I currently only use the PC version but as far as I know you can SSH into any of the pfsense variations assuming you enable it and have the appropriate firewall rule allowing access. The console only quote for the embedded version probably refers to a lack of display and keyboard support.
You are not getting more energy out then you put in because it has to do with moving heat from one area to another when the temperature difference betweenthe two is relatively low allowing higher efficiency then a straight heater. I probably should have said that the coefficient of performance can be in the 3 to 5 range making it very competetive with gas heating systems. The COP of an electric heater is always 1.
In the case of computer power supplies that use a rectifier and capacitor combination for AC to DC conversion which is almost all of them, they do not look like an inductive or capacitive load but have a lower power factor caused by drawing current in pulses instead of a sine wave. The result is a higher RMS current then necessary for the load which causes increased line losses and requires higher current capacity for a given power. In extreme cases, distribution transformers can go into saturation causing additional losses.
A power factor of 0.6 does not mean 0.6 watts available for every watt sent. It means the capacity of the line is reduced to 60% of normal do to excessive circulating current. This is easy to see when you look at the rated output power of a typical wall socket, 120 VAC x 15 A = 1800 W, of which you can only use 1100 watts (actually 1080) for a computer load. 1100 watts is the largest common size for inexpensive uninterruptible power supplies for this very reason.
A 0.6 power factor should cause about a 66% increase in line losses for a given load.
Heat pumps can be effectively more then 100% efficient when heating a home however their efficiency goes down as the outside temperature gets colder. Typical numbers are 3 to 5 watt of heat for every watt of power in temperate climates.
Electrically these antennas are still 1/4 wave long through the use of a loading coil at the base which has a detrimental effect on performance. Designing one into a laptop case with acceptable performance do to near field effects would be quite a challenge and entail a lot of compromise.
At the lower end of the VHF band even if the relatively large antenna size approaching 1.5 meters for 1/4 wave was not a problem the useable bandwidth of the antenna would preclude efficient wide frequency operation. The low end of the UHF spectrum above 440 MHz on the other hand would work very well.
By stipulating this, Stallman is implicitly calling for civil disobedience, at least where US law is concerned. Whether you consider that *morally* appropriate in itself is another issue...but what he is effectively saying is that the legal requirements of the GPL v3 are in direct conflict with American law. I am assuming there that the law is one prohibiting reverse engineering of software.
I agree RMS is pushing very hard on the issue of DRM and the DMCA subverting the intent of the GPL but how does the GPL v3 in this case conflict with US law? It seems more like a conflict between copyright and the DMCA. Some manufacturers want to use GPL licensed source code in their products and then use some combination of DRM and the DMCA to effectively defeat one of the purposes of the GPL. If the manufacturer does not agree to the license then it just becomes a copyright issue and they can not legally use the source code in their product. Either they can provide the necessary public key to allow interoperability or they can allow reverse engineering of the hardware. If they wish to keep the system closed then just do not use GPL v3 and similarly licensed software.
I would have to check to be sure but I don't recall the puppeteers being responsible for the fall of the cities. Wasn't it an unspecified ramscoop freighter which was assumed to have brought the infection from an old colony world?
How fortuitous that I am currently rereading the Ringworld books although I would have remembered this even without doing so. In the first book it is speculated that a City Builder ship carried the superconductor plague from one of their abandoned worlds. In the second book, Louis becomes suspicious after being told by the Hindmost that the plague will not affect the superconductor wire or cloth that he brought. How could the Hindmost know? Later it is reveled that the Puppeteer experimentalist faction had deliberately created the plague and seeded the Ringworld with it about 1000 years earlier. No definitive reason for this action is given but speculation in the books is that the Puppeteers may have been looking into the possibility of colonization. The original expedition (Ringworld) was sent to discover how the structure had survived the fall of the civilization that kept it in repair. The second expedition (Ringworld Engineers) goes so that the deposed Hindmost can recover his position by stealing technology.
From The Ringworld Throne:
1733 AD - Puppeteer Experimentalist regime introduces superconductor plague to Ringworld
- Fall of the Cities 2851 AD - Ringworld
- Lying Bastard shot down and impacts Ringworld 2878 AD - Ringworld Engineers
- Hot Needle of Inquiry reaches Ringworld
Do you mean to say that viruses could be introduced into an organism to change DNA? If so would it be possible for there to be something like inheritance where genetic characteristics propogate directly between organisms rather than through reproduction?
I am not entirely clear what you are asking but there are cases where children express phenotypes controlled by the mother's DNA. In some species of snail, the direction of the child's shell rotation is controlled by the mother's genes.
This is an aspect of perceived recoil which depends not only on bullet velocity, mass, and powder charge but also on how the recoil system operates to distribute the energy over time. Excluding the semiautomatic Webley-Fosbery, revolver barrels are fixed to their frame and tend to have a high center of recoil leading to their sharp upwards movement. When I shoot my old Herter.357 with even less then maximum loads, the slap in my palm and the web of my thumb actually stings. My Thompson Center Contender single shot pistol in.44 magnum or in a medium rifle load is much more pleasant to shoot because of its larger mass, larger rear grip surface area, and lower center of recoil although one needs to be prepared as I discovered when one of my friends tried it and ended up scratching his glasses with the hammer spur. Safely using high power pistols really requires practice in the same way that one would learn any physical skill.
For semiautomatic pistols blowback is much sharper then short recoil. This does not matter for.22 long rifle but depending on the details, a.380 auto using blowback can be much more punishing then 9mm using short recoil despite 9mm being more powerful.
Isn't -48 still 48Volts of differential, so why not just +48V? I'm no EE, so I'm obviously missing something here.
The voltage is measured with respect to ground and in this case indicates that the positive side is grounded instead of the negative side which most people would be used to. Using a positive ground mitigates corrosion where you have wiring buried in the ground or potentially exposed to the weather.
If you want even more confusion, consider that electron current flow is negative to positive and for historical reasons the arrows used to indicate a PN junction point in the opposite direction.
It could have worked the other way as well. We know the aliens had visited earth earlier so maybe Microsoft licensed Windows to them. This also gives them a great motive for the attack. WGA also pissed me off when it screwed up my system.
P.S. I know Goldblum used a Mac. Why would I let that get in the way of a story about revenge on Microsoft?
I remember Ayn Rand stating in an interview that revolt would be appropriate for defense of the 1st Ammendment but was not able to find a reference and may be misremembering. I consider the following from Unintended Consequences by John Ross to be both more elequent then my own words and more appropriate:
A women is confronted by a big, strong, stranger. She does not know what he is planning, and she is cautious. Getting away from him is not possible. They are in a room and he is standing in front of the only way out, or she is in a wheelchair - whatever. Leaving the area is not an option.
So now he starts to do things she does not like. He asks her for money. She can try to talk him out of it, just like we argue for lower taxes, and maybe it will work. If it does not, and she gets outvoted, she will probably choose to give in to him instead of getting into a fight to the death over ten dollars. You would probably choose to pay your taxes rather then have police arrive to throw you in jail.
Maybe this big man demands some other things, other minor assaults on this woman's dignity. When should she claw at his eyes or shove her ballpoint pen in his throat? When he tries to force her to kiss him? Tries to force her to let him touch her? Tries to force her to have sex with him?
Those are questions that each woman has to answer for herself. There is one situation, though, where I tell the women to fight to the death. That is when the man pulls out a pair of handcuffs and says, "Come on, I promise I won't hurt you, this is just so you won't flail around and hurt either of us by accident. Come on, I just want to talk, get in the van and let me handcuff you to this eyebolt here, and I promise I won't touch you. I'm not asking you to put on a gag or anything, and since you can still scream for help, you know you'll be safe. Come on, I've got a full bar in here, and color TV, and air-conditioning, great stereo, come on, just put on the cuffs."
I tell women that if that ever happens, maybe the man is telling the truth, and maybe after talking to her for a while he will let her go and she will have had a good time drinking champagne and listening to music. But if she gets in the van and puts her wrists in the handcuffs, she has just given up her future ability to fight, and now it is too late.
How do you spot the precise point where a society is standing at the back of the van and the State has the handcuffs out?
- Henry Bowman, May 7, 1973 - Unintended Consequences, John Ross
In a design using semiconductors from about 1970 with little or no integration available for the digital filters required? Delta sigma converters are really good for taking advantage of inexpensive digital logic integration but are only the most recent in a long series of converter architectures.
Single and dual slope integrating as well as various voltage to frequency converter designs were available and with care could have met their requirements for environment and size. TI probably had military temperature range chip sets for them even then. Successive approximation designs would have probably been in multi-chip modules because of the requirement for resistive ratio matching and were popular for military applications but I am not sure when they first came out like that. None of these would have been even close to 20 bits but I think that specification was inaccurate and only reflected the CPU data width. I really enjoy reverse engineering old equipment like this just to understand the designer's mind set.
I found a couple of papers at http://www.microcomputerhistory.com/f14paper.htm with more CPU design details but nothing significant about the converters or signal conditioning. The more I think about it the more I suspect the 20 bit quote was just given because of the data word size and has nothing to do with the actual resolution or linearity which were probably 8 to 10 bits.
That is an interesting read. I wonder how the 20 bit converters were designed. They do not say but if they were used for what would be considered an instrumentation application and had 18 bits of linearity, I would assume some type of charge balancing scheme or single slope integrating. I doubt I could do better then 16 bits on the first shot with a discrete design.
The DMA 32 bit addressing limitations are mostly a function of the memory controller and various expansion devices including some poorly designed or tested PCI cards. Because of the K8's built in memory controller, AMD was in a position to ameliorate this problem to some extent through use of the GART as a limited IOMMU in a standardized way. Intel would have had to build this functionality into its north bridge memory controllers which would have made universal support very difficult never mind third party north bridge support.
Google "iommu AMD gart" or "iommu Intel gart" for more details.
I am somewhat fuzzy on the principle of operation but a very similar setup is used on laminar flow tables and is suppose to significantly reduce any ESD hazard. On the ones I have used, there is a bar at the back of the table within the airflow that has a multitude of insulated sharp charged emitters.
I remember visiting the Exploratorium in San Francisco many years ago (highly recommended) and playing with a visual optics experiment that showed how the human eye suffered from chromatic aberration that is corrected in the brain instead of the lens as is normally done outside of biology. While the blue side of the spectrum should give higher resolution do to wavelength it is limited by the relative scarcity of blue cones (2%) versus red (64%) and green (32%) cones. I have always made it a point in my technical schematics to avoid the use of blue where visual acuity was important.
We only had ones because the zeros were too fat to fit through our tiny wires.
You were lucky. We had fat wires but someone didn't screw a terminator down completely on our thinnet and all of our ones leaked out onto the floor. Before we found out, an intern sold them to someone who only had tiny wires . . .
If you would like my suggestion into a few good books on how to do that (if you care) they are:
The Demon Haunted World, Science as a Candle in the Dark - Carl Sagan and Ann Druyan Why People Believe Wierd Things - Michael Schermer Voodoo Science - Robert L. Park
This is a great list. I particularly liked Carl Sagan's book. While it is more relevant to economics, I have to add "Extraordinary Popular Delusions and the Madness of Crowds" by Charles Mackay. While originally copyrighted in 1841, it is very readable today.
It's my understanding that it's illegal in the US, too, unless you're protecting your home against invasion by a burglar.
It varies from jurisdiction to jurisdiction and unfortunately uncertainties like overzealous police and prosecutors can make it risky to rely on even clearly written law. A lot of states have "Stand Your Ground" laws clarifying that lethal self defense may be used even outside of the home and that retreat is not required.
The lesson I learned from CCW class and further study are that defending a third party from immediate harm is permitted. This would include using lethal force to prevent something as indirect as arson to an inhabited building.
Slashdot Mirror
I currently only use the PC version but as far as I know you can SSH into any of the pfsense variations assuming you enable it and have the appropriate firewall rule allowing access. The console only quote for the embedded version probably refers to a lack of display and keyboard support.
You are not getting more energy out then you put in because it has to do with moving heat from one area to another when the temperature difference betweenthe two is relatively low allowing higher efficiency then a straight heater. I probably should have said that the coefficient of performance can be in the 3 to 5 range making it very competetive with gas heating systems. The COP of an electric heater is always 1.
r mance
http://en.wikipedia.org/wiki/Heat_pump
http://en.wikipedia.org/wiki/Coefficient_of_perfo
In the case of computer power supplies that use a rectifier and capacitor combination for AC to DC conversion which is almost all of them, they do not look like an inductive or capacitive load but have a lower power factor caused by drawing current in pulses instead of a sine wave. The result is a higher RMS current then necessary for the load which causes increased line losses and requires higher current capacity for a given power. In extreme cases, distribution transformers can go into saturation causing additional losses.
A power factor of 0.6 does not mean 0.6 watts available for every watt sent. It means the capacity of the line is reduced to 60% of normal do to excessive circulating current. This is easy to see when you look at the rated output power of a typical wall socket, 120 VAC x 15 A = 1800 W, of which you can only use 1100 watts (actually 1080) for a computer load. 1100 watts is the largest common size for inexpensive uninterruptible power supplies for this very reason.
A 0.6 power factor should cause about a 66% increase in line losses for a given load.
Heat pumps can be effectively more then 100% efficient when heating a home however their efficiency goes down as the outside temperature gets colder. Typical numbers are 3 to 5 watt of heat for every watt of power in temperate climates.
Electrically these antennas are still 1/4 wave long through the use of a loading coil at the base which has a detrimental effect on performance. Designing one into a laptop case with acceptable performance do to near field effects would be quite a challenge and entail a lot of compromise.
At the lower end of the VHF band even if the relatively large antenna size approaching 1.5 meters for 1/4 wave was not a problem the useable bandwidth of the antenna would preclude efficient wide frequency operation. The low end of the UHF spectrum above 440 MHz on the other hand would work very well.
By stipulating this, Stallman is implicitly calling for civil disobedience, at least where US law is concerned. Whether you consider that *morally* appropriate in itself is another issue...but what he is effectively saying is that the legal requirements of the GPL v3 are in direct conflict with American law. I am assuming there that the law is one prohibiting reverse engineering of software.
I agree RMS is pushing very hard on the issue of DRM and the DMCA subverting the intent of the GPL but how does the GPL v3 in this case conflict with US law? It seems more like a conflict between copyright and the DMCA. Some manufacturers want to use GPL licensed source code in their products and then use some combination of DRM and the DMCA to effectively defeat one of the purposes of the GPL. If the manufacturer does not agree to the license then it just becomes a copyright issue and they can not legally use the source code in their product. Either they can provide the necessary public key to allow interoperability or they can allow reverse engineering of the hardware. If they wish to keep the system closed then just do not use GPL v3 and similarly licensed software.
From The Ringworld Throne:
1733 AD - Puppeteer Experimentalist regime introduces superconductor plague to Ringworld
- Fall of the Cities
2851 AD - Ringworld
- Lying Bastard shot down and impacts Ringworld
2878 AD - Ringworld Engineers
- Hot Needle of Inquiry reaches Ringworld
Do you mean to say that viruses could be introduced into an organism to change DNA? If so would it be possible for there to be something like inheritance where genetic characteristics propogate directly between organisms rather than through reproduction?
I am not entirely clear what you are asking but there are cases where children express phenotypes controlled by the mother's DNA. In some species of snail, the direction of the child's shell rotation is controlled by the mother's genes.
This is an aspect of perceived recoil which depends not only on bullet velocity, mass, and powder charge but also on how the recoil system operates to distribute the energy over time. Excluding the semiautomatic Webley-Fosbery, revolver barrels are fixed to their frame and tend to have a high center of recoil leading to their sharp upwards movement. When I shoot my old Herter .357 with even less then maximum loads, the slap in my palm and the web of my thumb actually stings. My Thompson Center Contender single shot pistol in .44 magnum or in a medium rifle load is much more pleasant to shoot because of its larger mass, larger rear grip surface area, and lower center of recoil although one needs to be prepared as I discovered when one of my friends tried it and ended up scratching his glasses with the hammer spur. Safely using high power pistols really requires practice in the same way that one would learn any physical skill.
.22 long rifle but depending on the details, a .380 auto using blowback can be much more punishing then 9mm using short recoil despite 9mm being more powerful.
For semiautomatic pistols blowback is much sharper then short recoil. This does not matter for
Isn't -48 still 48Volts of differential, so why not just +48V? I'm no EE, so I'm obviously missing something here.
The voltage is measured with respect to ground and in this case indicates that the positive side is grounded instead of the negative side which most people would be used to. Using a positive ground mitigates corrosion where you have wiring buried in the ground or potentially exposed to the weather.
If you want even more confusion, consider that electron current flow is negative to positive and for historical reasons the arrows used to indicate a PN junction point in the opposite direction.
If you are adept at soldering and use the correct pair order, a section of flat ribbon cable could be used where the door is pinching it.
It was cool. We saw the flash from Missouri.
It could have worked the other way as well. We know the aliens had visited earth earlier so maybe Microsoft licensed Windows to them. This also gives them a great motive for the attack. WGA also pissed me off when it screwed up my system.
P.S. I know Goldblum used a Mac. Why would I let that get in the way of a story about revenge on Microsoft?
I remember Ayn Rand stating in an interview that revolt would be appropriate for defense of the 1st Ammendment but was not able to find a reference and may be misremembering. I consider the following from Unintended Consequences by John Ross to be both more elequent then my own words and more appropriate:
A women is confronted by a big, strong, stranger. She does not know what he is planning, and she is cautious. Getting away from him is not possible. They are in a room and he is standing in front of the only way out, or she is in a wheelchair - whatever. Leaving the area is not an option.
So now he starts to do things she does not like. He asks her for money. She can try to talk him out of it, just like we argue for lower taxes, and maybe it will work. If it does not, and she gets outvoted, she will probably choose to give in to him instead of getting into a fight to the death over ten dollars. You would probably choose to pay your taxes rather then have police arrive to throw you in jail.
Maybe this big man demands some other things, other minor assaults on this woman's dignity. When should she claw at his eyes or shove her ballpoint pen in his throat? When he tries to force her to kiss him? Tries to force her to let him touch her? Tries to force her to have sex with him?
Those are questions that each woman has to answer for herself. There is one situation, though, where I tell the women to fight to the death. That is when the man pulls out a pair of handcuffs and says, "Come on, I promise I won't hurt you, this is just so you won't flail around and hurt either of us by accident. Come on, I just want to talk, get in the van and let me handcuff you to this eyebolt here, and I promise I won't touch you. I'm not asking you to put on a gag or anything, and since you can still scream for help, you know you'll be safe. Come on, I've got a full bar in here, and color TV, and air-conditioning, great stereo, come on, just put on the cuffs."
I tell women that if that ever happens, maybe the man is telling the truth, and maybe after talking to her for a while he will let her go and she will have had a good time drinking champagne and listening to music. But if she gets in the van and puts her wrists in the handcuffs, she has just given up her future ability to fight, and now it is too late.
How do you spot the precise point where a society is standing at the back of the van and the State has the handcuffs out?
- Henry Bowman, May 7, 1973 - Unintended Consequences, John Ross
Hmm... probably a sigma delta ADC?
In a design using semiconductors from about 1970 with little or no integration available for the digital filters required? Delta sigma converters are really good for taking advantage of inexpensive digital logic integration but are only the most recent in a long series of converter architectures.
Single and dual slope integrating as well as various voltage to frequency converter designs were available and with care could have met their requirements for environment and size. TI probably had military temperature range chip sets for them even then. Successive approximation designs would have probably been in multi-chip modules because of the requirement for resistive ratio matching and were popular for military applications but I am not sure when they first came out like that. None of these would have been even close to 20 bits but I think that specification was inaccurate and only reflected the CPU data width. I really enjoy reverse engineering old equipment like this just to understand the designer's mind set.
I found a couple of papers at http://www.microcomputerhistory.com/f14paper.htm with more CPU design details but nothing significant about the converters or signal conditioning. The more I think about it the more I suspect the 20 bit quote was just given because of the data word size and has nothing to do with the actual resolution or linearity which were probably 8 to 10 bits.
That is an interesting read. I wonder how the 20 bit converters were designed. They do not say but if they were used for what would be considered an instrumentation application and had 18 bits of linearity, I would assume some type of charge balancing scheme or single slope integrating. I doubt I could do better then 16 bits on the first shot with a discrete design.
The DMA 32 bit addressing limitations are mostly a function of the memory controller and various expansion devices including some poorly designed or tested PCI cards. Because of the K8's built in memory controller, AMD was in a position to ameliorate this problem to some extent through use of the GART as a limited IOMMU in a standardized way. Intel would have had to build this functionality into its north bridge memory controllers which would have made universal support very difficult never mind third party north bridge support.
Google "iommu AMD gart" or "iommu Intel gart" for more details.
I am somewhat fuzzy on the principle of operation but a very similar setup is used on laminar flow tables and is suppose to significantly reduce any ESD hazard. On the ones I have used, there is a bar at the back of the table within the airflow that has a multitude of insulated sharp charged emitters.
I remember visiting the Exploratorium in San Francisco many years ago (highly recommended) and playing with a visual optics experiment that showed how the human eye suffered from chromatic aberration that is corrected in the brain instead of the lens as is normally done outside of biology. While the blue side of the spectrum should give higher resolution do to wavelength it is limited by the relative scarcity of blue cones (2%) versus red (64%) and green (32%) cones. I have always made it a point in my technical schematics to avoid the use of blue where visual acuity was important.
Can I get off your lawn now?
Sure. Just beware of my Triffid hedge.
We only had ones because the zeros were too fat to fit through our tiny wires.
You were lucky. We had fat wires but someone didn't screw a terminator down completely on our thinnet and all of our ones leaked out onto the floor. Before we found out, an intern sold them to someone who only had tiny wires . . .
If you would like my suggestion into a few good books on how to do that (if you care) they are:
The Demon Haunted World, Science as a Candle in the Dark - Carl Sagan and Ann Druyan
Why People Believe Wierd Things - Michael Schermer
Voodoo Science - Robert L. Park
This is a great list. I particularly liked Carl Sagan's book. While it is more relevant to economics, I have to add "Extraordinary Popular Delusions and the Madness of Crowds" by Charles Mackay. While originally copyrighted in 1841, it is very readable today.
It's my understanding that it's illegal in the US, too, unless you're protecting your home against invasion by a burglar.
It varies from jurisdiction to jurisdiction and unfortunately uncertainties like overzealous police and prosecutors can make it risky to rely on even clearly written law. A lot of states have "Stand Your Ground" laws clarifying that lethal self defense may be used even outside of the home and that retreat is not required.
The lesson I learned from CCW class and further study are that defending a third party from immediate harm is permitted. This would include using lethal force to prevent something as indirect as arson to an inhabited building.
I agree. We need to replace them with the other group of low life scumbags.