Chuckle at the "made by aliens" silliness as we all do, there really is a mystery to this device. Archimedes was more than brilliant enough to work out the math for this orrery, also to work out the design for gear tooth profiles. He had the position and influence to have access to materials and the best crafts-people of the time. But how did they actually build that thing? In theory an astonishingly good watchmaker could hand-file all those gears. In practice, I'm not so sure. Gears are finicky things, every single tooth must have the correct angular position, pitch diamerter and involute profile. A gear can look very pretty but simply not work with another gear. (I have made several such.) If you don't believe it, just go to a hardware store, buy a riffler file kit and some brass washers, then have at it. No microscope, no computer, no plotter. Any tools you hypothesize have to be built using the same starting conditions. It will be an educational experience. One of your observations will be that you can not see well enough to get the profile to adequately match the math for two gears to mesh smoothly. So the greatest mystery, for me, is: How did they make the measurements required for this work?
During the early days of the car, I was part of an engineering group asked by DMC to suggest improvements. We were all astonished at the plumbing and wiring mess and the company engineers confirmed it was the major contributor to reliability problems. Manufacturing cost too. Under the pretty SS skin it is very 1960's Chevy|Ford.
( I suggested using a microcontroller-based serial communication bus for all control signals, primarily to relieve the mess behind the dash. The 'car guys' of the day said that would never happen. 8^)
The separate department structure for computer systems encourages everyone to take the approach of 'Not My Problem' even when they could fix it. From a broader perspective, the barriers among Dev/QA/Ops are artificial: it is all computer people doing computer-ish stuff. External constraints are vastly simpler than the construction analogy -- no opcode shipments stuck in Customs, no delays from rain or freezing temperatures. If the computer industry can not overcome these lesser barriers there is little hope of handling bigger barriers such as Marketing|Development.
And they really need to be overcome. Industry has spent a truly astonishing amount of money on 'computer systems' with frequently negative results. Recall the number of anecdotal reports of large computer system efforts that are abandoned after YEARS of work for many millions of dollars. Although the computer system company has a 'loss' of anticipated future revenue from the project, the host company loses real money and irreplaceable time. Further, they are often left with a confused and discouraged work force that will affect them for years to come.
No, now they recharge batteries during the day. Remember that each disposable battery they deplete is at the end of an extremely long and dangerous supply tail. Remember also that each unit of fuel to run generators is brought by the same long tail, plus it is in a fuel tank truck -- aka 'Juicy Target'. Several years ago the military realized they needed a better option. These reports of new systems are the results from multiple efforts to make devices that suit the military environment and needs.
... simply walk to the nearest library and check out a paper manual?
I really don't know whether to suspect a marketing type or a software-only technical person. Either way, certainly someone who never actually works on cars!
Once upon a time I briefly but seriously considered selling "special digital audiophile cables". They would be advertised as eliminating the "metallic twang" of low-rent copper cables by using an all-natural electrolytic fluid that I would produce myself. This plan had the additional benefit of writing-off beer as raw materials, a business expense. Wonder if Chimay results in a more sophisticated sound than PBR?
Google for "Functional Muscle Stimulation" research over the last 3 decades. Some recent big milestones too. I visited one researcher and saw the neat rows and columns of circular scars where he had taken core samples of his own muscles during experiments. n > 100. That is dedication.
If you really must use PVC, at least use schedule 80 pipe. The stuff commonly available in hardware stores is schedule 40, intended for use in unpressurized drains only.
Everyone who is trying to apply Nyquist to a music signal is missing the.. signal in the noise of this thread.
Communications doesn't care about the shape of the waveform, only the frequency. Nyquist gives the absolute minimum sampling rate required to identify the signal frequency and it assumes there are no higher frequencies present in the signal (hence anti-aliasing filters).
I Am Not an Audiophile, but in past data acquisition work I used 10 samples per cycle as a rule-of-thumb to adequately capture the shape of the wave. That criteria happens to fit well with the 192KHz rate, as shown by the parent post.
I do agree withe the comments about 32-bit D/A - that is just silly.
The legal mafi err... I mean profession... realized they can increase billable hours by orders of magnitude if the schedule stretches. Don't expect it to get better. (In all fairness, some unscrupulous software developers use the same stunt.)
Re:No difference for a long while, but...
on
The End of the Oil Age
·
· Score: 2, Informative
Depends on how the H2 is stored. If pressurized gas, it would rise and dissipate (if ignited would rise more quickly but would make a calm blue light in the sky for a while). If locked in a hydride or borax, would lie there until shop-vac'ed up. Now, how would gasoline act? That is being trucked around everywhere daily.
Bought an album from them and couldn't burn it even once. Their Customer Dis-service basically said that was my problem. So I can listen to it on my scritchy little PC speakers but not my (modest) audiophile-type system. In my opinion they took my money and delivered nothing, they are aware of that, and are quite happy with that outcome.
"Bluetooth is Dead" == "IrDA is Dead"
on
Is Bluetooth Dead?
·
· Score: 1
For those of us old enough to remember: the frantic marketing pronouncements for Bluetooth were identical to the earlier foolish claims for IrDA. It would take over the world, change diapers, walk the dog. Well, it didn't/won't but it did/will quietly become a common and decently effective way to link two devices without wires. These snake-oil claims will subside only when the venture capitalists learn that a true incremental advance can create more value than a revolutionary lie.
Definition and assumption of "acceptable risk" is another critical aspect of the adoption process. Our society, and very specifically our legal structure, have built definitions of tolerance for the risks of storing and transporting gasoline that would *never* be accepted if it were a new thing.
Once, long ago, I was involved in a study of using metal hydrides for storing hydrogen (kind of like a magic sponge - H2 tank only slightly larger than a gasoline tank for the same range). The problem was that it needed to be hot - maybe 100C I can't remember - to give up the stored hydrogen; if a crash ruptured the tank this moderately hot stuff might spill out. Since there was no industry/social practice to define a limit on the legal liability of this event, the risk killed the technology even though a ruptured gasoline tank is a drastically worse event.
This legal inertia is a serious impediment to many technical improvements. None of us need to be reminded how litigation-happy the US has become and the staggering sizes of product liability awards despite incredibly bone-headed user moves.
It was particularly good in the context of the edit-compile-link-debug(at machine level!) status quo. Integrated environment running on a single floppy disk - remember that 10M hard drives were still gleams in eyes for most of us. Very fast on a 640k 8088.
TP1 was a major innovation in the practice of coding, but probably would have had more respect if Borland charged 10x the $49.95 price. No tool change since has made the same kind of step difference to me personally.
Slashdot Mirror
Chuckle at the "made by aliens" silliness as we all do, there really is a mystery to this device.
Archimedes was more than brilliant enough to work out the math for this orrery, also to work out the design for gear tooth profiles. He had the position and influence to have access to materials and the best crafts-people of the time. But how did they actually build that thing?
In theory an astonishingly good watchmaker could hand-file all those gears. In practice, I'm not so sure. Gears are finicky things, every single tooth must have the correct angular position, pitch diamerter and involute profile. A gear can look very pretty but simply not work with another gear. (I have made several such.) If you don't believe it, just go to a hardware store, buy a riffler file kit and some brass washers, then have at it. No microscope, no computer, no plotter. Any tools you hypothesize have to be built using the same starting conditions. It will be an educational experience. One of your observations will be that you can not see well enough to get the profile to adequately match the math for two gears to mesh smoothly.
So the greatest mystery, for me, is: How did they make the measurements required for this work?
During the early days of the car, I was part of an engineering group asked by DMC to suggest improvements. We were all astonished at the plumbing and wiring mess and the company engineers confirmed it was the major contributor to reliability problems. Manufacturing cost too. Under the pretty SS skin it is very 1960's Chevy|Ford.
( I suggested using a microcontroller-based serial communication bus for all control signals, primarily to relieve the mess behind the dash. The 'car guys' of the day said that would never happen. 8^)
Wish I had mod points handy.
The separate department structure for computer systems encourages everyone to take the approach of 'Not My Problem' even when they could fix it. From a broader perspective, the barriers among Dev/QA/Ops are artificial: it is all computer people doing computer-ish stuff. External constraints are vastly simpler than the construction analogy -- no opcode shipments stuck in Customs, no delays from rain or freezing temperatures. If the computer industry can not overcome these lesser barriers there is little hope of handling bigger barriers such as Marketing|Development.
And they really need to be overcome. Industry has spent a truly astonishing amount of money on 'computer systems' with frequently negative results. Recall the number of anecdotal reports of large computer system efforts that are abandoned after YEARS of work for many millions of dollars. Although the computer system company has a 'loss' of anticipated future revenue from the project, the host company loses real money and irreplaceable time. Further, they are often left with a confused and discouraged work force that will affect them for years to come.
Everyone knows it: Knuth's "The Art of Computer Programming"
Now get off my lawn!
No, now they recharge batteries during the day. Remember that each disposable battery they deplete is at the end of an extremely long and dangerous supply tail. Remember also that each unit of fuel to run generators is brought by the same long tail, plus it is in a fuel tank truck -- aka 'Juicy Target'.
Several years ago the military realized they needed a better option. These reports of new systems are the results from multiple efforts to make devices that suit the military environment and needs.
... simply walk to the nearest library and check out a paper manual?
I really don't know whether to suspect a marketing type or a software-only technical person.
Either way, certainly someone who never actually works on cars!
Once upon a time I briefly but seriously considered selling "special digital audiophile cables". They would be advertised as eliminating the "metallic twang" of low-rent copper cables by using an all-natural electrolytic fluid that I would produce myself. This plan had the additional benefit of writing-off beer as raw materials, a business expense. Wonder if Chimay results in a more sophisticated sound than PBR?
Google for "Functional Muscle Stimulation" research over the last 3 decades. Some recent big milestones too.
I visited one researcher and saw the neat rows and columns of circular scars where he had taken core samples of
his own muscles during experiments. n > 100. That is dedication.
If you really must use PVC, at least use schedule 80 pipe. The stuff commonly available in hardware stores is schedule 40, intended for use in unpressurized drains only.
Communications doesn't care about the shape of the waveform, only the frequency. Nyquist gives the absolute minimum sampling rate required to identify the signal frequency and it assumes there are no higher frequencies present in the signal (hence anti-aliasing filters).
I Am Not an Audiophile, but in past data acquisition work I used 10 samples per cycle as a rule-of-thumb to adequately capture the shape of the wave. That criteria happens to fit well with the 192KHz rate, as shown by the parent post.
I do agree withe the comments about 32-bit D/A - that is just silly.
The legal mafi err ... I mean profession ... realized they can increase billable hours by orders of magnitude if the schedule stretches. Don't expect it to get better. (In all fairness, some unscrupulous software developers use the same stunt.)
It certainly did the trick for me!
Fine camera, well established lens and accessory lineup, and they already have a digital body if/when you want to switch.
sorry, the voice in the coffeepot made me say it.
Depends on how the H2 is stored. If pressurized gas, it would rise and dissipate (if ignited would rise more quickly but would make a calm blue light in the sky for a while). If locked in a hydride or borax, would lie there until shop-vac'ed up. Now, how would gasoline act? That is being trucked around everywhere daily.
Bought an album from them and couldn't burn it even once. Their Customer Dis-service basically said that was my problem. So I can listen to it on my scritchy little PC speakers but not my (modest) audiophile-type system. In my opinion they took my money and delivered nothing, they are aware of that, and are quite happy with that outcome.
For those of us old enough to remember: the frantic marketing pronouncements for Bluetooth were identical to the earlier foolish claims for IrDA. It would take over the world, change diapers, walk the dog. Well, it didn't/won't but it did/will quietly become a common and decently effective way to link two devices without wires. These snake-oil claims will subside only when the venture capitalists learn that a true incremental advance can create more value than a revolutionary lie.
We may have already created the "next" NSI.
Once, long ago, I was involved in a study of using metal hydrides for storing hydrogen (kind of like a magic sponge - H2 tank only slightly larger than a gasoline tank for the same range). The problem was that it needed to be hot - maybe 100C I can't remember - to give up the stored hydrogen; if a crash ruptured the tank this moderately hot stuff might spill out. Since there was no industry/social practice to define a limit on the legal liability of this event, the risk killed the technology even though a ruptured gasoline tank is a drastically worse event.
This legal inertia is a serious impediment to many technical improvements. None of us need to be reminded how litigation-happy the US has become and the staggering sizes of product liability awards despite incredibly bone-headed user moves.
It was particularly good in the context of the edit-compile-link-debug(at machine level!) status quo. Integrated environment running on a single floppy disk - remember that 10M hard drives were still gleams in eyes for most of us. Very fast on a 640k 8088.
TP1 was a major innovation in the practice of coding, but probably would have had more respect if Borland charged 10x the $49.95 price. No tool change since has made the same kind of step difference to me personally.