The idea of three phase DC is a bit difficult to get your head around. I wasn't suggesting three phase DC (which as you say would be crazy) merely mentioning common standards as part of pointing out how much we rely on voltage convertion.
The exact standard would have to be changed a bit for DC instead of AC. The main point though is that voltages that are safe enough to use in the home are not efficiant enough for transmitting any signifiant distance.
DC power is actually slightly less efficient than three phase power (15% less) than three phase AC. My nieve analysis makes it 25%, assuming that the RMS line-line voltage and the total ammount of copper used stays the same and we neglect capacitive and inductive effects.
but that nieve analysis misses three things 1: it is the line-ground voltage that we really care about not the line-line voltage because the pole the lines are attatched to/the armour surrounding the lines is at ground. If we make the line-ground voltage rather than the line-line voltage the same then the "advantage" of three phase dissapears. 2: insulator performance tends to depend on the peak voltage not the RMS voltage. If it is the line-ground peak voltage we make the same DC wins by a large margin. 3: inductive and capacitive effects can be significant.
HVDC is viable because it is easier to bump up the voltage with only two conductors to isolate than three. That is certainly an advantage but I think the elimination of capacitive and inductive effects and the higher RMS voltage for a given peak voltage (for DC peak=rms, for AC peak=RMS*sqrt(2) ) are more significant.
some data centers are moving to converting from AC to DC outside of the cases and transporting DC directly to the servers. Datacenters are an unusual case in that they like to have everything on tightly controlled backup systems. Those that don't use DC to the servers tend to have AC-DC-AC double conversion as part of their UPS systems.
Telcos have used DC for years so the batteries can sit directly on the main power distribution busses.
wireless power transmission is possible but not at efficiancies that makes it usefull for anything more than extremely low power items (like your crystal radio). Teslas ideas of large scale wireless power distribution were a pipe dream.
DC doesn't require high voltages, a DC line at a given voltage is slightly more efficiant than an AC line of the same voltage.
DC has two main problems
1: it is a pain to voltage convert. Voltage conversion is pretty vital to our modern use of electricity, you don't want 11KV in your home but you don't want to be transmitting 240/415 three phase or worse 120/240 split phase any significant distance. You also want much lower voltages for loads of equipment.
For equipment power supplies it isn't so bad, they generally don't have particularlly high efficiancies anyway, they tend to run at fairly low power and they tend to be in a nice indoor environment but building a DC equivilent of a pole pig with similar efficiancy and reliability would get pretty expensive.
2: DC is a pain to switch, switches and breakers would have to be either much bigger or much more complex for a given DC voltage than for the same AC voltage (the zero crossings of AC tend to break arcs).
DC is still far more of a pain to convert than AC at least if you want high efficiancy and high reliability. While HVDC is certainly more efficiant for very long or undersea transmission lines it would be extremely difficult to build a power distribution grid based on it.
Power can be made is so many ways It can but making it dependablly day in day out is hard, covering the peaks in demand is even harder.
Most renewables (dam based hydro is the main exception but finding sites for that which are both geologically suitable and don't involve flooding loads of peoples homes is very hard so while it is a major contributor to current electricity generation it has little potential for growth) don't provide either a base load or a peaking supply making thier utility to the power grid relatively low. Solar and wind generate depending on the whims of the weather. Run of the river hydro systems generate in a pattern that depends on the natural behaviour of the water body they are in.
Getting renewables other than dam based hydro up to 10% maybe even 20% of electricity production is reasonable but that will probablly do little more than make up for demand growth. Getting them any higher than that is liable to be extremely difficult because of the issues I mentioned above.
All that really leaves is fossil fuels and nuclear.
Nuclear is poor at peak covering but at least it can take on the base loads and it's predictability means you can easilly work out the ammount of pumped storage or hydrogen based storage or similar you need to cover the peaks.
You can't gloss over the disposal issue like that. The big disposal issue seems to be that we hold anything nuclear to insanely high standards. We produce lots of nasty chemical waste that will stay dangerous practically forever too and yet we don't treat that with anywhere near the paranioa we treat nuclear waste with.
Also when the US gets over it's fear of reprocessing do you really want to have put the "waste" somewhere you can't easilly get it back from?
natural gas is clean burning It is clean in the sense that there is far less unwanted crap in it than in many other fossil fuels (and the stuff that is there is easier to clean out) but there is still the problem of releasing large ammounts of dino-carbon into the short term carbon cycle.
Drop activation. At the very least, go back to offering a corporate version which doesn't require activation. In some ways at least for those licensed to use it the vista volume activation system is better than the situation with XP VLKs.
With an XP VLK you either have to make sure you don't let WGA on any of your machines (tricky if some of them are unmanaged) or that your key is carefully gaurded. Otherwise when your key leaks your machines can end up failing WGA checks and you can end up going round rekeying every machine.
Of course with XP MS pulled a bait and switch, they intitially made XP one time activation for normal users and free of any checks for VLK users, then later they started trying to ram WGA down users throats (it appears as a critical update and even if you reject it it reappears later).
with vista you just activate one of your vista machines as a KMS, make sure it is firewalled from the internet and correctly entered into your internal dns and then it takes care of activating all your other machines without you having to enter product keys on them. No need to let your build/repair people have any keys and therefore no chance of them leaking any keys.
The problem is when you get an outage of utility power, the servers keep up on first UPS then generator. The aircon goes down and then should come back up when the generators come online but if something goes wrong and the aircon power stays out then there is a problem.
What is really meant is that as far as the OS is concerned a file is just a sequence of bytes. The OS and filesystem drivers do not concern themselves with what those bytes mean only with storing them and associating them with an identifier for retrival and security information.
That is if an application stores a sequence of bytes it expects to get the same sequence back, not have the driver interpret the file, store it's interpretation of it and then regenerate a different sequence of bytes from that interpretation.
I'd want to see a few years of test data before I believed such reliability data though! And make sure those tests are done on a poorly maintained car.
Fly by wire airliners are safe enough because of a combination of redundant design and rigerous maintainance. I bet many cars don't visit a garage at all unless they actually break down.
I'm pretty sure that cars exist/are planned that use "drive by wire" Concept cars have certainly been made that work that way, but afaict they have not reached production because of the danger thwy would pose if badly maintained.
No big deal, just use a 64 bit location for each word and ignore the higher bits. You will have to calculate the status flags manually but any emulator written in a high level language tends to have to do that anyway so no big deal.
Who pays to maintain the wire The customers either directly to those who operate the wire or indirectly via those who sell services on the wire.
and who's job is it to do the maintaining? an entity which is regulated to ensure that their ONLY responsibility is to maintain expand and operate the physical infrastructure. Probablly a nonprofit set up by local government would make most sense.
Roads are publicly funded. Should the telecom physical layer do the same? Should property taxes also apply to data transmission lines? Public funding may be nessacery to cover the startup costs if it is not feasible to wrestle the existing infrastructure from those who currently use it to further other monopolies/cartels but once running I would imagine the ongoing costs could be covered easilly enough by usage fees.
Roads are different because thier use is very hard to meter and pretty much everyone uses them (though to different degrees) so it makes sense to charge local roads to local property owners through property taxes.
I bet a really hungry cat would move on to the eating stage at that point. A pet cat probablly just preffers the food it's owners gives it to the food it can catch itself.
well serial ports don't really support plug and play (iirc windows does autodetect serial mice but even that is a bit of a hack) so i'm not surprised it wasn't autodetected.
looks like it is pretty easy to install a serial modem on vista though, if you go into the add hardware menu and select the automatic option and it fails to find anything it automatically takes you to a list of device types. Select modem you will again get an autodetection screen and again if autodetection fails it will give you a list to choose from including a "standard 56000 bps modem" entry.
But if what you say is true and the surgery is now allowed, I might reconsider my decision and go for some Lasik From what I can gather if you ever want to be a military pilot that is a bad idea.
My understanding is that most navies that allow laser eye surgery only allow it if they did it.
Afaict those who got rich at google got rich because they got thier stock options at the right time to take advatage of the stock skyrocketing. The same thing happened to many early employees at microsoft.
This masseuse becoming a multimillionaire is pretty much like one who wins the lottery, she didn't earn the money she just got lucky.
it isn't an easy practice to know how far a group of overly optimistic speculators can raise the price of a company's stock. Sell too soon and you've given up potentially large profits, hold too long and potentially wind up with a loss. In other words investing like this is essentially gambling.
Slashdot Mirror
making your event listeners weak references would kinda screw things up when an objects only job was to listen to events.
The idea of three phase DC is a bit difficult to get your head around.
I wasn't suggesting three phase DC (which as you say would be crazy) merely mentioning common standards as part of pointing out how much we rely on voltage convertion.
The exact standard would have to be changed a bit for DC instead of AC. The main point though is that voltages that are safe enough to use in the home are not efficiant enough for transmitting any signifiant distance.
DC power is actually slightly less efficient than three phase power (15% less) than three phase AC.
My nieve analysis makes it 25%, assuming that the RMS line-line voltage and the total ammount of copper used stays the same and we neglect capacitive and inductive effects.
but that nieve analysis misses three things
1: it is the line-ground voltage that we really care about not the line-line voltage because the pole the lines are attatched to/the armour surrounding the lines is at ground. If we make the line-ground voltage rather than the line-line voltage the same then the "advantage" of three phase dissapears.
2: insulator performance tends to depend on the peak voltage not the RMS voltage. If it is the line-ground peak voltage we make the same DC wins by a large margin.
3: inductive and capacitive effects can be significant.
HVDC is viable because it is easier to bump up the voltage with only two conductors to isolate than three.
That is certainly an advantage but I think the elimination of capacitive and inductive effects and the higher RMS voltage for a given peak voltage (for DC peak=rms, for AC peak=RMS*sqrt(2) ) are more significant.
some data centers are moving to converting from AC to DC outside of the cases and transporting DC directly to the servers.
Datacenters are an unusual case in that they like to have everything on tightly controlled backup systems. Those that don't use DC to the servers tend to have AC-DC-AC double conversion as part of their UPS systems.
Telcos have used DC for years so the batteries can sit directly on the main power distribution busses.
wireless power transmission is possible but not at efficiancies that makes it usefull for anything more than extremely low power items (like your crystal radio). Teslas ideas of large scale wireless power distribution were a pipe dream.
DC doesn't require high voltages, a DC line at a given voltage is slightly more efficiant than an AC line of the same voltage.
DC has two main problems
1: it is a pain to voltage convert. Voltage conversion is pretty vital to our modern use of electricity, you don't want 11KV in your home but you don't want to be transmitting 240/415 three phase or worse 120/240 split phase any significant distance. You also want much lower voltages for loads of equipment.
For equipment power supplies it isn't so bad, they generally don't have particularlly high efficiancies anyway, they tend to run at fairly low power and they tend to be in a nice indoor environment but building a DC equivilent of a pole pig with similar efficiancy and reliability would get pretty expensive.
2: DC is a pain to switch, switches and breakers would have to be either much bigger or much more complex for a given DC voltage than for the same AC voltage (the zero crossings of AC tend to break arcs).
DC is still far more of a pain to convert than AC at least if you want high efficiancy and high reliability. While HVDC is certainly more efficiant for very long or undersea transmission lines it would be extremely difficult to build a power distribution grid based on it.
Power can be made is so many ways
It can but making it dependablly day in day out is hard, covering the peaks in demand is even harder.
Most renewables (dam based hydro is the main exception but finding sites for that which are both geologically suitable and don't involve flooding loads of peoples homes is very hard so while it is a major contributor to current electricity generation it has little potential for growth) don't provide either a base load or a peaking supply making thier utility to the power grid relatively low. Solar and wind generate depending on the whims of the weather. Run of the river hydro systems generate in a pattern that depends on the natural behaviour of the water body they are in.
Getting renewables other than dam based hydro up to 10% maybe even 20% of electricity production is reasonable but that will probablly do little more than make up for demand growth. Getting them any higher than that is liable to be extremely difficult because of the issues I mentioned above.
All that really leaves is fossil fuels and nuclear.
Nuclear is poor at peak covering but at least it can take on the base loads and it's predictability means you can easilly work out the ammount of pumped storage or hydrogen based storage or similar you need to cover the peaks.
You can't gloss over the disposal issue like that.
The big disposal issue seems to be that we hold anything nuclear to insanely high standards. We produce lots of nasty chemical waste that will stay dangerous practically forever too and yet we don't treat that with anywhere near the paranioa we treat nuclear waste with.
Also when the US gets over it's fear of reprocessing do you really want to have put the "waste" somewhere you can't easilly get it back from?
natural gas is clean burning
It is clean in the sense that there is far less unwanted crap in it than in many other fossil fuels (and the stuff that is there is easier to clean out) but there is still the problem of releasing large ammounts of dino-carbon into the short term carbon cycle.
Drop activation. At the very least, go back to offering a corporate version which doesn't require activation.
In some ways at least for those licensed to use it the vista volume activation system is better than the situation with XP VLKs.
With an XP VLK you either have to make sure you don't let WGA on any of your machines (tricky if some of them are unmanaged) or that your key is carefully gaurded. Otherwise when your key leaks your machines can end up failing WGA checks and you can end up going round rekeying every machine.
Of course with XP MS pulled a bait and switch, they intitially made XP one time activation for normal users and free of any checks for VLK users, then later they started trying to ram WGA down users throats (it appears as a critical update and even if you reject it it reappears later).
with vista you just activate one of your vista machines as a KMS, make sure it is firewalled from the internet and correctly entered into your internal dns and then it takes care of activating all your other machines without you having to enter product keys on them. No need to let your build/repair people have any keys and therefore no chance of them leaking any keys.
and eliminate the competition while they are at it...
The problem is when you get an outage of utility power, the servers keep up on first UPS then generator. The aircon goes down and then should come back up when the generators come online but if something goes wrong and the aircon power stays out then there is a problem.
The thing is for better or worse network centers have ended up in city centers, the further you are from those centers the more your connections cost.
What is really meant is that as far as the OS is concerned a file is just a sequence of bytes. The OS and filesystem drivers do not concern themselves with what those bytes mean only with storing them and associating them with an identifier for retrival and security information.
That is if an application stores a sequence of bytes it expects to get the same sequence back, not have the driver interpret the file, store it's interpretation of it and then regenerate a different sequence of bytes from that interpretation.
the one feature they've added this century that is actually useful.
Well it would have been if they hadn't done a half arsed job of it.
I'd want to see a few years of test data before I believed such reliability data though!
And make sure those tests are done on a poorly maintained car.
Fly by wire airliners are safe enough because of a combination of redundant design and rigerous maintainance. I bet many cars don't visit a garage at all unless they actually break down.
I'm pretty sure that cars exist/are planned that use "drive by wire"
Concept cars have certainly been made that work that way, but afaict they have not reached production because of the danger thwy would pose if badly maintained.
No big deal, just use a 64 bit location for each word and ignore the higher bits. You will have to calculate the status flags manually but any emulator written in a high level language tends to have to do that anyway so no big deal.
Who pays to maintain the wire
The customers either directly to those who operate the wire or indirectly via those who sell services on the wire.
and who's job is it to do the maintaining?
an entity which is regulated to ensure that their ONLY responsibility is to maintain expand and operate the physical infrastructure. Probablly a nonprofit set up by local government would make most sense.
Roads are publicly funded. Should the telecom physical layer do the same? Should property taxes also apply to data transmission lines?
Public funding may be nessacery to cover the startup costs if it is not feasible to wrestle the existing infrastructure from those who currently use it to further other monopolies/cartels but once running I would imagine the ongoing costs could be covered easilly enough by usage fees.
Roads are different because thier use is very hard to meter and pretty much everyone uses them (though to different degrees) so it makes sense to charge local roads to local property owners through property taxes.
I bet a really hungry cat would move on to the eating stage at that point. A pet cat probablly just preffers the food it's owners gives it to the food it can catch itself.
well serial ports don't really support plug and play (iirc windows does autodetect serial mice but even that is a bit of a hack) so i'm not surprised it wasn't autodetected.
looks like it is pretty easy to install a serial modem on vista though, if you go into the add hardware menu and select the automatic option and it fails to find anything it automatically takes you to a list of device types. Select modem you will again get an autodetection screen and again if autodetection fails it will give you a list to choose from including a "standard 56000 bps modem" entry.
But if what you say is true and the surgery is now allowed, I might reconsider my decision and go for some Lasik
From what I can gather if you ever want to be a military pilot that is a bad idea.
My understanding is that most navies that allow laser eye surgery only allow it if they did it.
Afaict those who got rich at google got rich because they got thier stock options at the right time to take advatage of the stock skyrocketing. The same thing happened to many early employees at microsoft.
This masseuse becoming a multimillionaire is pretty much like one who wins the lottery, she didn't earn the money she just got lucky.
it isn't an easy practice to know how far a group of overly optimistic speculators can raise the price of a company's stock. Sell too soon and you've given up potentially large profits, hold too long and potentially wind up with a loss.
In other words investing like this is essentially gambling.