Unless I'm mis-interpreting what you've said, I completely disagree with your notion that math and physics are easier to learn without bringing in oranges and apples. This has been the case with my experiences throughout my education. First example is calculus. I was always pretty good in math until I studied high school AP calculus. IMHO, my teacher just sucked balls, almost like he didn't intuitively understand the subject. We were routinely applying methods of integration, by following textbook rules, WITHOUT any inherent understanding of what the hell dx really means, or why the chain rule applies. The only two math topics I didn't understand in high school were matricies and calculus, and this is, I believe, due to the inability of the teacher to explain what was fundamentally occurring. Sure, matrix multiplication follows a set of defined rules for element multiplcation and addition, but there was no explanation of why we do that, or what it's trying to accomplish. This is akin to my fifth-grade teachers that gave us homework after homework of multiplying 4 digit numbers by 4 digit numbers. Okay, after doing a few 2x2 numbers, or an occasional 4x4 you can learn the methods, but this was ridiculous. We weren't learning, we were being trained as monkeys to follow through a multiplication algorithm, without even understanding what multiplication implies, or why we were applying our cookbook methods. For instance, "why do we shift in an extra 0 at the units digit when we multiply by the 10's digit?". Did the teachers even understand this? This is why I strongly believe in word problems, which reveal why math operations are occuring, and how you'd use them. Physics is the word problems of calculus. When i went to college and majored in physics, that's when calculus finally made sense. "Oh, I see. We want to sum the work this particle does as it moves across this nonlinear force field, so I'll sum a set of infinitesmal forces, dF, at each infinitesmal point dx in space. Hey, when I write out the summation equation, that's an integral. Gee, now I understand what the hell I was doing in high school." I knew what the upper-case SIGMA meant in math, sum an integer set of discrete numbers. If only my teacher said an integral was exactly the same thing, but occuring through all points, not just discrete integers, it would have made sense. But I had to wait until college physics for that. There are many other calculus examples. For instance, one set of problems we did in high school was spin a curve about an axis, and determine the surface area of the resulting solid. we would just "plug and chug" the curve into the magic formula for surface area, and we get the answer. "Where does this formula come from? What does it mean?" If only my teacher said that what we're really doing is breaking the object into a set of small cylinders, and summing the surface area on each of these, I could have understood. Relevant examples also exist in more advanced topics. Vector calculus doesn't really mean much at all on it's own. What is a Gradient, Divergence,or Curl really? Okay, I can figure out what the curl of a vector field is, but what is the significance? And what is the point of Stoke's and Green's theorems? Again, these made sense once I needed to apply these to physics, which provided the word-problem analogy to these concepts. The fundamentals of matrices made sense once I got to quantum mechanics, and now I can see how they apply to all sorts of algebraic systems. In an applied math class I took later, on the first day the prof related an algebraic system to solve to an electronic network. The implications of matrices suddenly made perfect sense, and the light bulb in my mind just suddenly switched on. I believe this wouldn't have happened if the theory was not applied to a real system for understanding. You write: integrating is something people just don't tend to do, on a day-to-day basis. Yes, but you don't need to do something every day in order to present a concrete example to make an idea easier to understand. Just my $0.02, though.
It's really interesting, because this has been said for the last 7 years. Every new season, the old hardcore veterans talk about old shows, and how the new ones just don't compare. Then after these veterans see the episode 2 or 3 times and catch all the little witty pieces, it grows on them, and they move on to the next newest episode to grip about.
Don't get me wrong, there definitely are really boring and unfunny Simpsons episodes, but throughout each season there are certain episodes and moments of pure hysteria.
On an unrelated note, has anyone seen 'The Critic'? Now that's a show that has been unjustly cancelled twice, but when it's on a roll, it's really on a roll! Cartoon Network has reruns of it sometimes, but there's only like 15 or so episodes. If given a longer chance, I think it could have become totally awesome. [Note, some episodes of it are painfully cheesy, but the parts that are funny are enough to give your diaphragm a year's worth of exercise). IMHO, of course.
I know it seems kind of ugly, but MSFT may have had the right idea in terms of numbering software packages similar to automobiles (ie, win95, win98, etc). This way, you know when a package came out, and entities aren't one-upping each other to be at the highest number. (well, they may jump ahead to the next year, but that's mostly irrevelent).
How do the rest of you guys feel about the year numbering scheme. Minor versions could be like MyLinux 2000.0, and MyLinux 2000.1, or similar. Maybe even something akin to the WINE packages.
Are there other schemes that may be better than just Mandrake 7.x or Mandrake 2000?
I've used RedHat 5.2 and 6.0, and Mandrake 6.0 and 6.1. The way Mandrake was introduced to me, which seemed correct, was like RedHat, but with the bugs fixed and extra goodies included.
If you want support or help, try the mailing lists, they're really informative! One of their techies, Axalon Bloodstone, slaves away to answer multitudes of questions posed by newbies and experts alike. Find the link from their site
But Mandrake, AFAIK (I'm currently using Mandrake 6.1) WAS based on RedHat's distribution. They've since branched out, and are now they're own independent derivative branch, with their own modifications and way of doing things (ie, their different installers and configuration tools).
On a different note, I also prefer Mandrake, but what sometimes ticks me off is the Pentium compile optimizations, as I must hack things, or use a differnt distro, for 486 machines.
You hate to see a better product succeed just because of your political agenda? Pretty sad if you ask me.
You're view of only 'the product' is far more sad, if you ask me.
Would you buy a pair of "better" sneakers if you knew that NIKE was using cheap child labor in a third-world country to build them? Would you buy "better" lumber if you knew it was old-growth wood from the rain forest? If you were alive 200 years ago, would you buy Plantation cotton from the American south, which was harvested by slaves, or maybe buy slightly less-quality cotton grown by free workers?
The political agenda behind the product often matters, as you can see. If we aren't willing to stand up for what we believe in, we may as well not be human. Try taking a stand for once, and follow what you believe in. You may feel pretty good about it.
"In a world without walls, who needs Windows" - Someone from LinuxToday
This reminds me of a story I've heard a few years ago about some man that insured 24 expensive cigars against fire. Somehow, the insurance company let that one slip.
So, he smoked them all, then called the insurance company and reported the loss of his cigars due to a series of small fires. They wouldn't pay up, so he took them to court. In court, he admitted smoking the cigars, and won because the court stated the contract was worded to protect the cigars against fire.
However, the scales of justice wouldn't remain tipped. The insurance company then filed charges against him on 24 accounts of arson. He was found guilty, using his evidence related in the previous case where he collected the insurance money. Ultimately I think he was thrown in jail.
That's a good example of the system working to punish those that would otherwise take advantage of it.
"In a world without walls, who needs Windows" - Someone from LinuxToday
Good idea, but have fun building a demultiplexer that will provide 144 dB of isolation between each sample (such that a sample won't "leak" into the next AD) and also maintaining that 144 dB of linearity integrity of the original signal.
"In a world without walls, who needs Windows" - Someone from LinuxToday
Now, it is VERY difficult to get 144 dB of dynamic range, and even harder to achieve that level of linearity (measured by total harmonic distortion, THD). 144 dB is a ratio of 20,000,000:1. It is EXTREMELY difficult to build circuits that have this level of performance. I'm not even sure if and sampled data systems have achieved 24 bit performance.
I just want to chime in here. It isn't just the fact that we're aiming for 24 bits (ie, 144 dB) SNR here, but it's also the sampling rate that matters with respect to difficulty. It's a general trade off with analog-digital converters (as well as most circuit systems in general) between accuracy and speed. There are a number of 24-bit ADC's that work quite well, I believe. They use dual-slope current ramping (amongst other methods) to really get an accurate level of the voltage to be sampled. HOWEVER, and it's a big however, these things are slower than molasses.
A quick stroll by the Analog Devices website shows a bunch of 24-bit AD converters which I'm sure are up to specification. However, none samples higher than about 1 kHz. Maybe somewhere else in their page are other converters, but this is a rough indication of what's available today. The faster you go, the more you sacrifice SNR. So, to be repetitive just one more time, it's not the 24 bits that hurts you, but the combination of 24 bits at 96 kHz which makes it hard.
"In a world without walls, who needs Windows" - Someone from LinuxToday
It's not about the technology. It's about the music. I, personally, can "listen" to a piece of music by looking at the notes on the printed sheet music (hackers would call it "the source code") and playing the notes in my head.
So, then, acoustics would mean nothing to you. Why bother with the expense of a stradivarious as opposed to a cheesy keyboard emulating a violin. It's all just the same notes anyway.:-)
I'll really be in awe when you just look at a CD, and can appreciate the tunes on it. Or even a record, for that matter.:-)
"In a world without walls, who needs Windows" - Someone from LinuxToday
I think 24-bit audio is overkill, but it'll set the stage for the next (probably) many decades. 16-bit audio may have extremely small perceivable digitization effects, but 18-bit audio should eliminatate most of these. I would also think that on a 24-bit SNR 96-kHz sampler, the 5 or 6 most LSB's are probably random noise anyway.
As to the above post referring to frequencies above the range of hearing that refer to location, these can occur way into the MHz! I've been told (not personally witnessed, though), that if you take a channel of audio sound and play it into the right ear, and play an identical audio channel, only delayed 1 us, into the left ear, you can notice a very certain direction to the music. Change the delay, and you've changed the direction al response of the sound.
This is why very good audio amplifiers should have bandwidths up into the MHz, and not just rolled off at 20 kHz or so. CD-quality sound is pretty good, and can still produce these MHz-type effects, though it's been sampled at 44 kHz. How, you wonder? Well, it has to do with the 96 dB (16 bit) SNR. Phasing of a sine-wave can be determined rather precisely with the 96 dB of range, due to the 65536 distinct levels each voltage point can be. There's enough vertical resolution (amplitude) that horizontal spacing (phase) can be determined rather precisely.
Of course, moving beyond the 16-bit level of SNR is pointless, unless you've got the equipment to handle it. Ie, inherent non-linearities of the decoupling caps between amplifier stages is a killer. If your system is using a cheesy electrolytic here (the horrors), rip that puppy out and use a polystyrene cap. Eventually you may want to bypass this and DC couple all the stages. Also, use monster-cable to the speakers, even any small resistance from amp output to speakers will form a divider with the speaker cone, and introduce isolation from the output driver, which will distort your frequency response. Also never use a passive crossover, use an active one before your final amplifier. This doubles the needs of amplification, but hey, you're an audiophile, right? You'd be surprised by the supposed high-quality audio systems that still throw in a cheapo 50-cent cap just to save a few bucks. Ack!
"In a world without walls, who needs Windows" - Someone from LinuxToday
I don't fully understand the BSD license, but here's my question anyway. What is to prevent someone from taking the OpenBSD sources and making their own kludged changes, and releasing that as MyVeryOwnBSD?
Upwards on this thread it stated that one could make changes under the BSD license and release an executable without releasing the source code. Doesn't this imply that they can thus also produce MyVeryOwnBSD, placing themselves in the MyVeryOwnBSD governing elite in the process? (of course they had better be a damn good coder to justify it).
"In a world without walls, who needs Windows" - Someone from LinuxToday
A number of variations of this method have been bouncing around for years now. I used to participate in ICEPIC, which was a listserv setup to discuss various problems for such a mission and propose methods to overcome them. Most members were hobbyists/scientists just discussing this stuff in our free time, but there may have been some professional spacecraft designers that took part in the discussions, I'm not sure.
Lots of interesting problems and propositions appeared. For example, getting through the ice. Do you drill, or use an RTG. RTG seems like the best way to go, but you cannot just 'turn' the RTG 'off' once you're through the ice. Hope it doesn't mess up any discoveries that may await. If you 'drop' the RTG spike, as the poster suggested above, then you had better either have some other sort of power source on the hydrobot, or have your several km of tether to the surface craft (see below).
Another problem is power, but if you've got that RTG onboard, you may be cured of this. If not, then you must run a tether to some sort of power source (solar panels or similar) down a several km-long tether to power the hydrobot.
Also interesting is comm. If you run a tether, which is a royal pain in it's own way, you've got many channels of fiber to talk through. Otherwise, RF transmission through many km of ice and water is too difficult. Another possibility is using a sonar-based modem, but can this transmit from water through several km of ice, or does it reflect off the ice?
These just off the top of my head. Very tough problem, considering the huge initial expense (in terms of mass, power, and even money) to get to the reaches of Europa. Better have lots of reduncancy and other plans in case things don't work right (which of course, they won't).
"In a world without walls, who needs Windows" - Someone from LinuxToday
Though maybe not strictly desktop-related computer magazines, the following magazines are really amazing, and remind me of what Byte was 1-2 decades ago. Written by real tech hackers for other techies. These focus mostly on embedded systems, and this is what completely picqued my interested in embedded computing. If you're not sure what embedding computers are, or how cool they are, please do yourself a favor and check these sites out.
Note - I don't work for these mags, nor am I being paid by them, etc. I am promoting them merely because I think they're awesome.
Circuit Cellar Ink is an excellent magazine focusing on hardware and software interaction. Articles on embedded computers and software/firmware implementation, with real life examples of what techs in the business are doing. Current issue deals with making a MIDI sustain pedal, details of dual-slope analog-digital converters, Infrared Device technology and how to use it in your own projects, and other informational articles such as description of the current status of HDTV. One really awesome article that ran 1 or 2 months ago dealt with an engineer homebrewing his own microprocessor based on the Z-80 instruction set, but with little goodies thrown in. Way cool. Someone in an above thread mentioned they liked the ads in some good computer magazines. Same with this magazine, all sorts of embedded-related ads. Oh yeah, this mag is big on the PIC and Basic Stamp. If you don't know what these are, take a look!
Another good one is embedded systems programming . I haven't had the time to read the current issues in-depth, but I keep meaning to do so. Going through my father's collection back a few years, there are some majorly good articles here. This mag devotes itself, obviously, to embedded systems programming. Current issue deals with communication issues, real-time stuff, embedded web servers, etc. Another good thing is their tech columns, which deal with real-life examples of coding. They've had a series aimed at moving C coders (like me) to C++ through specific examples. Also mathematical applications, such as a multi-part indepth review of Z-transforms and Fourier Transforms, and DSP programming, and how to implement these in your systems. Way cool stuff, too, IMHO.
Just for browsing the net, an amazing source of info is from Don Lancaster's Lair . Rightly named the guru, this guy is a tech genuius (sp), and does all sorts of great stuff like working with PIC's inside and out, programming in raw Postscript to make his printer act as a peripheral computer, and other stuff. Go check out his page. Now! Engage.
"In a world without walls, who needs Windows" - Someone from LinuxToday
It would seem that a new company coming in like this would have a hard time forking the kernel suddenly. For example, if they had closed additions for the kernel, in this case Amiga interoperability and/or emulation programs, it seems that this wouldn't catch on too quicky. I would guess, from the wealth of open-source projects and advocacy, that either enough people would complain to the company to open their code and they'd eventually agree, or an open-source version of the software would be released. I would think they'd need to have people dependent on their closed-source software for a long enough time for enough of a dedicated consumer base to justify a kernel fork. IMHO, of course. [Note - sorry for the double post, I accidentally hit submit instead of preview, and I'm not sure if the post was truly submitted or not without a subject]
"In a world without walls, who needs Windows" - Someone from LinuxToday
Yeah, that part about NT really pisses me off (sorry, we use NT at work). I'm so used to hitting those three keys to login, logout, and even get to the task manager, it's such a bad habit to get into. I was recently on an old 486 in the lab collecting some data (ms-dos 6.22), and I rebooted the thing several times accidentally, just out of habit. Good thing my linux box at home ignores this combo when I'm running X.
"In a world without walls, who needs Windows" - Someone from LinuxToday
From the slashdot headlines of the last few months, most of us are pretty aware of many of the ridiculous (sp) being put forth to the US patent office. However, is this absurdity limited only to software patents?
For example, do people in the auto business patent the idea of a plate on the floorboard, that when depressed, through a clever system of force transfer, opens and closes the throttle valve? Or the use of hollowed-out rubber torii (toruses?) which will not only support an automobile, but when rotated, propel it forward.
I know about the strange genetic patents, but are computers and the human genome the only areas that seem to be exploited by these ridiculous patents?
vacuum has no mass - it isn't a medium that can carry energy.
Ummm, well how about the Voyager spacecraft travelling through space? They have mass, E=mc^2, so they thus have energy, and they surely appear to be 'carried' through this vacuum medium. Of course, one can claim that space isn't a pure vacuum but has a few hydrogen particles per cubic meter, but then again that is what light (and gravity) is travelling through from the sun anyway.
I think you may have meant to accord with the notion that space (vacuum) has no ether, thus the logical way of explaining energy being transferred through it is as a particle, because what can the E&M or gravity waves oscillate to carry them forward?
Sorry if I'm misinterpreting your point. It just strikes me as a not-well-understood notion (from my point of view, that is). I cannot wait to get to grad school and do E&M again (as well as GR and QM)...
Hahaha, thanks for the link, I got a real kick out of reading that article.
If he's so worried about us pesky humans playing God, why is he publishing on an online medium? I mean, weren't we playing god 100 years ago when Faraday and Maxwell were working out the basics of E&M, and Shockley/Bardeen/others again with solid state research to bring us the transistor, which directly leads to the computer on his desk.
In fact, metallargusts of antiquity were playing God as well, so we shouldn't use metals, lest we upset the delicate balance of the universe. Wait, he does denounce the combustion engine. I guess this implies he walks/bikes/etc wherever he goes, so as not to upset the ecosystem.
He seems to be the only clear-thinker among us, if it weren't for him I'm sure we'd all be up a paddle.
Everybody keeps mentioning the fact that a Tempest can scan the RF noise for 1000 yards to capture video signals. How does it distinguish between multiple monitors within this range? Ie, can it pick only one of many sync rates? or does some funky DSP filter out the other monitors? Or do other monitors distort the signal enough that it can act like a jammer?
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Unless I'm mis-interpreting what you've said, I completely disagree with your notion that math and physics are easier to learn without bringing in oranges and apples. This has been the case with my experiences throughout my education. First example is calculus. I was always pretty good in math until I studied high school AP calculus. IMHO, my teacher just sucked balls, almost like he didn't intuitively understand the subject. We were routinely applying methods of integration, by following textbook rules, WITHOUT any inherent understanding of what the hell dx really means, or why the chain rule applies. The only two math topics I didn't understand in high school were matricies and calculus, and this is, I believe, due to the inability of the teacher to explain what was fundamentally occurring. Sure, matrix multiplication follows a set of defined rules for element multiplcation and addition, but there was no explanation of why we do that, or what it's trying to accomplish. This is akin to my fifth-grade teachers that gave us homework after homework of multiplying 4 digit numbers by 4 digit numbers. Okay, after doing a few 2x2 numbers, or an occasional 4x4 you can learn the methods, but this was ridiculous. We weren't learning, we were being trained as monkeys to follow through a multiplication algorithm, without even understanding what multiplication implies, or why we were applying our cookbook methods. For instance, "why do we shift in an extra 0 at the units digit when we multiply by the 10's digit?". Did the teachers even understand this? This is why I strongly believe in word problems, which reveal why math operations are occuring, and how you'd use them. Physics is the word problems of calculus. When i went to college and majored in physics, that's when calculus finally made sense. "Oh, I see. We want to sum the work this particle does as it moves across this nonlinear force field, so I'll sum a set of infinitesmal forces, dF, at each infinitesmal point dx in space. Hey, when I write out the summation equation, that's an integral. Gee, now I understand what the hell I was doing in high school." I knew what the upper-case SIGMA meant in math, sum an integer set of discrete numbers. If only my teacher said an integral was exactly the same thing, but occuring through all points, not just discrete integers, it would have made sense. But I had to wait until college physics for that. There are many other calculus examples. For instance, one set of problems we did in high school was spin a curve about an axis, and determine the surface area of the resulting solid. we would just "plug and chug" the curve into the magic formula for surface area, and we get the answer. "Where does this formula come from? What does it mean?" If only my teacher said that what we're really doing is breaking the object into a set of small cylinders, and summing the surface area on each of these, I could have understood. Relevant examples also exist in more advanced topics. Vector calculus doesn't really mean much at all on it's own. What is a Gradient, Divergence ,or Curl really? Okay, I can figure out what the curl of a vector field is, but what is the significance? And what is the point of Stoke's and Green's theorems? Again, these made sense once I needed to apply these to physics, which provided the word-problem analogy to these concepts. The fundamentals of matrices made sense once I got to quantum mechanics, and now I can see how they apply to all sorts of algebraic systems. In an applied math class I took later, on the first day the prof related an algebraic system to solve to an electronic network. The implications of matrices suddenly made perfect sense, and the light bulb in my mind just suddenly switched on. I believe this wouldn't have happened if the theory was not applied to a real system for understanding. You write: integrating is something people just don't tend to do, on a day-to-day basis. Yes, but you don't need to do something every day in order to present a concrete example to make an idea easier to understand. Just my $0.02, though.
Perhaps UK school law mandates the purchase of an 'official' product?
Don't get me wrong, there definitely are really boring and unfunny Simpsons episodes, but throughout each season there are certain episodes and moments of pure hysteria.
On an unrelated note, has anyone seen 'The Critic'? Now that's a show that has been unjustly cancelled twice, but when it's on a roll, it's really on a roll! Cartoon Network has reruns of it sometimes, but there's only like 15 or so episodes. If given a longer chance, I think it could have become totally awesome. [Note, some episodes of it are painfully cheesy, but the parts that are funny are enough to give your diaphragm a year's worth of exercise). IMHO, of course.
How do the rest of you guys feel about the year numbering scheme. Minor versions could be like MyLinux 2000.0, and MyLinux 2000.1, or similar. Maybe even something akin to the WINE packages.
Are there other schemes that may be better than just Mandrake 7.x or Mandrake 2000?
I've used RedHat 5.2 and 6.0, and Mandrake 6.0 and 6.1. The way Mandrake was introduced to me, which seemed correct, was like RedHat, but with the bugs fixed and extra goodies included.
If you want support or help, try the mailing lists, they're really informative! One of their techies, Axalon Bloodstone, slaves away to answer multitudes of questions posed by newbies and experts alike. Find the link from their site
On a different note, I also prefer Mandrake, but what sometimes ticks me off is the Pentium compile optimizations, as I must hack things, or use a differnt distro, for 486 machines.
You're view of only 'the product' is far more sad, if you ask me.
Would you buy a pair of "better" sneakers if you knew that NIKE was using cheap child labor in a third-world country to build them?
Would you buy "better" lumber if you knew it was old-growth wood from the rain forest?
If you were alive 200 years ago, would you buy Plantation cotton from the American south, which was harvested by slaves, or maybe buy slightly less-quality cotton grown by free workers?
The political agenda behind the product often matters, as you can see. If we aren't willing to stand up for what we believe in, we may as well not be human. Try taking a stand for once, and follow what you believe in. You may feel pretty good about it.
"In a world without walls, who needs Windows" - Someone from LinuxToday
"In a world without walls, who needs Windows" - Someone from LinuxToday
So, he smoked them all, then called the insurance company and reported the loss of his cigars due to a series of small fires. They wouldn't pay up, so he took them to court. In court, he admitted smoking the cigars, and won because the court stated the contract was worded to protect the cigars against fire.
However, the scales of justice wouldn't remain tipped. The insurance company then filed charges against him on 24 accounts of arson. He was found guilty, using his evidence related in the previous case where he collected the insurance money. Ultimately I think he was thrown in jail.
That's a good example of the system working to punish those that would otherwise take advantage of it.
"In a world without walls, who needs Windows" - Someone from LinuxToday
"In a world without walls, who needs Windows" - Someone from LinuxToday
I just want to chime in here. It isn't just the fact that we're aiming for 24 bits (ie, 144 dB) SNR here, but it's also the sampling rate that matters with respect to difficulty. It's a general trade off with analog-digital converters (as well as most circuit systems in general) between accuracy and speed. There are a number of 24-bit ADC's that work quite well, I believe. They use dual-slope current ramping (amongst other methods) to really get an accurate level of the voltage to be sampled. HOWEVER, and it's a big however, these things are slower than molasses.
A quick stroll by the Analog Devices website shows a bunch of 24-bit AD converters which I'm sure are up to specification. However, none samples higher than about 1 kHz. Maybe somewhere else in their page are other converters, but this is a rough indication of what's available today. The faster you go, the more you sacrifice SNR. So, to be repetitive just one more time, it's not the 24 bits that hurts you, but the combination of 24 bits at 96 kHz which makes it hard.
"In a world without walls, who needs Windows" - Someone from LinuxToday
So, then, acoustics would mean nothing to you. Why bother with the expense of a stradivarious as opposed to a cheesy keyboard emulating a violin. It's all just the same notes anyway. :-)
I'll really be in awe when you just look at a CD, and can appreciate the tunes on it. Or even a record, for that matter. :-)
"In a world without walls, who needs Windows" - Someone from LinuxToday
As to the above post referring to frequencies above the range of hearing that refer to location, these can occur way into the MHz! I've been told (not personally witnessed, though), that if you take a channel of audio sound and play it into the right ear, and play an identical audio channel, only delayed 1 us, into the left ear, you can notice a very certain direction to the music. Change the delay, and you've changed the direction al response of the sound.
This is why very good audio amplifiers should have bandwidths up into the MHz, and not just rolled off at 20 kHz or so. CD-quality sound is pretty good, and can still produce these MHz-type effects, though it's been sampled at 44 kHz. How, you wonder? Well, it has to do with the 96 dB (16 bit) SNR. Phasing of a sine-wave can be determined rather precisely with the 96 dB of range, due to the 65536 distinct levels each voltage point can be. There's enough vertical resolution (amplitude) that horizontal spacing (phase) can be determined rather precisely.
Of course, moving beyond the 16-bit level of SNR is pointless, unless you've got the equipment to handle it. Ie, inherent non-linearities of the decoupling caps between amplifier stages is a killer. If your system is using a cheesy electrolytic here (the horrors), rip that puppy out and use a polystyrene cap. Eventually you may want to bypass this and DC couple all the stages. Also, use monster-cable to the speakers, even any small resistance from amp output to speakers will form a divider with the speaker cone, and introduce isolation from the output driver, which will distort your frequency response. Also never use a passive crossover, use an active one before your final amplifier. This doubles the needs of amplification, but hey, you're an audiophile, right? You'd be surprised by the supposed high-quality audio systems that still throw in a cheapo 50-cent cap just to save a few bucks. Ack!
"In a world without walls, who needs Windows" - Someone from LinuxToday
Upwards on this thread it stated that one could make changes under the BSD license and release an executable without releasing the source code. Doesn't this imply that they can thus also produce MyVeryOwnBSD, placing themselves in the MyVeryOwnBSD governing elite in the process? (of course they had better be a damn good coder to justify it).
"In a world without walls, who needs Windows" - Someone from LinuxToday
Maybe NT is for True Neutral, only with the letters reversed because they messed up the big-endian with small endian, or similar.
"In a world without walls, who needs Windows" - Someone from LinuxToday
Lots of interesting problems and propositions appeared. For example, getting through the ice. Do you drill, or use an RTG. RTG seems like the best way to go, but you cannot just 'turn' the RTG 'off' once you're through the ice. Hope it doesn't mess up any discoveries that may await. If you 'drop' the RTG spike, as the poster suggested above, then you had better either have some other sort of power source on the hydrobot, or have your several km of tether to the surface craft (see below).
Another problem is power, but if you've got that RTG onboard, you may be cured of this. If not, then you must run a tether to some sort of power source (solar panels or similar) down a several km-long tether to power the hydrobot.
Also interesting is comm. If you run a tether, which is a royal pain in it's own way, you've got many channels of fiber to talk through. Otherwise, RF transmission through many km of ice and water is too difficult. Another possibility is using a sonar-based modem, but can this transmit from water through several km of ice, or does it reflect off the ice?
These just off the top of my head. Very tough problem, considering the huge initial expense (in terms of mass, power, and even money) to get to the reaches of Europa. Better have lots of reduncancy and other plans in case things don't work right (which of course, they won't).
"In a world without walls, who needs Windows" - Someone from LinuxToday
Note - I don't work for these mags, nor am I being paid by them, etc. I am promoting them merely because I think they're awesome.
Circuit Cellar Ink is an excellent magazine focusing on hardware and software interaction. Articles on embedded computers and software/firmware implementation, with real life examples of what techs in the business are doing. Current issue deals with making a MIDI sustain pedal, details of dual-slope analog-digital converters, Infrared Device technology and how to use it in your own projects, and other informational articles such as description of the current status of HDTV. One really awesome article that ran 1 or 2 months ago dealt with an engineer homebrewing his own microprocessor based on the Z-80 instruction set, but with little goodies thrown in. Way cool. Someone in an above thread mentioned they liked the ads in some good computer magazines. Same with this magazine, all sorts of embedded-related ads. Oh yeah, this mag is big on the PIC and Basic Stamp. If you don't know what these are, take a look!
Another good one is embedded systems programming . I haven't had the time to read the current issues in-depth, but I keep meaning to do so. Going through my father's collection back a few years, there are some majorly good articles here. This mag devotes itself, obviously, to embedded systems programming. Current issue deals with communication issues, real-time stuff, embedded web servers, etc. Another good thing is their tech columns, which deal with real-life examples of coding. They've had a series aimed at moving C coders (like me) to C++ through specific examples. Also mathematical applications, such as a multi-part indepth review of Z-transforms and Fourier Transforms, and DSP programming, and how to implement these in your systems. Way cool stuff, too, IMHO.
Just for browsing the net, an amazing source of info is from Don Lancaster's Lair . Rightly named the guru, this guy is a tech genuius (sp), and does all sorts of great stuff like working with PIC's inside and out, programming in raw Postscript to make his printer act as a peripheral computer, and other stuff. Go check out his page. Now! Engage.
"In a world without walls, who needs Windows" - Someone from LinuxToday
"In a world without walls, who needs Windows" - Someone from LinuxToday
"In a world without walls, who needs Windows" - Someone from LinuxToday
For example, do people in the auto business patent the idea of a plate on the floorboard, that when depressed, through a clever system of force transfer, opens and closes the throttle valve? Or the use of hollowed-out rubber torii (toruses?) which will not only support an automobile, but when rotated, propel it forward.
I know about the strange genetic patents, but are computers and the human genome the only areas that seem to be exploited by these ridiculous patents?
Ummm, well how about the Voyager spacecraft travelling through space? They have mass, E=mc^2, so they thus have energy, and they surely appear to be 'carried' through this vacuum medium. Of course, one can claim that space isn't a pure vacuum but has a few hydrogen particles per cubic meter, but then again that is what light (and gravity) is travelling through from the sun anyway.
I think you may have meant to accord with the notion that space (vacuum) has no ether, thus the logical way of explaining energy being transferred through it is as a particle, because what can the E&M or gravity waves oscillate to carry them forward?
Sorry if I'm misinterpreting your point. It just strikes me as a not-well-understood notion (from my point of view, that is). I cannot wait to get to grad school and do E&M again (as well as GR and QM)...
Haha, i shouldn't be so hasty to submit my words. Of course, I meant to say, "We'd be all up a certain river without a paddle"
If he's so worried about us pesky humans playing God, why is he publishing on an online medium? I mean, weren't we playing god 100 years ago when Faraday and Maxwell were working out the basics of E&M, and Shockley/Bardeen/others again with solid state research to bring us the transistor, which directly leads to the computer on his desk.
In fact, metallargusts of antiquity were playing God as well, so we shouldn't use metals, lest we upset the delicate balance of the universe. Wait, he does denounce the combustion engine. I guess this implies he walks/bikes/etc wherever he goes, so as not to upset the ecosystem.
He seems to be the only clear-thinker among us, if it weren't for him I'm sure we'd all be up a paddle.
Everybody keeps mentioning the fact that a Tempest can scan the RF noise for 1000 yards to capture video signals. How does it distinguish between multiple monitors within this range? Ie, can it pick only one of many sync rates? or does some funky DSP filter out the other monitors? Or do other monitors distort the signal enough that it can act like a jammer?