Two half-adders (plus an OR gate to combine carries) make a full adder, but a "full adder" and a "full computer" are two completely different things. You can put together a bunch of full adders to make a multi-bit adder. Add more logic to perform subtractions, shifts, plus logical and, or, and not operations, and you've got a nice little ALU. Now add some registers, a control store, instruction decoding logic, and a sequencer (complete with conditional branching logic), and you've got a CPU. And to build a computer, add memory and some kind of I/O.
I'd call that a good bit more than twice as many dominos.
wait a minute why would Americans want socialized healthcare?
For the answer, read this op-ed piece about why the current system is so screwed up, and what can be done about it. I don't think the column goes far enough, though; it gives all the reasons for going to a single-payer system but stops short of calling for one.
Amen. Classic rock is a dumbing-down of AOR. AOR was a dumbing-down of the progressive format. Most of the non-classical part of my music collection (400 or so CDs, at a rough guess, and a couple hundred old LPs and tapes) could find play on either a progressive or AOR station, but much of it would never be found on today's radio. Genesis before Phil Collins took over? Pink Floyd pre-DSotM? The Nice? King Crimson? Soft Machine? Forget it!
I hope you're wrong about satellite radio because I'd like to try it out sometime.
In the early seventies there were progressive radio stations (mostly on FM) that would just play whatever the DJ liked, usually but not limited to progressive rock, and always out of the ordinary. Often they would play an entire side of an LP uninterrupted. Everything you heard was something you'd never hear on the AM top-40 stations. Sadly, this format was displaced by AOR stations playing automated playlists circa 1975, and later, classic rock stations playing Smoke on the Water and China Grove how many times per day. It's never been the same.
any legislation is another step to the government fully regulating and controling the Internet
I'm sorry, but that's just a non sequitur. Regulating service providers is not the same as "controling the Internet". The latter would imply that the government monitors all Internet traffic and create and enforce its own policies regarding that traffic. Which, by definition, is another form of non-neutrality.
80 Gb/s would be the half-duplex bandwidth. Full duplex is 160 Gb/s (if you can find an application to utilize all of both directions). PCIe uses an encoding of 10 bits to the byte, for numerous technical reasons but primarily to maintain a DC balance (50% ones, 50% zeros) and to ensure maximum run lengths so that the clock (embedded in the serial stream) can be recovered at the receiving end. 160/10 = 16 GB/s.
16 Gigabits per second (Gb/s or Gbps, not gpbs) on an x16 would be 1 Gb/s per lane. This spec
goes to 5 Gb/s per lane (per direction), so your figure is off by a factor of 5 (or 10, if
you consider the case of both directions simultaneously saturated).
The reason it's 16 (for full duplex) and not 20 is that 8b10b encoding requires 10 bits on the serial link to encode 1 byte of data.
Several people have answered this already, but I'll just add a few small points.
Configuration space in PCI Express is a superset of PCI's configuration space. So a BIOS or OS that can talk to config registers on a PCI device can talk to config registers on a PCIe
device.
Also, the transaction layer mode (split transactions) is based on the PCI-X (not conventional PCI) model.
You can think of the relationship between PCI and PCIe as similar to that between parallel SCSI and the serial interfaces that implement the SCSI command sets (SAS, iSCSI, and FC).
Gigatransfers/second. I think somebody on the committee thought Gigabits/second was underselling the bandwidth, since it only represents the bandwidth of one lane in a multilane link. So a "transfer" is the number of bits that can be moved simultaneously over all the lanes in a UI (unit interval, which is 0.2 ns at the new rate); consequently the size of a transfer will vary with the link width.
I'll say your nom de plume is appropriate. There are two ways to reconcile these positions logically. One is that it is not the same Slashdotters making both claims (we have diversity of opinion here, in case you failed to notice). The other way is that the "competition" the first claim refers to is between corporations, not between formats. The former fuels markets, the latter fragments them. It's true that the latter is a consequence of the former, but it is not an inevitable consequence. For instance, nearly all books published in English today have the binding on the left side, even though there are many publishers competing for your cash.
The AC has nailed it. This is exactly the problem with DRM. Normally we have courts to judge whether a law is violated in any given case. If a human judge, at some future date, decides that a particular instance of copying is legal after all, then any DRM that blocks that form of copying (because some corporation decides today that such instances should be illegal) will render that judge's decision moot. And substituting corporate judgment for that of our legal system (however flawed the latter may be) is bad for the rule of law.
the polar bears survived then, they'll survive yet another.
Fact-checking time.
The polar bear did not exist as a separate species from the brown bear until 200,000 years ago.
The current ice age began 40 million years ago and is still going. The interglacial periods experienced during this ice age only mean that the ice sheets retreated to polar regions, instead of covering most of North America, Europe, and Asia.
So technically, no polar bear has ever survived the end of an ice age.
At cruising speeds (that's what we were talking about, right?), the regenerative braking benefit is negligible, so the 37% efficiency can be compared directly to the low-30% range efficiency of other ICEs. Overall hybrid efficiency is much higher (around 50%) and that would only go further to support my case, but it doesn't apply here.
In summary: weight of the hybrid system has no appreciable impact on mileage at cruising speeds, and there is a benefit from increased ICE efficiency under those conditions. Weight of the hybrid system has an impact on mileage at non-constant speeds, and that is far outweighed by the benefit of the hybrid efficiency.
What, exactly, do you expect? There is absolutely no way to show hard data on this because you can't do a head-to-head comparison between equivalent hybrid and conventional powered vehicles. All you offered was a potential way that hybrids could benefit at highway speed. I offered a potential reason why the hybrids would have an additional disadvantage at highway speed. You complain that disadvantage is minimal--I believe that your advantage is minimal. Go ahead and "show" me that you're right in whatever way you think is appropriate. Until you do, don't complain that I'm not "showing" anything.
As I recall, it was you who made the initial blanket statement, that hybrids offer no advantage in highway cruising. I think you have the burden of proof here.
Even in the case of a hybrid you have no idea what part of the benefit is from the hybrid engine as opposed to all the other improvements that toyota and honda put into the same cars.
Actually, I do. The efficiency of the Prius engine, a variation on the Atkinson cycle, is known to be about 37 percent (with not much variation over a fairly wide range of loads). Other engines with the traditional Otto cycle have peak efficiencies of around 30 to 33 percent.
Sorry, I meant I4, of course...Too much thinking for what's supposed to be a day off for me.
The funny thing is, my responses were only directed at your "pretty damn slow" remark. That remark perpetuates a myth, so my only interest was in correcting that myth. If you want to compare the hybrid 4- and non-hybrid 6- cylinder cars because they are similarly priced then, from a purchasing decision standpoint, that is perfectly fine, but that is a change of subject. It is still a useless data point for deciding whether hybrids are "pretty damn slow". Fact is, you take a baseline 4-cylinder and replace the engine with a V6, and it gets faster, but fuel consumption goes up, too. Take that same baseline car and put in a hybrid drive, and fuel consumption goes down. But wait -- this version is also faster than the baseline!
The actual deltas in price involved are irrelevant to the physics.
The key in comparing the 7.7 second and 8.6 second numbers is that they presumably came from the same source -- I would doubt that C&D would use different sources of information in reviewing these two cars. Occam's razor. If they are distorted, they are probably distorted more or less equally.
Finally, the 8.9 seconds in the article you quoted seems to belie your contention that the 7.7-second number came from Toyota.
You still have to cart the weight around, and that costs energy. Even at a constant speed you've got to push the weight up hills (acceleration against gravity) and you're going to pay more in rolling resistance (which also means you're not going to recover your energy when going back down the hill).
Energy to overcome gravity is largely repaid on the descent: you can travel the same distance coming down while using almost no gasoline, effectively doubling the MPG seen during the climb, and regenerative braking puts energy into the battery. The net energy loss compared to flat driving is small unless you are talking really steep grades, and since the hybrid adds about 10% weight, you are talking about 10% of an already small number. Most Prius drivers I've discussed with don't see any difference between hilly terrain and flat, and at least one that I know of claims to get better mileage on hills (not sure I believe him on that). Rolling resistance is only a small component of energy consumption at highway speeds, because it doesn't increase quadratically like drag does.
Sure I did--for some reason you just seem to believe that weight is free in terms of energy costs, which is false.
I never said weight is free in terms of energy costs; you are setting up a straw man. But, I repeat, you did not show how hybrids do not have any efficiency benefits in highway driving.
True that the weight matters when under acceleration, but its negative effect is more than outweighed by the overall efficiency increase which occurs under all conditions.
That really depends on how you drive, doesn't it? I drive about 70 miles per day, almost all of which is over 60MPH. (I'm off of divided highway for about a mile each way.) I guess I just don't count as "all conditions"? There are a lot of people in this country that are long-distance highway drivers, and hybrids really just aren't the right vehicle for them at this time. (Maybe when the costs come down a lot and the technology matures things will be different.)
Hmm, those conditions you describe don't seem to involve much acceleration, so any weight penalty for you would be negligible. Whereas, the higher efficiency of the smaller engine (the advantage I pointed out) could benefit you. Note that I have made no statement whatsoever about whether it would be cost effective.
It's getting a whole lot more common. Someone who has so much to say about how hybrids are a superior technology
Again a straw man, since I never stated that. I am only pointing out an advantage in hybrid technology that you overlooked (and now seem bent on denying). But I never said there were no other technologies offering useful advantages.
should really know more about what technologies are available, no?
Actually I am familiar with all the technologies you mentioned. I've driven a turbocharged car (Mazda) -- and loved it. I'm aware that some manufacturers are offering variable cylinder management these days but it isn't quite mainstream yet. I only said that I don't have any hard data on how much mileage benefit these technologies offer. Do you?
If getting more on-demand acceleration out of a smaller engine is all the hybrid's got going for it for highway driving, there are cheaper and easier ways (including those that I've already mentioned) to get the same thing.
The rub is, not all driving is highway. So a technology that has benefits under city driving conditions as well as highway conditions is well-suited to someone (like me) who drives mostly under the former. Granted that the frequent highway driver will probably do better in purely economic terms driving a TDI or a car with VCM, due to the lower initial investment.
Ah, I missed your statement on deriving the mileages because I was focusing on the Camry part of your response. I assumed you were using city miles because the numbers for both were low, but the numbers for the non-hybrids were higher than the current EPA so I was confused. At any rate, more than 80% of my driving is city and those are the numbers I tend to focus on, so from my personal standpoint it is a comparison (after '08 adjustment) between 21 MPG on one hand and a range from 28 to 32 MPG on the other, for me a significant difference. Still, until the EPA actually publishes test results using the new method, I would not trust the application of these scaling factors to one specific car.
Most sites that dont actually test the cars themselves will use the car manufacturer's numbers. And as we see with mileage claims, car manufacturers rarely tell the truth.
Whoa, there. Since when do manufacturers not tell the truth about mileage? They don't "make claims"; they simply publish the EPA results, as required by law. But I'm not aware of Toyota ever publishing specific acceleration test results for any of their Camrys (and a search of their website didn't turn up any). So I don't know where those numbers came from. I can only assume that the 7.7 s for Camry Hybrid and the 8.6 seconds for the Camry 4-cylinder SE (both cited in Car and Driver's reviews) came from the same source. It certainly would follow the expectation given ~20% higher power (and much higher torque at low RPM) vs. a 10% weight increase. And as I pointed out, testing with the battery depleted would remove these advantages, but in real life the only time the battery would be sufficiently depleted to see such an effect would be after a long mountain climb or maybe after driving into a strong headwind for a long time.
And sorry, but comparing a V4 hybrid to a V6 non-hybrid is not relevant when you are trying to show that hybrids "are pretty damn slow" (your original post). If you want to make a more general statement that "V4s are pretty damn slow" then by all means you should compare V4s to V6s and V8s and any other configuration you like. But a hybrid V4 should outperform a standard V4 with comparable MPG, and a hybrid V6 should outperform a standard V6 with comparable MPG.
The counter to that is that you're carting around the extra weight of the batteries and electric drive system all the time to no positive effect while cruising at highway speed.
How is that a counter? The weight has no negative effect on cruising MPG (the topic of this thread). Remember I originally was responding to your statement that "At highway speeds there aren't any inherent efficiencies to hybrid engines", and you still haven't offered any support to that assertion. True that the weight matters when under acceleration, but its negative effect is more than outweighed by the overall efficiency increase which occurs under all conditions.
Also, you can get similar efficiencies by either turbocharging or with variable cylinder management (turning off some cylinders, as at least some hondas and corvettes do).
Perhaps. Few models employ those techniques, and I don't know how well they compare with hybrid technology.
Slashdot Mirror
Two half-adders (plus an OR gate to combine carries) make a full adder, but a "full adder" and a "full computer" are two completely different things. You can put together a bunch of full adders to make a multi-bit adder. Add more logic to perform subtractions, shifts, plus logical and, or, and not operations, and you've got a nice little ALU. Now add some registers, a control store, instruction decoding logic, and a sequencer (complete with conditional branching logic), and you've got a CPU. And to build a computer, add memory and some kind of I/O.
I'd call that a good bit more than twice as many dominos.
Relax. You can always "correct" the Wikipedia article instead...
...or someone who cracks the code and figures how to splice in a random frame, a la Tyler Durden in Fight Club.
For the answer, read this op-ed piece about why the current system is so screwed up, and what can be done about it. I don't think the column goes far enough, though; it gives all the reasons for going to a single-payer system but stops short of calling for one.
You seem confident that the universe is deterministic.
That kind of argument is moot anyway. The original poster quoted Poe regarding "human ingenuity", not some hypothetical omniscience.
I also liked Liza Richardson, a KCRW (Santa Monica, CA) DJ.
Your story also illustrates why we need historians. Unfortunately they are usually ignored anyway...
Amen. Classic rock is a dumbing-down of AOR. AOR was a dumbing-down of the progressive format. Most of the non-classical part of my music collection (400 or so CDs, at a rough guess, and a couple hundred old LPs and tapes) could find play on either a progressive or AOR station, but much of it would never be found on today's radio. Genesis before Phil Collins took over? Pink Floyd pre-DSotM? The Nice? King Crimson? Soft Machine? Forget it!
I hope you're wrong about satellite radio because I'd like to try it out sometime.
In the early seventies there were progressive radio stations (mostly on FM) that would just play whatever the DJ liked, usually but not limited to progressive rock, and always out of the ordinary. Often they would play an entire side of an LP uninterrupted. Everything you heard was something you'd never hear on the AM top-40 stations. Sadly, this format was displaced by AOR stations playing automated playlists circa 1975, and later, classic rock stations playing Smoke on the Water and China Grove how many times per day. It's never been the same.
I'm sorry, but that's just a non sequitur. Regulating service providers is not the same as "controling the Internet". The latter would imply that the government monitors all Internet traffic and create and enforce its own policies regarding that traffic. Which, by definition, is another form of non-neutrality.
80 Gb/s would be the half-duplex bandwidth. Full duplex is 160 Gb/s (if you can find an application to utilize all of both directions). PCIe uses an encoding of 10 bits to the byte, for numerous technical reasons but primarily to maintain a DC balance (50% ones, 50% zeros) and to ensure maximum run lengths so that the clock (embedded in the serial stream) can be recovered at the receiving end. 160/10 = 16 GB/s.
The reason it's 16 (for full duplex) and not 20 is that 8b10b encoding requires 10 bits on the serial link to encode 1 byte of data.
Several people have answered this already, but I'll just add a few small points. Configuration space in PCI Express is a superset of PCI's configuration space. So a BIOS or OS that can talk to config registers on a PCI device can talk to config registers on a PCIe device. Also, the transaction layer mode (split transactions) is based on the PCI-X (not conventional PCI) model. You can think of the relationship between PCI and PCIe as similar to that between parallel SCSI and the serial interfaces that implement the SCSI command sets (SAS, iSCSI, and FC).
Gigatransfers/second. I think somebody on the committee thought Gigabits/second was underselling the bandwidth, since it only represents the bandwidth of one lane in a multilane link. So a "transfer" is the number of bits that can be moved simultaneously over all the lanes in a UI (unit interval, which is 0.2 ns at the new rate); consequently the size of a transfer will vary with the link width.
Sure, just like your Brangelinas, your Bennifers, and your Filliam H. Muffmans.
I'll say your nom de plume is appropriate. There are two ways to reconcile these positions logically. One is that it is not the same Slashdotters making both claims (we have diversity of opinion here, in case you failed to notice). The other way is that the "competition" the first claim refers to is between corporations, not between formats. The former fuels markets, the latter fragments them. It's true that the latter is a consequence of the former, but it is not an inevitable consequence. For instance, nearly all books published in English today have the binding on the left side, even though there are many publishers competing for your cash.
The AC has nailed it. This is exactly the problem with DRM. Normally we have courts to judge whether a law is violated in any given case. If a human judge, at some future date, decides that a particular instance of copying is legal after all, then any DRM that blocks that form of copying (because some corporation decides today that such instances should be illegal) will render that judge's decision moot. And substituting corporate judgment for that of our legal system (however flawed the latter may be) is bad for the rule of law.
You'll have won when you can debunk the substance of the argument, rather than just a sensational headline.
Fact-checking time.
The polar bear did not exist as a separate species from the brown bear until 200,000 years ago.
The current ice age began 40 million years ago and is still going. The interglacial periods experienced during this ice age only mean that the ice sheets retreated to polar regions, instead of covering most of North America, Europe, and Asia.
So technically, no polar bear has ever survived the end of an ice age.
In summary: weight of the hybrid system has no appreciable impact on mileage at cruising speeds, and there is a benefit from increased ICE efficiency under those conditions. Weight of the hybrid system has an impact on mileage at non-constant speeds, and that is far outweighed by the benefit of the hybrid efficiency.
As I recall, it was you who made the initial blanket statement, that hybrids offer no advantage in highway cruising. I think you have the burden of proof here.
Even in the case of a hybrid you have no idea what part of the benefit is from the hybrid engine as opposed to all the other improvements that toyota and honda put into the same cars.
Actually, I do. The efficiency of the Prius engine, a variation on the Atkinson cycle, is known to be about 37 percent (with not much variation over a fairly wide range of loads). Other engines with the traditional Otto cycle have peak efficiencies of around 30 to 33 percent.
The funny thing is, my responses were only directed at your "pretty damn slow" remark. That remark perpetuates a myth, so my only interest was in correcting that myth. If you want to compare the hybrid 4- and non-hybrid 6- cylinder cars because they are similarly priced then, from a purchasing decision standpoint, that is perfectly fine, but that is a change of subject. It is still a useless data point for deciding whether hybrids are "pretty damn slow". Fact is, you take a baseline 4-cylinder and replace the engine with a V6, and it gets faster, but fuel consumption goes up, too. Take that same baseline car and put in a hybrid drive, and fuel consumption goes down. But wait -- this version is also faster than the baseline!
The actual deltas in price involved are irrelevant to the physics.
The key in comparing the 7.7 second and 8.6 second numbers is that they presumably came from the same source -- I would doubt that C&D would use different sources of information in reviewing these two cars. Occam's razor. If they are distorted, they are probably distorted more or less equally.
Finally, the 8.9 seconds in the article you quoted seems to belie your contention that the 7.7-second number came from Toyota.
Energy to overcome gravity is largely repaid on the descent: you can travel the same distance coming down while using almost no gasoline, effectively doubling the MPG seen during the climb, and regenerative braking puts energy into the battery. The net energy loss compared to flat driving is small unless you are talking really steep grades, and since the hybrid adds about 10% weight, you are talking about 10% of an already small number. Most Prius drivers I've discussed with don't see any difference between hilly terrain and flat, and at least one that I know of claims to get better mileage on hills (not sure I believe him on that). Rolling resistance is only a small component of energy consumption at highway speeds, because it doesn't increase quadratically like drag does.
Sure I did--for some reason you just seem to believe that weight is free in terms of energy costs, which is false.
I never said weight is free in terms of energy costs; you are setting up a straw man. But, I repeat, you did not show how hybrids do not have any efficiency benefits in highway driving.
True that the weight matters when under acceleration, but its negative effect is more than outweighed by the overall efficiency increase which occurs under all conditions.
That really depends on how you drive, doesn't it? I drive about 70 miles per day, almost all of which is over 60MPH. (I'm off of divided highway for about a mile each way.) I guess I just don't count as "all conditions"? There are a lot of people in this country that are long-distance highway drivers, and hybrids really just aren't the right vehicle for them at this time. (Maybe when the costs come down a lot and the technology matures things will be different.)
Hmm, those conditions you describe don't seem to involve much acceleration, so any weight penalty for you would be negligible. Whereas, the higher efficiency of the smaller engine (the advantage I pointed out) could benefit you. Note that I have made no statement whatsoever about whether it would be cost effective.
It's getting a whole lot more common. Someone who has so much to say about how hybrids are a superior technology
Again a straw man, since I never stated that. I am only pointing out an advantage in hybrid technology that you overlooked (and now seem bent on denying). But I never said there were no other technologies offering useful advantages.
should really know more about what technologies are available, no?
Actually I am familiar with all the technologies you mentioned. I've driven a turbocharged car (Mazda) -- and loved it. I'm aware that some manufacturers are offering variable cylinder management these days but it isn't quite mainstream yet. I only said that I don't have any hard data on how much mileage benefit these technologies offer. Do you?
If getting more on-demand acceleration out of a smaller engine is all the hybrid's got going for it for highway driving, there are cheaper and easier ways (including those that I've already mentioned) to get the same thing.
The rub is, not all driving is highway. So a technology that has benefits under city driving conditions as well as highway conditions is well-suited to someone (like me) who drives mostly under the former. Granted that the frequent highway driver will probably do better in purely economic terms driving a TDI or a car with VCM, due to the lower initial investment.
Most sites that dont actually test the cars themselves will use the car manufacturer's numbers. And as we see with mileage claims, car manufacturers rarely tell the truth.
Whoa, there. Since when do manufacturers not tell the truth about mileage? They don't "make claims"; they simply publish the EPA results, as required by law. But I'm not aware of Toyota ever publishing specific acceleration test results for any of their Camrys (and a search of their website didn't turn up any). So I don't know where those numbers came from. I can only assume that the 7.7 s for Camry Hybrid and the 8.6 seconds for the Camry 4-cylinder SE (both cited in Car and Driver's reviews) came from the same source. It certainly would follow the expectation given ~20% higher power (and much higher torque at low RPM) vs. a 10% weight increase. And as I pointed out, testing with the battery depleted would remove these advantages, but in real life the only time the battery would be sufficiently depleted to see such an effect would be after a long mountain climb or maybe after driving into a strong headwind for a long time.
And sorry, but comparing a V4 hybrid to a V6 non-hybrid is not relevant when you are trying to show that hybrids "are pretty damn slow" (your original post). If you want to make a more general statement that "V4s are pretty damn slow" then by all means you should compare V4s to V6s and V8s and any other configuration you like. But a hybrid V4 should outperform a standard V4 with comparable MPG, and a hybrid V6 should outperform a standard V6 with comparable MPG.
How is that a counter? The weight has no negative effect on cruising MPG (the topic of this thread). Remember I originally was responding to your statement that "At highway speeds there aren't any inherent efficiencies to hybrid engines", and you still haven't offered any support to that assertion. True that the weight matters when under acceleration, but its negative effect is more than outweighed by the overall efficiency increase which occurs under all conditions.
Also, you can get similar efficiencies by either turbocharging or with variable cylinder management (turning off some cylinders, as at least some hondas and corvettes do).
Perhaps. Few models employ those techniques, and I don't know how well they compare with hybrid technology.