I don't understand your bit about slew rates though. Slew rate is limited by the system impedance and the driving electronics. You don't use high frequencies to ensure a slew rate.
Sure you do... imagine a square wave - it's an infinite sum of an infinitely high frequencies at each odd harmonic. As you remove high frequencies the slew rate becomes slower, approaching ultimately a sine wave at the fundamental.
So yes the slew rate is limited by the power that the driver can exert, but also by the frequency response of the transmission line.
But ethernet is a broadband signal with a huge range of frequencies.
No it's not. Ethernet is baseband (manchester coding). It needs very high frequencies to ensure a fast slew rate, but it is not broadband.
The hard limit on length applies only to a given shared segment or collision domain. For switched full duplex, there is no collision domain, so the only limit is signal integrity. 100M is a safe rule of thumb for copper, but with fiber you can go several km.
Aren't the commercial ones also hand made? I find it hard to imagine an automated way of doing it.
Commercial cables have going for them: rubber injection/overmold for more ruggedness, and they're pre-tested. Aside from that, I don't see exactly what should stop you from making decent ones yourself, assuming sufficient skill.
The power boost button is just offloading what the OS should be doing behind the scenes onto the user to rarely get used by most of its users.
So is this like the old 386 boxes that had a Turbo button on the front?
I'm trying to imagine any useful scenario at all. If there's work to do, do it at maximum MHZ. If there's nothing to do, stop and wait for an interrupt. What do you need a button for? Maybe they do not grasp the concept of an event-driven system?
Consider D. Certain people have a reflexive aversion to conservation efforts of any kind, even economically rational ones, and seek to discredit them by any means available, nonsense or otherwise.
I can't speak for all the CFL detractors, but I suspect they are objecting not to its availability but to all the proposals to force people to get rid of their ILs. I use fluorescents for reading, for utility areas, and for workspaces, but I don't want my living room lit up like a hospital, thank you very much. Particularly on Slashdot, people have trouble reconciling environmentalism with libertarian principles, so these "dispassionate" arguments over power factor, mercury, and economics are more palatable.
The utility does not have to *generate* the 28W of "real" power. It just has to *transmit* it (and typically only from the local transformer to the customer, since phase changes can be handled using capacitors when the voltage is down-coverted the last time).
Sort of... the lower power factor means higher losses in transmission. So they don't have to generate the entire 28W, but they do have to generate more than the "apparent" load to compensate the additional loss in transmission.
The utilities might not like to carry the extra amps on their lines, but that isn't the same as them having to generate more power.
You are absolutely wrong. The additional current increases the resistive losses on the transmission lines. Hence for a lower power factor, more energy must be generated to deliver a given amount of watts.
Interesting - this is a pretty serious blow to the CFL concept, and if they're really that bad, I'm surprised why it's taken this long for it to come up. Maybe it's fixable but I doubt it could be done without adding significant cost to the bulbs.
A mechanical analogy to help you understand power factor: say you have a weight on the end of a wooden stick. You lift the stick up and down and the weight moves. You are transferring energy efficiently. Now change the stick to a spring. You can still move the weight up and down but it moves a lot less for a given amplitude. Now it may seem that no energy is lost because the spring is returning the energy to the source on each cycle, but in fact it is being lost because of the resistance in the distribution line. The loss is incurred by the power company even if it doesn't appear on your meter.
Power factor is the reason UPSes are rated in volt-amps instead of watts. Switching power supplies usually have power factors significantly less than 1.0, so it's the VA that matters.
In my direct experience, they are highly-skilled in copying/ripping off and even building on/improving on original ideas. Note: This is for stuff which is often already trademarked, registered and patented.
OTOH, it sounds like he's not looking for some revolutionary hardware design, indeed he might modify an existing design.
In my experience manufacturing in China, I have not had any problems with knockoffs (although that has happened in the USA!). However, my products have always had their special sauce in the software/firmware. Software is protected by copyright and even if someone in China clones your product, they will not be able to sell it in the US or Europe.
It's much easier to defend yourself with copyright law than with patents. On that note, file a provisional patent - just write up how it works in your own words, and get a lawyer to file it for you. Personally I would not go any further than that. This evidences when you had the idea, and even though it's much less than an actual, issued patent, having it on file can go a long way in the future if you need to fend of a patent on validity grounds.
So, I'd suggest getting some VC/angel financing and professional help, and patent your idea to hell and back in major markets before doing anything else. OK, they'll take a huge chunk of the eventual gain, but 50% of something is a lot better than 100% of nothing.
Especially in this economy, I would not be out trying to raise money. And in general, you need to be very careful about slicing up your cap chart right off the bat. Get as far as you can on your software work and build a solid proof of concept first. Hopefully you can fund that yourself or moonlight it. By then you'll have a better idea what you'll need to get off the ground.
They're trying to get people to rush out and buy black cars to stimulate the economy and get some tax revenue. Black cars are better than no cars, which is what's being sold in California right now.
It would be like a oil change shop offering free coffee to customers (and many do), but reusing the same disposable paper filter over and over (none do this, in my experience).
The average Joe, who just buys a WRT54G (aka: black box) from Wal-Mart, plugs it into his cable modem, and logs into the "linksys" SSID from his laptop isn't affected by this worm, since the default configuration doesn't allow remote access from the Internet at all.
But it does allow access from the LAN side, so all that takes is one owned client connecting to that AP. It could even spread via laptops physically roaming to different hotspots (maybe not AT&T etc, but think of an independent coffee shop owner who should not have to be a networking guru).
Routers seem like a nice prize indeed. Always connected and on a public IP, and there's millions of them!. I'm surprised it's taken this long.
It's hard enough for most people to just hook one of these up, much less wipe a rootkit from it.
It's not that I'd rather not know, it's that I'm not going to implant stuff in my body or strap things to my wrist to find out. That's a rather different prospect than installing a smoke detector, dontcha think?
I can imagine a future society where your attitude would be considered a threat to public health and forceful measures to protect US from YOU.
Gosh yes, imagine a world where it's illegal to ride a bike unless you are wearing a proper helmet approved by a government designated regulatory agency, or to drive your car without wearing your seatbelt, or to smoke a cigarette or a joint in the privacy of your own home. Or where you're required by the state to buy overpriced insurance whether you want it or not. Where the state disciplines you for disciplining your kid, where restaurants are forbidden from serving certain tasty yet unhealthy ingredients, where every product and every place of business is clearly labeled concerning the possible risks of cancer. Oh, heaven forfend that this might spiral into such lunacy!
Did you ever stop to think how silly and also how dangerous it is to live our lives with absolutely no monitoring of our body's medical status?
I think it's silly how people constantly try to eliminate every imaginable element of risk from their lives instead of just getting out there and living it. I find the idea of having my physiology constantly monitored by a computer about as attractive as living in a big plastic bubble. But hey if what you want out of modern medicine is to be protected by layer after layer of prophylactics so you can feel safe, by all means go for it.
Suppose I agree that protecting all of AIG's insured parties was absolutely necessary. We could have done that through bankruptcy proceedings. We could still have fed that money into the system in a controlled manner, without leaving the foxes in charge of the hen-house. We did not have to give them billions with no strings attached.
This issue is that we are rewarding the people in power for fucking us over. What we need to get the bad guys out and provide proper incentives for a new team to replace them. Instead what we're doing is paying them a handsome sum to keep doing what they're doing. Indeed, the cost to us is much larger than these individuals' compensation!
Obama says "blame me", which is political-speak for "screw you, it's done, get over it". He won't be saying "blame me" when the honeymoon is over and this escalates to a full scale popular revolt.
We KNEW AIG were crooks long before we gave them this money. Why did they do it? Where the fuck was the outrage when these bailouts were first suggested? I've been outraged since the beginning, because the whole game plan has been obvious to me since they robbed us of that first $700B. And yet polls suggest that Americans STILL think this is going to work somehow.
These people: the Congress, the President, AIG, are all just a bunch of god damned frat boys, scratching each other's backs and doling out our tax money to each other in such staggering volumes that it WILL be the end of this country if we don't stop right now.
Did you all catch Chris Dodd saying he had nothing to do with the change in the bailout legislation to allow these bonuses, then the next day saying oops, that was me. "Somebody should have caught it sooner" - yeah, right, if the bill had any chance of being reviewed by the legislators themselves, let alone the public, before if slipped past Obama's desk quicker than a greased turd. What happened to those 5 days, huh?
Seriously people, at what point do we get off the couch and take back this country? Obama can stimulate my ass.
This is not a hard problem. You can not maintain a reasonable oversell ratio unless you have low average usage. Yes, one way to get that is throttling, but it's difficult to do that in an effective way that won't piss off your customers.
What you should do is tell them they get 40G/mo or whatever, plus a usage fee above that, and let the customers throttle themselves if they want to. If you want to be a nice guy about it, you could give them the option of being auto-throttled or suspended if they approach the limit, so they don't get an unexpected bill. Of course whatever you do, you'll need to revise your terms of service.
Voila, you maintain low pricing and good performance for everyone, because the p2p guys will police themselves now. If you have customers that routinely transmit hundreds of GB because they're a professional video editor or something, then they won't mind paying for the bandwidth.
How does a person get their money out of these numbered accounts? What recourse does a person have if the bank refuses to hand over their money?
It's called trust. The Swiss banking system has earned it over the course of more than three hundred years. Honestly, where do you think your dough is safer: a numbered Swiss account, or an American account with your name on it?
Not everyone who has accounts in a different country is doing so to cheat on taxes. If you're really loaded it would stupid not to spread the risk across multiple countries/banks, to minimize your exposure to precisely the kind of clusterfuck that's happening now.
Slashdot Mirror
I used to work for a company that builds large machines to do exactly that.
Link?
I don't understand your bit about slew rates though. Slew rate is limited by the system impedance and the driving electronics. You don't use high frequencies to ensure a slew rate.
Sure you do... imagine a square wave - it's an infinite sum of an infinitely high frequencies at each odd harmonic. As you remove high frequencies the slew rate becomes slower, approaching ultimately a sine wave at the fundamental.
So yes the slew rate is limited by the power that the driver can exert, but also by the frequency response of the transmission line.
To see this consult an FFT near you (just the first plot).
Great link!
But ethernet is a broadband signal with a huge range of frequencies.
No it's not. Ethernet is baseband (manchester coding). It needs very high frequencies to ensure a fast slew rate, but it is not broadband.
The hard limit on length applies only to a given shared segment or collision domain. For switched full duplex, there is no collision domain, so the only limit is signal integrity. 100M is a safe rule of thumb for copper, but with fiber you can go several km.
Aren't the commercial ones also hand made? I find it hard to imagine an automated way of doing it.
Commercial cables have going for them: rubber injection/overmold for more ruggedness, and they're pre-tested. Aside from that, I don't see exactly what should stop you from making decent ones yourself, assuming sufficient skill.
The power boost button is just offloading what the OS should be doing behind the scenes onto the user to rarely get used by most of its users.
So is this like the old 386 boxes that had a Turbo button on the front?
I'm trying to imagine any useful scenario at all. If there's work to do, do it at maximum MHZ. If there's nothing to do, stop and wait for an interrupt. What do you need a button for? Maybe they do not grasp the concept of an event-driven system?
Why don't you just wind it down and give the money back to your shareholders? Or stick to servers.
Consider D. Certain people have a reflexive aversion to conservation efforts of any kind, even economically rational ones, and seek to discredit them by any means available, nonsense or otherwise.
I can't speak for all the CFL detractors, but I suspect they are objecting not to its availability but to all the proposals to force people to get rid of their ILs. I use fluorescents for reading, for utility areas, and for workspaces, but I don't want my living room lit up like a hospital, thank you very much. Particularly on Slashdot, people have trouble reconciling environmentalism with libertarian principles, so these "dispassionate" arguments over power factor, mercury, and economics are more palatable.
The utility does not have to *generate* the 28W of "real" power. It just
has to *transmit* it (and typically only from the local transformer to the
customer, since phase changes can be handled using capacitors when the voltage
is down-coverted the last time).
Sort of... the lower power factor means higher losses in transmission. So they don't have to generate the entire 28W, but they do have to generate more than the "apparent" load to compensate the additional loss in transmission.
The utilities might not like to carry the extra amps on their lines, but that isn't the same as them having to generate more power.
You are absolutely wrong. The additional current increases the resistive losses on the transmission lines. Hence for a lower power factor, more energy must be generated to deliver a given amount of watts.
Interesting - this is a pretty serious blow to the CFL concept, and if they're really that bad, I'm surprised why it's taken this long for it to come up. Maybe it's fixable but I doubt it could be done without adding significant cost to the bulbs.
A mechanical analogy to help you understand power factor: say you have a weight on the end of a wooden stick. You lift the stick up and down and the weight moves. You are transferring energy efficiently. Now change the stick to a spring. You can still move the weight up and down but it moves a lot less for a given amplitude. Now it may seem that no energy is lost because the spring is returning the energy to the source on each cycle, but in fact it is being lost because of the resistance in the distribution line. The loss is incurred by the power company even if it doesn't appear on your meter.
Power factor is the reason UPSes are rated in volt-amps instead of watts. Switching power supplies usually have power factors significantly less than 1.0, so it's the VA that matters.
Intravenous caffeine is available as a drug and I will give it to patients in a dose of 250-500 mg.
scrip please!
In my direct experience, they are highly-skilled in copying/ripping off and even building on/improving on original ideas. Note: This is for stuff which is often already trademarked, registered and patented.
OTOH, it sounds like he's not looking for some revolutionary hardware design, indeed he might modify an existing design.
In my experience manufacturing in China, I have not had any problems with knockoffs (although that has happened in the USA!). However, my products have always had their special sauce in the software/firmware. Software is protected by copyright and even if someone in China clones your product, they will not be able to sell it in the US or Europe.
It's much easier to defend yourself with copyright law than with patents. On that note, file a provisional patent - just write up how it works in your own words, and get a lawyer to file it for you. Personally I would not go any further than that. This evidences when you had the idea, and even though it's much less than an actual, issued patent, having it on file can go a long way in the future if you need to fend of a patent on validity grounds.
So, I'd suggest getting some VC/angel financing and professional help, and patent your idea to hell and back in major markets before doing anything else. OK, they'll take a huge chunk of the eventual gain, but 50% of something is a lot better than 100% of nothing.
Especially in this economy, I would not be out trying to raise money. And in general, you need to be very careful about slicing up your cap chart right off the bat. Get as far as you can on your software work and build a solid proof of concept first. Hopefully you can fund that yourself or moonlight it. By then you'll have a better idea what you'll need to get off the ground.
They're trying to get people to rush out and buy black cars to stimulate the economy and get some tax revenue. Black cars are better than no cars, which is what's being sold in California right now.
I'm not sure if I'm kidding or not here.
It would be like a oil change shop offering free coffee to customers (and many do), but reusing the same disposable paper filter over and over (none do this, in my experience).
That's what they do with your old oil filter.
The average Joe, who just buys a WRT54G (aka: black box) from Wal-Mart, plugs it into his cable modem, and logs into the "linksys" SSID from his laptop isn't affected by this worm, since the default configuration doesn't allow remote access from the Internet at all.
But it does allow access from the LAN side, so all that takes is one owned client connecting to that AP. It could even spread via laptops physically roaming to different hotspots (maybe not AT&T etc, but think of an independent coffee shop owner who should not have to be a networking guru).
Routers seem like a nice prize indeed. Always connected and on a public IP, and there's millions of them!. I'm surprised it's taken this long.
It's hard enough for most people to just hook one of these up, much less wipe a rootkit from it.
It's not that I'd rather not know, it's that I'm not going to implant stuff in my body or strap things to my wrist to find out. That's a rather different prospect than installing a smoke detector, dontcha think?
I can imagine a future society where your attitude would be considered a threat to public health and forceful measures to protect US from YOU.
Gosh yes, imagine a world where it's illegal to ride a bike unless you are wearing a proper helmet approved by a government designated regulatory agency, or to drive your car without wearing your seatbelt, or to smoke a cigarette or a joint in the privacy of your own home. Or where you're required by the state to buy overpriced insurance whether you want it or not. Where the state disciplines you for disciplining your kid, where restaurants are forbidden from serving certain tasty yet unhealthy ingredients, where every product and every place of business is clearly labeled concerning the possible risks of cancer. Oh, heaven forfend that this might spiral into such lunacy!
Did you ever stop to think how silly and also how dangerous it is to live our lives with absolutely no monitoring of our body's medical status?
I think it's silly how people constantly try to eliminate every imaginable element of risk from their lives instead of just getting out there and living it. I find the idea of having my physiology constantly monitored by a computer about as attractive as living in a big plastic bubble. But hey if what you want out of modern medicine is to be protected by layer after layer of prophylactics so you can feel safe, by all means go for it.
Suppose I agree that protecting all of AIG's insured parties was absolutely necessary. We could have done that through bankruptcy proceedings. We could still have fed that money into the system in a controlled manner, without leaving the foxes in charge of the hen-house. We did not have to give them billions with no strings attached.
We are in violent agreement then!
Actually, you and XKCD are missing the point.
This issue is that we are rewarding the people in power for fucking us over. What we need to get the bad guys out and provide proper incentives for a new team to replace them. Instead what we're doing is paying them a handsome sum to keep doing what they're doing. Indeed, the cost to us is much larger than these individuals' compensation!
Obama says "blame me", which is political-speak for "screw you, it's done, get over it". He won't be saying "blame me" when the honeymoon is over and this escalates to a full scale popular revolt.
We KNEW AIG were crooks long before we gave them this money. Why did they do it? Where the fuck was the outrage when these bailouts were first suggested? I've been outraged since the beginning, because the whole game plan has been obvious to me since they robbed us of that first $700B. And yet polls suggest that Americans STILL think this is going to work somehow.
These people: the Congress, the President, AIG, are all just a bunch of god damned frat boys, scratching each other's backs and doling out our tax money to each other in such staggering volumes that it WILL be the end of this country if we don't stop right now.
Did you all catch Chris Dodd saying he had nothing to do with the change in the bailout legislation to allow these bonuses, then the next day saying oops, that was me. "Somebody should have caught it sooner" - yeah, right, if the bill had any chance of being reviewed by the legislators themselves, let alone the public, before if slipped past Obama's desk quicker than a greased turd. What happened to those 5 days, huh?
Seriously people, at what point do we get off the couch and take back this country? Obama can stimulate my ass.
This is not a hard problem. You can not maintain a reasonable oversell ratio unless you have low average usage. Yes, one way to get that is throttling, but it's difficult to do that in an effective way that won't piss off your customers.
What you should do is tell them they get 40G/mo or whatever, plus a usage fee above that, and let the customers throttle themselves if they want to. If you want to be a nice guy about it, you could give them the option of being auto-throttled or suspended if they approach the limit, so they don't get an unexpected bill. Of course whatever you do, you'll need to revise your terms of service.
Voila, you maintain low pricing and good performance for everyone, because the p2p guys will police themselves now. If you have customers that routinely transmit hundreds of GB because they're a professional video editor or something, then they won't mind paying for the bandwidth.
How does a person get their money out of these numbered accounts? What recourse does a person have if the bank refuses to hand over their money?
It's called trust. The Swiss banking system has earned it over the course of more than three hundred years. Honestly, where do you think your dough is safer: a numbered Swiss account, or an American account with your name on it?
Not everyone who has accounts in a different country is doing so to cheat on taxes. If you're really loaded it would stupid not to spread the risk across multiple countries/banks, to minimize your exposure to precisely the kind of clusterfuck that's happening now.