic and do not require entrance to your property.
Also you can't send out a signal along a pipe that is exposed to earth. Its like burying an antenna and then wondering why you cant get a reception. They also now use plastic pipes for gas mains.
I was assuming $1000 per year as the GP did not post any information. And while $1000/yr sounds crazy, a yearly fee to drive an EV on public roads does make sense. How else do they charge you for using the roads? And before you say log miles via odometer checks or GPS, think of the privacy concerns and fraud opportunities that come with it. I would say make it a flat rate depending on the vehicles class or weight.
If the vehicles are autonomous EV's, they will loose even more money. If they are loosing money from fuel taxes and traffic violation the next line of budget defense is the DMV. Think about it, your registration fees can be used as a method to reclaim lost revenue. It could be a yearly, monthly or quarterly charge and if you fail to pay, your cars registration is suspended. That right there could lead to more fines and fees so the cycle of plundering continues. They move to a direct method for funding the roads.
This system might also get more people off the roads and on to bikes, buses, trains and taxis. If a person does not drive much per year yet has to pay a fixed road use rate, it might not be worth it for them and they will forgo owning a car.
$1000 sounds more like a punishment for buying an EV. Can you post a link to the proposal?
The average driver travels about 15,000 miles (~24.000km) each year in the US. Even if it were a gas hungry van or SUV getting 12 MPG you are looking at only $618 in fuel tax for 15,000 miles using the national average* of 49.5 cents/gallon. You would need to buy about 2000 gallons of gasoline (using the national average) before you hit $1000. With a fuel efficient car getting at least 30MPG combined you will only pay $~247 if you drove 15,000 miles each year.
I am not familiar with the EV/MPG stuff but I look at it in terms of battery capacity and miles per charge. I used the leaf as an example.
The Leafs battery pack is 24kWh and has a range of 75 miles. So that right there is a rough estimate of 24kWh consumed from your homes electric system per 75 miles driven. It probably more depending on driving conditions, weather and efficiency but lets ignore that. to drive 15,000 miles you need (15,000/75)*24 = 4800kW hours of electricity. The national average* cost per kWh is about 12 cents. That works out to $576 per year in electric for 15,000 miles. Not bad.
Now lets compare that to a vehicle getting 30 MPG combined and driving 15,000 miles using the national average fuel price of $3.53. That will cost an estimated $1765 per year.
An EV fee of $1000 will raise your yearly operating cost to $~1600 (not including insurance and air freshener costs). At that price the advantage of owning a an EV and its lower energy cost almost goes out the window. I'd imagine a more efficient diesel car would break even with the electric car.
So an autonomous EV will will really put a dent in their pockets unless they cut the fat or just charge more money to register each year.
"oh? what problem does it solve?" What the fuck is so hard to understand here? The answer is in the name of project: An opensource CPU core. There, was that so hard?
Besides being a snarky ass, what was the point of your post? It sounds as if you would rather spark a flame war rather than do some actual research which would take oh lets say 5-10 minutes.
There are other open source cores but none of them are trying to provide a full blown CPU core that could potentially be used for mobile or desktop use. Most of them are for embedded use and are little more than a micro controller and lack an MMU.
The low latency of memory mapped interfaces such as PCI, Firewire and now Thunderbolt make them excellent buses for hard real time systems which need timing down in the micro or nano second range. I work with a motion control system that uses fire wire to connect smart servo drives to a Windows host running a real time kernel (Ardence RTX). It can maintain >10us latency between the drives on an 8000MHz Pentium 3 and Windows still has plenty of CPU time left. You can't do that with USB.
Another disadvantage of USB is that devices cant send interrupts and have no DMA capabilities (a security advantage). The host has to poll each device which is costly in both time and CPU cycles. Firewire devices copy data to memory without the CPU using DMA thus avoiding interrupts. Thunderbolt and PCIe can both take advantage of DMA and message signaled interrupts.
"I would actually appreciate it if you used them more and got into a car with someone who did you much harm, resolving two issues at once."
I'm not one to waste time on trollish assholes like you but seriously, you need to take some medication or at least get some therapy. Here you are telling this person to die in a car accident. Seriously? You think its healthy and normal to rant like this? Go get some help for your anger issues. I have never encountered someone this site that spews so much anger and hate at others.
And shame on the person who modded this "Insightful".
I would guess that many of the e-books on the reader are rules, manuals and procedures for current military hardware and practices which are unlikely to change in the next few years. The military does not like change for the sake of simplicity and reliability. I imagine the e-reader with its fixed documents will fit right in.
I am by no means a submersible expert and I am curious as to what part of the sub imploded.
16,000 PSI might sound like a lot of pressure but in reality we use pressures close to that in hydraulic systems (10,000 PSI systems are quite common) and well over that in hydro-forming systems.
Would vacuuming and back filling the air spaces with a non conductive fluid such as Fluorinert or mineral oil be of any benefit? If you eliminate compressible gases from the design, nothing can implode. Weight could be an issue but the liquid can also help ballast the vehicle. The only spot that could be a problem is with motors but the stator coils could be sealed in a fluid or potted cavity and the armature/rotor could live outside under the external pressure and simply use magnetic coupling (like they do in fish tank filters). Maintenance would be a PITA but sounds like a worthy sacrifice to get something to safely handle those pressures.
A train uses air pressure to actuate the brakes but uses inverse logic to apply them. The basic principal is as the system charges via the compressor, the brakes begin to apply. Once the system reaches full pressure, the brakes release and are operated by dropping the pressure in the brake line in a controlled fashion using a valve. The problem is either way, you need air pressure for the system to work. The emergency fail safe function is when the brake line is suddenly exhausted, the train cars apply their brakes using *existing pressure* in their tanks. If the tanks loose air pressure (from leaks) the brakes will again release allowing the cars to roll.
So how do they keep cars "parked" without needing an air compressor? They apply the hand brakes (which you might have seen in a film or cartoon) by turning a large hand wheel which mechanically locks the brakes. They are 100% manual and train crew personnel need to go from car to car to apply or release them.
From reading the article on the Lac-Megantic derailment, it looks like the operator was poorly trained and proper safety protocol as well as common sense was outright ignored. The operator did not apply any hand brakes and knowingly left a malfunctioning locomotive unattended for a long period of time. Talk about a glaring mistake. I can see this as a problem stemming from the reduction of train crews to one guy who has to manually locks dozens of cars taking 2-3 minutes each car.
On a side note: Air brake systems for trucks are dual system with two circuits for redundancy. The first system is the spring brake system which is a fail safe emergency/parking brake. To release it you need at least 60 PSI (4.13 BAR) before the knob on the dash will release the brakes. If for any reason you loose air pressure, the knob pops out and springs apply the brakes (and alarms sound). The spring brakes are mechanical and are released using air pressure. This is what makes them fail safe. The second system is the service brake system. This is the brake system that slows/stops the truck during normal operation. It does not work like a train and you need pressure to apply the brakes supplied from the foot valve (brake pedal). But there are two service circuits, one for the driving rear axles (primary) and one for the steering and sometimes lift or auxiliary axles (secondary). Both circuits feed the trailer lines and the spring brake system. If one system fails, the other system is isolated via check valves and can maintain controlled braking. They are both fed from a single compressor and air accessories such as suspensions and horns are fed from yet another tank that does not affect pressure in the service circuits (though this varies in later models). The trailer(s) has its own independent spring/service system and is automatically isolated from the tractor in emergency situations via the tractor protection valve. This also applies the trailers spring brakes. Even if a truck is left for a long period of time and looses all of its air pressure, the mechanical springs will hold the brakes indefinitely (unless of course, the brakes are poorly maintained). Its a shame trains have not caught up in this regard.
We learned from Hurricane Sandy that salt water on land isn't an environmental disaster in terms of its impact on vegetation. Most areas flooded experienced little effect on local vegetation and I should know, I live in south Queens (not effected by Sandy though, I am north of the Belt Parkway.) A few plants and trees died but that was about it. Everyone still has green lawns and plenty of trees. The bigger issue was with oil and and fuel getting washed out of cars and into the ground along with mold concerns.
"As I was googling around one of the staff at adobe mentioned last year that Linux lacked standardized APIs on a forum thread regarding photoshop on Linux."
And that is a reliable source of information? Most likely Adobe devs don't want to support yet another GUI toolkit/API. Linux has different GUI tool kits available, the most common being QT and GTK, both of which support Windows and MacOS in addition to the usual open source suspects. Hell, if you write a GUI Linux app that uses a cross platform tool kit and don't rely on X libs, you can in theory recompile them against Wayland or Mir without any changes.
There are plenty of standards in Linux as far as API's are concerned. The only real problem (which is not a bug but a feature, I'll explain below) is binary compatibility across distros as there are different library versions shipped with different releases and paths to said libraries can vary slightly. Package management (rpm, apt, etc) also varies from distro to distro. This is why you don't see universal binaries which can be a hassle for developers of proprietary software. OSX uses universal binaries which sort of solves this problem. Universal binaries were proposed back in 2009 for Linux but the patches were rejected by the LKML crowd.
Just look at the OpenSSL heartbleed fiasco as a great example for that reasoning. They had all sorts of legacy code and custom memory handling to support obsolete systems such as Windows 3.1x and pre MacOS X (8/9). Sure they were an open source project but they fell into the backwards compatibility trap. This is the same reason Windows became a security mess. Many of its libraries and API's have backwards compatibility with software from nearly 20 years ago (Windows 95). But it is what also makes it a convenient development platform. You could in theory release a binary in 2000 and it should still work in 2014. You can write Windows code using strait C by calling the win32 API's and you can build that code for 95/98/NT/Me/2k/XP/7/8. There is also backward compatibility for older.net, c++ libs, DirectX, etc. This is perfect for users of older software who: don't need to upgrade, can't afford to upgrade, need to support older systems or the developer is out of business and the user depend on that software. Same goes for games. In many cases older windows games run just fine. Though Windows does not support 100% backwards compatibility, it certainly has a lot of it.
Whereas in open source land, backwards compatibility is not expected between versions. With Linux and open source in general, if a library is changed and a feature deprecated or removed, you tweak your source and rebuild. Though not everyone wants to or can for that matter, build or tweak source. So distros provide binary packages of common software and libraries for the sake of being user friendly. But that hampers closed source developers who want to protect their IP. I don't blame them but they have to adjust to the ever evolving world of open source libraries and API's. This is the same reason video card drivers on Linux are a huge headache. Instead of providing binary drivers they have to provide a whole obfuscated build environment to pull in the necessary libs and kernel headers for your distro and compile the driver against them. If the video card developers released the source, distros could provide drivers downstream tailored for their distro.
Its a totally different eco system for the game devs and they have to adjust. But its not a huge uphill battle. Crytek ported the Cryengine to Linux and Unreal 4, which is becoming a very easy to use game engine on par with Unity, runs on Linux. So we have major engines now available for Linux and I can't help but think this is all thanks to Valve. Thanks Valve!
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My friend had a Gateway XP tablet PC. Not bad for browsing the web but not that great for much else unless you hooked a keyboard and mouse to it. It was single touch and if you used your fingers to try and press the tiny maximize button on a window, you may accidentally close it. So the sylus was a must, if you didn't loose it.
If it had multitouch, pinch zoom, and gestures to manipulate windows then it might have been better. Its on screen keyboard was also a disaster and typing URL's was painful. But I will chalk that up as a crappy design decision.
"In 1984 Vilfredo, Heloisa and their children left their home, their work and school and set off from FlorianÃpolis, the capital city of the State of Santa Catarina, in southern Brazil, to pursue their dream: circumnavigate the world on a sailboat."
Sounds like the Schurmanns had plenty of money.
You need land for that to happen. I live around the corner from a large public school in New York City. The land was almost a split between the footprint of the building and the school yard itself. As the cities population grew, there was a shortage of classrooms. The solution was to extend the school and take away half of the school yard. So now the school yard is smaller. They also did this for another public grade school not too far from me as well. I know of one school that had what little of a school yard they had left filled in with an extension. Land plots of land are scarce or prohibitively expensive in cities.
There were also three new schools built near me, a high school and two grade schools. All on land that was purchased for what I can only assume was a lot of money. The high school was built on the site of an old multistory factory building. One grade school was squeezed into a lot was between a bowling alley and railroad tracks. The other was again between some buildings and next to some abandoned LIRR tracks.
My old Catholic grade school could no longer sustain itself as the neighborhood demographic changed. The school was sold off last year, demolished and a public school is taking its place.
The city is still short on classrooms. They setup a few of those trailer classrooms on the front lawn of the local high school and they do look ugly. And do students want to change classes on a rainy or cold snowy day?
It not as easy or cheap as we all want it to be.
You forgot to add "a long time ago..."
I do a lot of industrial automation using steppers as they are very cheap and pretty robust for low speed work. In fact as we speak I am building a stepper indexer using off the self motors and drives.
Steppers stall because they are driven faster than the current can build up in the coils. As a result, the torque drops off since torque is directly proportional to the current in the motors coils. The motor can no longer move its load so it simply stalls. This happens after missing 2 or more steps and even if you remove the load the armature is stuck until the current is shut off. All of these 3D printers are probably using 12 volts to the bridge drivers which severely limits their torque curve.
One way to fix this is to increase the bus voltage to the bridge drivers. Industrial stepper drives mostly use 80-160V. Larger drives usually rectify the mains 120/240V AC and send it to the bridge drivers after some filtering. This allows the current to build faster and extend the torque curve further into the higher RPM's. But these are still stepper motors and they typically all drop torque after you go over 1000-2000 RPM. Remember, missed steps from resistance on the motor shaft is bad, it almost always leads to a stall.
Stepper motors are an indexing type motor and have physical teeth cut into the armature which line up with the stator poles. You index the motor by turning the poles on and off in sequence and the armature follows, cogging into place as the magnetic field lines up. Most steppers have 200 steps per rev, smaller steppers can vary quite a bit. There are a few stepper out there with more than 200, the 5 phase steppers from oriental motor are an example with 1000 steps per rev. The step count per rev can be increased using what is called micro stepping. The steps get divided up by varying current to the poles to hold the armature between the two poles using fast PWM.
Very rarely are steppers closed loop. If you command a stepper to move 200 counts, you will get 200 counts. The only reason you would need it is if you want to detect a few missed steps and compensate for it in your motion loop or detect a stall. The controller cant fix a stall unless it stops the current flows and starts over. And at that point you just ruined a part so its not much help.
Servo motors on the other hand can run at very high speeds. Servo drives can supply extra current when necessary to overcome resistance and keep the motion smooth and on track. This is done via the velocity loop which calculates the speed from the encoder feedback. When the motor slows, current is bumped up to overcome the resistance. But its usually only for a fraction of a second. Too much resistance and the drives will stop with an over current fault. You need to slow your system down, reduce the load or up the motor size.
Servo motors don't stall unless you lock up the output shaft which is usually a mechanical fault (hard limits hit, shaft coupler failure, bearing failure, etc.) or an undersized motor. And if you really want performance you get rid of the lead screws and rotary motors and go balls out with linear motors. They can achieve accuracies greater than 1 micron and speeds to 2+ meters per second. I have seen a few systems using them in person and its scary how fast they can gracefully accelerate and position a load.
And torque? Man they have torque. I had a large XY table with little NEMA 23 500W motors snap the aluminum couplings like a twig. The drive went bad, lost sync and tried to launch the table to the moon. Even jammed the table guides and ball screw nut requiring me to un-stick it with a come-along. A real mess. A similar sized stepper would have stalled. That table can easily position 500+ pounds though most of our motion is low speed so we don't need huge motors.
Ah, so about half a football field. Thanks!
I would like to point out that meter placement is quite random in America. I own two commercial buildings and both buildings have their water, electric and gas meters inside. My home has its gas and water meters inside but the electric meter is on the outside. A family friend has his electric meter inside his home as well as his water and gas. Some new "brick shit box" multifamily homes that were hastily erected to cash in on the housing bubble have both the electric and gas meters right out in the open. Often right in the front of the house next to the entrance. My brother lived in an apartment where the gas meter was actually inside one of his overhead kitchen cabinets and was only for the stove. The electric and water meters are probably in the basement.
The only meter that you will never find outside in a region that has cold winters is the water meter as they will freeze and burst in the winter. I imagine in some warm parts of the US (that never see freezing) could have their water meters outside.
Also, most meters are electronic and do not require entrance to your property.
Also you can't send out a signal along a pipe that is exposed to earth. Its like burying an antenna and then wondering why you cant get a reception. They also now use plastic pipes for gas mains.
I was assuming $1000 per year as the GP did not post any information. And while $1000/yr sounds crazy, a yearly fee to drive an EV on public roads does make sense. How else do they charge you for using the roads? And before you say log miles via odometer checks or GPS, think of the privacy concerns and fraud opportunities that come with it. I would say make it a flat rate depending on the vehicles class or weight.
If the vehicles are autonomous EV's, they will loose even more money. If they are loosing money from fuel taxes and traffic violation the next line of budget defense is the DMV. Think about it, your registration fees can be used as a method to reclaim lost revenue. It could be a yearly, monthly or quarterly charge and if you fail to pay, your cars registration is suspended. That right there could lead to more fines and fees so the cycle of plundering continues. They move to a direct method for funding the roads.
This system might also get more people off the roads and on to bikes, buses, trains and taxis. If a person does not drive much per year yet has to pay a fixed road use rate, it might not be worth it for them and they will forgo owning a car.
Negative. K-9 would be a better example.
The Cybermen have living human brains. They are cyborgs, not robots.
$1000 sounds more like a punishment for buying an EV. Can you post a link to the proposal?
The average driver travels about 15,000 miles (~24.000km) each year in the US. Even if it were a gas hungry van or SUV getting 12 MPG you are looking at only $618 in fuel tax for 15,000 miles using the national average* of 49.5 cents/gallon. You would need to buy about 2000 gallons of gasoline (using the national average) before you hit $1000. With a fuel efficient car getting at least 30MPG combined you will only pay $~247 if you drove 15,000 miles each year.
I am not familiar with the EV/MPG stuff but I look at it in terms of battery capacity and miles per charge. I used the leaf as an example.
The Leafs battery pack is 24kWh and has a range of 75 miles. So that right there is a rough estimate of 24kWh consumed from your homes electric system per 75 miles driven. It probably more depending on driving conditions, weather and efficiency but lets ignore that. to drive 15,000 miles you need (15,000/75)*24 = 4800kW hours of electricity. The national average* cost per kWh is about 12 cents. That works out to $576 per year in electric for 15,000 miles. Not bad.
Now lets compare that to a vehicle getting 30 MPG combined and driving 15,000 miles using the national average fuel price of $3.53. That will cost an estimated $1765 per year.
An EV fee of $1000 will raise your yearly operating cost to $~1600 (not including insurance and air freshener costs). At that price the advantage of owning a an EV and its lower energy cost almost goes out the window. I'd imagine a more efficient diesel car would break even with the electric car.
So an autonomous EV will will really put a dent in their pockets unless they cut the fat or just charge more money to register each year.
And yet we have multiple open source web servers, each with varying levels of complexity, feature sets and usage cases.
Com on, this is N. Korea we are talking about. They are nothing more than spray painted horses with a fake horn screwed to their skulls.
Its free but you have to pay for the construction cost of installation. Last I saw it was $300 but I think it has been reduced to $30 in some areas.
"oh? what problem does it solve?"
What the fuck is so hard to understand here? The answer is in the name of project: An opensource CPU core. There, was that so hard?
Besides being a snarky ass, what was the point of your post? It sounds as if you would rather spark a flame war rather than do some actual research which would take oh lets say 5-10 minutes.
There are other open source cores but none of them are trying to provide a full blown CPU core that could potentially be used for mobile or desktop use. Most of them are for embedded use and are little more than a micro controller and lack an MMU.
This security hole can be easily plugged via the use of the IOMMU: http://en.wikipedia.org/wiki/DMA_attack#Mitigations
The low latency of memory mapped interfaces such as PCI, Firewire and now Thunderbolt make them excellent buses for hard real time systems which need timing down in the micro or nano second range. I work with a motion control system that uses fire wire to connect smart servo drives to a Windows host running a real time kernel (Ardence RTX). It can maintain >10us latency between the drives on an 8000MHz Pentium 3 and Windows still has plenty of CPU time left. You can't do that with USB.
Another disadvantage of USB is that devices cant send interrupts and have no DMA capabilities (a security advantage). The host has to poll each device which is costly in both time and CPU cycles. Firewire devices copy data to memory without the CPU using DMA thus avoiding interrupts. Thunderbolt and PCIe can both take advantage of DMA and message signaled interrupts.
" This is just another cause-we-can hobby project on the front page of Slashdot."
OpenRISC is far from a "cause-we-can" project.
Problem with that is if you soil your mattress and flip it, you now have to launder dirty money.
"I would actually appreciate it if you used them more and got into a car with someone who did you much harm, resolving two issues at once."
I'm not one to waste time on trollish assholes like you but seriously, you need to take some medication or at least get some therapy. Here you are telling this person to die in a car accident. Seriously? You think its healthy and normal to rant like this? Go get some help for your anger issues. I have never encountered someone this site that spews so much anger and hate at others.
And shame on the person who modded this "Insightful".
I would guess that many of the e-books on the reader are rules, manuals and procedures for current military hardware and practices which are unlikely to change in the next few years. The military does not like change for the sake of simplicity and reliability. I imagine the e-reader with its fixed documents will fit right in.
I think the gooey maple syrup finger prints on the hardware would give them away....
I am by no means a submersible expert and I am curious as to what part of the sub imploded.
16,000 PSI might sound like a lot of pressure but in reality we use pressures close to that in hydraulic systems (10,000 PSI systems are quite common) and well over that in hydro-forming systems.
Would vacuuming and back filling the air spaces with a non conductive fluid such as Fluorinert or mineral oil be of any benefit? If you eliminate compressible gases from the design, nothing can implode. Weight could be an issue but the liquid can also help ballast the vehicle. The only spot that could be a problem is with motors but the stator coils could be sealed in a fluid or potted cavity and the armature/rotor could live outside under the external pressure and simply use magnetic coupling (like they do in fish tank filters). Maintenance would be a PITA but sounds like a worthy sacrifice to get something to safely handle those pressures.
Yup. I was wrong. Somehow I missed that part.
This is a good question which I just did a bit of research on. I have a good understanding of a trucks air brake system and though different from a trains, have similar principals. Se this article: http://en.wikipedia.org/wiki/Railway_air_brake#Westinghouse_air_brake
A train uses air pressure to actuate the brakes but uses inverse logic to apply them. The basic principal is as the system charges via the compressor, the brakes begin to apply. Once the system reaches full pressure, the brakes release and are operated by dropping the pressure in the brake line in a controlled fashion using a valve. The problem is either way, you need air pressure for the system to work. The emergency fail safe function is when the brake line is suddenly exhausted, the train cars apply their brakes using *existing pressure* in their tanks. If the tanks loose air pressure (from leaks) the brakes will again release allowing the cars to roll.
So how do they keep cars "parked" without needing an air compressor? They apply the hand brakes (which you might have seen in a film or cartoon) by turning a large hand wheel which mechanically locks the brakes. They are 100% manual and train crew personnel need to go from car to car to apply or release them.
From reading the article on the Lac-Megantic derailment, it looks like the operator was poorly trained and proper safety protocol as well as common sense was outright ignored. The operator did not apply any hand brakes and knowingly left a malfunctioning locomotive unattended for a long period of time. Talk about a glaring mistake. I can see this as a problem stemming from the reduction of train crews to one guy who has to manually locks dozens of cars taking 2-3 minutes each car.
On a side note: Air brake systems for trucks are dual system with two circuits for redundancy. The first system is the spring brake system which is a fail safe emergency/parking brake. To release it you need at least 60 PSI (4.13 BAR) before the knob on the dash will release the brakes. If for any reason you loose air pressure, the knob pops out and springs apply the brakes (and alarms sound). The spring brakes are mechanical and are released using air pressure. This is what makes them fail safe. The second system is the service brake system. This is the brake system that slows/stops the truck during normal operation. It does not work like a train and you need pressure to apply the brakes supplied from the foot valve (brake pedal). But there are two service circuits, one for the driving rear axles (primary) and one for the steering and sometimes lift or auxiliary axles (secondary). Both circuits feed the trailer lines and the spring brake system. If one system fails, the other system is isolated via check valves and can maintain controlled braking. They are both fed from a single compressor and air accessories such as suspensions and horns are fed from yet another tank that does not affect pressure in the service circuits (though this varies in later models). The trailer(s) has its own independent spring/service system and is automatically isolated from the tractor in emergency situations via the tractor protection valve. This also applies the trailers spring brakes. Even if a truck is left for a long period of time and looses all of its air pressure, the mechanical springs will hold the brakes indefinitely (unless of course, the brakes are poorly maintained). Its a shame trains have not caught up in this regard.
We learned from Hurricane Sandy that salt water on land isn't an environmental disaster in terms of its impact on vegetation. Most areas flooded experienced little effect on local vegetation and I should know, I live in south Queens (not effected by Sandy though, I am north of the Belt Parkway.) A few plants and trees died but that was about it. Everyone still has green lawns and plenty of trees. The bigger issue was with oil and and fuel getting washed out of cars and into the ground along with mold concerns.
"As I was googling around one of the staff at adobe mentioned last year that Linux lacked standardized APIs on a forum thread regarding photoshop on Linux."
And that is a reliable source of information? Most likely Adobe devs don't want to support yet another GUI toolkit/API. Linux has different GUI tool kits available, the most common being QT and GTK, both of which support Windows and MacOS in addition to the usual open source suspects. Hell, if you write a GUI Linux app that uses a cross platform tool kit and don't rely on X libs, you can in theory recompile them against Wayland or Mir without any changes.
There are plenty of standards in Linux as far as API's are concerned. The only real problem (which is not a bug but a feature, I'll explain below) is binary compatibility across distros as there are different library versions shipped with different releases and paths to said libraries can vary slightly. Package management (rpm, apt, etc) also varies from distro to distro. This is why you don't see universal binaries which can be a hassle for developers of proprietary software. OSX uses universal binaries which sort of solves this problem. Universal binaries were proposed back in 2009 for Linux but the patches were rejected by the LKML crowd.
Just look at the OpenSSL heartbleed fiasco as a great example for that reasoning. They had all sorts of legacy code and custom memory handling to support obsolete systems such as Windows 3.1x and pre MacOS X (8/9). Sure they were an open source project but they fell into the backwards compatibility trap. This is the same reason Windows became a security mess. Many of its libraries and API's have backwards compatibility with software from nearly 20 years ago (Windows 95). But it is what also makes it a convenient development platform. You could in theory release a binary in 2000 and it should still work in 2014. You can write Windows code using strait C by calling the win32 API's and you can build that code for 95/98/NT/Me/2k/XP/7/8. There is also backward compatibility for older .net, c++ libs, DirectX, etc. This is perfect for users of older software who: don't need to upgrade, can't afford to upgrade, need to support older systems or the developer is out of business and the user depend on that software. Same goes for games. In many cases older windows games run just fine. Though Windows does not support 100% backwards compatibility, it certainly has a lot of it.
Whereas in open source land, backwards compatibility is not expected between versions. With Linux and open source in general, if a library is changed and a feature deprecated or removed, you tweak your source and rebuild. Though not everyone wants to or can for that matter, build or tweak source. So distros provide binary packages of common software and libraries for the sake of being user friendly. But that hampers closed source developers who want to protect their IP. I don't blame them but they have to adjust to the ever evolving world of open source libraries and API's. This is the same reason video card drivers on Linux are a huge headache. Instead of providing binary drivers they have to provide a whole obfuscated build environment to pull in the necessary libs and kernel headers for your distro and compile the driver against them. If the video card developers released the source, distros could provide drivers downstream tailored for their distro.
Its a totally different eco system for the game devs and they have to adjust. But its not a huge uphill battle. Crytek ported the Cryengine to Linux and Unreal 4, which is becoming a very easy to use game engine on par with Unity, runs on Linux. So we have major engines now available for Linux and I can't help but think this is all thanks to Valve. Thanks Valve!