Re:we all know what a disaster Freon was... try ag
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Microsoft Freon
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· Score: 1
Note: Fscking Slashdot doesn't support <pre>, <sub>, or <sup> anymore, so the following may get ugly. Disclaimer: My family business is in the HVAC industry, albeit not at the design and manufacture end of things.
I'm still trying to figure out why this is so widely accepted. If anyone has a good answer, I'd be interested (seriously). How does a gas as heavy as chlorine rise above lighter gasses to the ozone layer? Chlorine is, after all, the catalyst in R-12 which is supposedly destroying the ozone layer, while at the same time we're complaining of high ozone content in the lower atmosphere due to vehicle emissions. Is the heavy gas Chlorine gas really making a miraculous trip into the upper atmosphere to destroy O3 while leaving the Ozone down here intact for us to breath? Or did DuPont buy another government backed scare to make more dough?
My understanding is that O3 has a half-life of something on the order of 15 minutes under normal tropospheric conditions, and is unstable enough even in the stratosphere that the ozone layer wouldn't exist if the Sun's UV light weren't constantly breaking it down and reforming it. That means that it's not very surprising that it doesn't migrate very far from where it forms. However, the atmosphere is highly turbulent, so the mere fact that a gas is heavy doesn't mean it won't find its way to the stratosphere (given enough time).
What makes commercial CFCs different from volcanic emissions is that CFCs are extremely stable -- just about the only things that break them down are fire and hard UV -- whereas most natural chlorine-containing gases are highly reactive. That reactivity serves to bind the chlorine from staying suspended in the atmosphere for long periods of time before being bound in less-reactive solid or liquid compounds that can no longer circulate. Those same properties that make Freon so attractive as a refrigerant compared to other hydrocarbons also make it a royal b*tch on the environment, because it bypasses that binding process.
Here's the (proposed) chemistry behind it, if you're interested. The reason chlorine is such a bitch is that chlorine readily forms the following progression of molecules, all of them radicals that are one valence electron short of a happy meal (so to speak):
This means that, once the chlorine is released from the CFC molecule, it can react with ozone at a faster rate than the amount of ozone produced by UV bombardment. Discarding output energy that would be re-radiated as lower wavelength EM, here is a list of some of the partial reactions of the process, at least so far as I understand it (IANAC, but I'd love for one to step forward and correct me if I'm wrong):
Note that, in the natural cycle, 4 O3 molecules will absorb up to 4 UV photons per iteration (slightly less in practice due to ozone's natural tendency to break down without help), whereas the chlorine radicals complete an entire iteration using only 1 UV photon. Even given that an O2 molecule can form two O3 molecules using the energy of a single UV photon, the chlorine still makes the O3 breakdown process ruthlessly more efficient.
I used to be skeptical of the CFCs => ozone depletion arguments, but over the last decade I have to say that the evidence is mounting in favor of the theory. Unless someone else can come up with an alternate mechanism, one as supported by the evidence as the CFC theory, I for one will presume that the CFC theory is, if not perfectly correct, then the best fit for the evidence that we have.
I may stick with gcc-2.95.x until the kernel is officially gcc-3 ready.
My kernel (stock 2.4.18) was compiled without a hiccup using GCC 3.1, and it's been running just fine for 3 weeks now. GCC 3.1 is a dream for everything except (a) C++ apps dependent on C++ libraries (a true bitch sometimes), and (b) software that depends too much on GCC 2.9x bugs (thankfully, such software is very rare).
As for the Alpha, I tried to port my application to Alpha when it first came out, and there was a problem. It seems the Alpha processor could not access memory at the byte level. All byte writes had to merge the byte in question into a 64-bit word to write back into memory. PowerPC has no such problem.
My understanding of it is that the hackery required to access non-aligned data requires a substantial cost in terms of either silicon or performance, on any processor (including x86). The Alpha designers (and most RISC designers, for that matter) chose to leave it unimplemented in the hardware, leaving it to the compilers to align everything to the native word size like they should be doing anyway.
The "correct" response to that situation would be to store each byte in its own machine word. Yeah, that wastes a lot of memory, especially if you have a lot of boolean flags, but -- more often than not -- it's not nearly as expensive as the performance tradeoff, even if the memory is owned by a single thread. A lot of the comp.lang.c newbies (and a fair number of non-newbies) who first see automated alignment get confused and want to know how to pack their structs, not realizing that it will probably make their program run slower unless they are doing some very specific things (e.g. their code's performance is dominated by calls to memcpy(3)).
Re:Are script kiddies smart, dumb, or just lazy?
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Tracking Mafiaboy
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· Score: 2, Interesting
Sounds like inattentive ADD. [...]
<anecdote>
I was diagnosed by a psychiatrist, a little over a year ago, with the non-hyperactive variant of ADD. In the last year, I've been a more productive programmer than ever before, and I'm actually on my way toward getting a real job based on my Linux networking knowledge.
The downside? I'll probably be stuck taking Adderall (dextroamphetamine, basically legal speed) for life if I want to keep my focus. For the last week, I've been going without in an attempt to wipe out my tolerance (FYI, take my advice and don't deviate at all from what the prescription says without first running it past your doctor, no matter how innocuous the change seems) and I've seen myself revert completely. It's been a very stark contrast between what I've considered "normal" for the last year versus what I'd considered "normal" before, and it makes me appreciate the reality of ADD that much more.
...until the DVD CCA realizes that they will piss off the software industry, severely, if they succeed in their current line of litigation. If code is speech, then it can be copyrighted but the 1st Amendment applies; if code isn't speech, then the 1st Amendment doesn't apply but it can't be copyrighted. Ergo, if the DVD CCA wins, the U.S. government will have to stop prosecuting for those who infringe the "copyright" of software. You think Microsoft is pissed at Linux? Wait until Disney tries to hack their balls off!:-P
Actually, the mathematics behind this movies is a crap (and a big one). But I still like this movie, the soundtrack is really cool.
I, for one, agree on both points. While the movie was entertaining, the math was ridiculous. The "magic number" was arrived at by nothing more than wishful thinking that devolved into numerology. Worse, the actual number pi has very little to do with spirals, and certainly no more to do with spirals than e and i do, so the entire name of the movie is bogus. Pointing out the prevalence in nature of fractals, the Fibonacci sequence, or the Golden Ratio would have made the movie more plausible from a mathematical standpoint.
But, again, the movie was quite good, and the soundtrack was intriguing enough that I bought it almost right away, and I probably would have even if it hadn't included a track from my favorite group, Orbital. Too bad they didn't pick a different Orbital song; P.E.T.R.O.L. is OK but not really representative of their work.
Re:Society Only Appreciates Scientists In Movies
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Enigma
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· Score: 1
Given that the government basically gave Turing three options:
Go to jail for life
Take breast-growing and male-libido-impairing injections of estrogen for life
Commit suicide (the implicit out)
... I can't say I wouldn't have done the same in his place, although I probably would have tried to immigrate to a more gay-friendly country first. It's really a shame, too, as some of his most brilliant work was in the latter part of his life.
The LONGER the material is radioactive the LESS harmfull the radiation from the material is.
Yup. For instance, Uranium 238 has a half-life of about 4 billion years, which means that a given quantity of U-238 is safer than the same quantity of just about any other radioactive isotope.
The problem with PU isn't the radioactivity it has, it is the fact that it is a heavy metal which is very toxic much like lead. With soemthing that stays "hot" for a 100,000 years the toxicity of the material is what your concerned about not the radiation.
This part is incorrect. Pu is indeed a heavy metal, but it is almost completely insoluble in water (with a concentration expressed in parts per million). Another heavy metal is Bi (bismuth), the active ingredient in Pepto-Bismol. If Bi were water-soluble, Pepto-Bismol would be a deadly poison, as it is immediately right of Pb (lead) and two rows down from As (arsenic). (Bi also has the interesting distinction of being the heaviest element with at least one stable isotope.) In addition, Pu-239 (both the most common and the most stable Pu isotope) has a half-life on the order of 20,000 years, making it a rather "warm" isotope. To get a medically significant amount of Pu into your bloodstream by ingestion in a single incident, you would need to swallow a significant fraction of a kilogram of the metal, which would be more than enough to blast your intestinal epithelial cells with a strong alpha burst. The 100,000 year figure in the article takes into account (a) secondary radioactivity induced by the waste in the surrounding materials, and (b) the composition of the waste. Fission waste is a blend of many radioactive isotopes of widely varying half-lives: some "hot", some "warm", and some "cool".
If the U.S. bureaucracy would stop sheep-bleating and pull its collective head out of its ass and pay attention to ongoing fission research, they would find out that the Yucca Mountain project is totally unnecessary because the time it takes for fission waste to cool could be dramatically cut by re-"burning" the waste mixed in with fresh fuel, allowing the "warm" waste to become "hot", thus reducing the danger to a span of a mere century or two at most. They would also start the gears turning on building plants based on the fuel-pellet design operating in Europe, where an overheat of the (liquid metal) coolant causes the fission reaction to spontaneously stop without human intervention and without risk of hydrogen explosions, eliminating the most prominent dangers of traditional fission reactors.
Unfortunately, they're opposed to the former because it's the same process used to turn U-238 into Pu-239 in the first place, making it a "security risk" (Waste recycling is a security risk, but multiple tons of highly radioactive waste stored at a well-known location for 100,000 years isn't?), and they're opposed to the latter because the voting public is anti-nuclear-anything. (Better ban smoke detectors next, they use Americium created in fission reactors!)
Just out of curiosity, have you ever taken a class on nuclear energy? The "fact" that a tablespoon full of plutonium could kill every human on earth is the most blown out of proportion ridiculous fact ever. Consider this, uranium is a natural element. It exists everywhere, everywhere!...
Actually, it's not the radioactivity of plutonium alone that makes it so lethal. It is a very powerful carcinogen because the body accumulates what it absorbs over long periods of time, although its near-insolubility in water reduces its effective toxicity to far below what many people believe. However, if it reaches the bloodstream, it accumulates in the bone marrow and in the liver, where it has a half-life of elimination of 70 and 35 years, respectively, and inhalation of fine Pu dust can cause significant alpha exposure in the ~500 days that it takes the lungs to eliminate it.
To put it simply, it's neither a massive threat nor a relatively benign substance, and it gets a lot more bad PR in the press than other, much more worthy, scapegoats.
A friend of mine came across a site describing how to uncap SURFboard modems. Being the inquisitive hacker-in-training that I am, I read through their instructions, theorized what was ACTUALLY happening (as opposed to what they SAID was happening), then launched Ethereal and confirmed it. I've made some further discoveries since, but I've since rebooted my modem (which wipes the uncap) because I have an ISP that gives very fair caps (we have a business connection, ~$80/mon, roughly 8Mbit down and 570Kbit up). Here are my discoveries:
The SURFboard cable modem series downloads its parameters from the ISP via TFTP during the boot sequence, grabbing a fresh copy each time it reboots, and rebooting each time it loses sync beyond hope of recovery.
The configuration file is stored in ASN.1 BER format, which is very nasty so I won't discuss it further.
The modem publishes lots of critical information via the SNMP "public" community string, including the TFTP server address.
The flaw is that, during the modem boot, the modem downloads a TFTP config file from the IP address named in *its* DHCP ACK packet (the DHCP transaction that gives the modem an IP on the ISP's private network, which users should ideally never see). When it sends the TFTP request, it sends it to both sides (ISP and client), and accepts the first response that it gets.
Later revisions have a slight fix; however, the Ethernet interface is still up and running in promiscuous mode, so rapidly pinging the modem as it boots will lodge your MAC address in the modem's ARP cache, making your computer receive the TFTP request as before.
With proper filters in place in the ISP network, clients would never be permitted to access internal ISP resources like the TFTP server. With no known-good bootfile for your ISP, uncapping is much trickier.
The same SNMP interface also publishes the upstream and downstream caps, allowing the ISP to trivially scan for modems with settings that don't match the ISP's own bootfiles.
Cats don't have such great vision, really. In general, they have trouble focusing on something unless it's moving. Stationary frogs would present something of a problem, though certainly not a showstopper. My girlfriend's cats will go to any length in order to get some Pounce.
True, cat vision isn't as spiffy as most people believe -- it's a simple tradeoff between rods (night vision) and cones (vivid color and sharp definition) -- but I believe that cat hearing would more than make up for it in the case of these frogs.
I'm not sure what theories they were, but my physics professors have told me that Einstein has been proven wrong before.
Interesting links, although I won't be holding my breath while the results are checked. As one physicist is quoted in the NYTimes article as saying, "You have to get down on all fours and claw through the details to see such a small effect." However, even if the results are accurate, it won't mean that Einstein's General Theory of Relativity will be tossed out the window like a used tissue.
Just as Newton's physics are mostly right, when restricted to the realms where they are applicable, Einstein's physics are accurate to such a degree that any new physics will only need to be dragged out for the realms where Einstein's physics are found to be inapplicable. The Standard Model of Physics can be summed up as "use Quantum Chromo Dynamics for the EM, weak, and strong forces; use General Relativity for the gravitational force". The incompatibility between GR and QCD is quite striking, but the candidates to replace the Standard Model seem well on their way to making GR's tensor calculus look like simple algebra, making it likely that GR will still be the theory of choice for situations where it is mostly right.
Re:Infinity is a very difficult concept to even..
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Big Bang or Cosmic Crunch?
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· Score: 2, Informative
no matter where you are in the universe, the laws of physics are the same for all inertial (constant velocity) frames
Are you saying that light will always be moving at c ?? Just because light enteres a medium, doesn't mean that time slows down because light is slowing down. The reason light slows down is because it has to exite every atom that it encounteres, then be thrown out again.
That's why I mentioned that c is the speed of light in a vacuum. The speed of light in a non-vacuum medium is slowed down, to c divided by the refractive index of the medium (1.33 for water, for instance). Basic optics, known well before Einstein's time.
They've even collected good evidence that the speed of light has changed over time... I'm really starting to doubt einstein.
Citations, please?
Suppose you're on a hypothetical train traveling at a constant velocity of 0.5c towards a friend, and you point a flashlight straight forward and turn it on. You perceive the beam of light as traveling toward your friend at speed c; however, your friend sees the beam of light as traveling toward him at speed c, and not speed 1.5c. How can this be?
Take a jet for example. Say it it traveling at mach 2, and it fires a missle in which the missile maximum speed is mach 5. Now there is a stationary SAM site on the ground that will be blown up in a little bit... but the SAM site sees the missle coming at him at mach 5, and not mach 7. How can this be? Because you're missing the obvious....
I'm not the one missing the obvious. Unfortunately, Slashdot won't let me draw some ASCII art to explain, but I'll try and describe it in terms that you'll understand... remember that airspeed is speed relative to the air, and that air is essentially stationary compared to the ground when you're talking about Mach speeds.
From the perspective of the SAM site, the plane is moving at speed Mach 2 angle 0 with respect to the ground, then launches a missle that quickly assumes a path in which it is traveling at speed Mach 5 angle 315, which happens to be perfectly aimed such that it will impact the SAM site.
From the perspective of the plane, the SAM site is zooming underneath at speed Mach 2 angle 180. It launches the missle (let's presume it's guided), then observes as the missle fires up and assumes a path of travel with speed Mach 3.57 angle 293.5. The missle looks like it will fall short, except that the SAM site rushes underneath the missle just in time to be hit. Stupid SAM site!
In the train example, we have a train traveling at speed 0.5c angle 0. You are standing on the train, and your friend is directly in front of the train by a safe enough distance that he'll be able to sidestep the train when it gets close. So, from your perspective, your friend is rushing toward you at speed 0.5c angle 180, and the beam of light is rushing away from you at speed c angle 0. What does your friend see? According to Newton's mechanics, he should see you rushing toward him at speed 0.5c angle 0, and the beam of light should be traveling at speed 1.5c angle 0 (simple trigonometry -- you add two vectors with the same angle by adding their magnitudes). In reality, as confirmed by countless experiments, the most famous of which are known as as the Michelson-Morley experiments, your friend perceives the beam of light as traveling at precisely c. If you fire a railgun from the train with a slug that travels at speed 0.5c angle 0 relative to you, then your friend will see the slug traveling toward him at speed 0.8c angle 0. These results have been confirmed by many, many experiments, so the burden of proof is on Einstein's doubters to show -- using repeatable and accurate experimental methods -- that an alternative explanation can exist. The physics department at the University of California at Riverside has an excellent site introducing physics, including thesetwo pages that explain why the ether theory from the late 19th and early 20th centuries is thoroughly debunked and cannot be modified to fit the facts without becoming an unfalsifiable hypothesis (i.e. a matter of faith).
Light does have it's speed limit. The easiest explanation for that would be a drag in the ether that keeps it from exceeding that speed.
Again, see the above links for an explanation of why ether theory cannot be falsified if it is modified to be consistent with our existing knowledge.
You perceive the beam of light as traveling toward your friend at speed c
That is the mistake in the example... It is trying to prove relativity, but without relativity, that sentence would be false... You can't prove something by initially assuming that it is true; using the theory within the explanation for the theory.
The statement assumes that relativity is true, but it's a testable and falsifiable statement that, if it were false, should be trivial to debunk. Despite multitudes of measurements and experiments, especially by the people who passionately desired to show it to be false, that very statement has not been found untrue even once.
Didn't Einstein fail math?
Yes and no. He understood math quite well, but due to dyslexia he couldn't deal very well with the rote memorization and mechanized learning required of him by the school system. He eventually learned to deal with it well enough to get excellent grades.
Re:Infinity is a very difficult concept to even..
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Big Bang or Cosmic Crunch?
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· Score: 5, Informative
(Disclaimer: IANAP, although I'm enamoured with the topic.)
Humans are starting to think of the universe in wrong ways. My main beef is with time. People think of time as a physical dimension that is effected by matter.... this, is only partially true.
They have sent up jets with atomic clocks to test einsteins theory of gravitation effecting time, and they think of it to be correct. The more gravity, the slower time moves. But is it really making a change to some 4th dimension, or just the speed at which the subatomic particles within matter move?....the latter is certianly acceptable. Since matter slows down, then "time" relative to that slowed matter would infact slow....
It's not just subatomic particles that slow down, which is Einstein's true stroke of brilliance. Einstein began down the road of Special Relativity by postulating that Newton's Principle of Relativity -- no matter where you are in the universe, the laws of physics are the same for all inertial (constant velocity) frames -- is correct. One of the laws of physics, courtesy of Maxwell's Equations, requires that the speed of light in a vacuum, c, is a constant. So, if both of these postulates are correct, then everyone will agree on the value of c in all inertial frames.
This deserves some illustration. Suppose you're on a hypothetical train traveling at a constant velocity of 0.5c towards a friend, and you point a flashlight straight forward and turn it on. You perceive the beam of light as traveling toward your friend at speed c; however, your friend sees the beam of light as traveling toward him at speed c, and not speed 1.5c. How can this be?
The answer that Einstein came up with, and the only known set of physical laws of motion that is consistent with both Maxwell's Equations and the Principle of Relativity, requires that your friend sees you as flowing through time at a slowed rate, whereas you see him as the one who is slowed down. With some extra geometry not far beyond a high school math student, it's not hard to prove that the length of (you|your friend) must contract; also, some modifications to Newton's Laws are required in order to make the laws of inertia and momentum self-consistent, making (you|your friend) appear to have more mass.
It is an inescapable conclusion of Special Relativity that the actual flow of time slows down -- General Relativity, the theory which tied SR and gravity together while introducing time as a 4th dimension, is not even required to prove this result. The very CRT that you're using to view this article right now could not possibly exist if Maxwell's Equations were grossly wrong, meaning the only way to prove SR grossly wrong about the flow of time would be to disprove the Principle of Relativity -- by demonstrating that the laws of physics vary depending on where you are in the Universe!
(A day late, a dollar short... I doubt anyone will read this. Oh well.)
I agree with Schneier that software liability is the only thing that can fix the sorry state of today's commercial software. I also agree with the Slashdotters who say that making authors of free (either meaning) liable would kill off the practice. When I first pondered this dilemma before, I came up with an idea so fiendishly perfect that I'm sure tons of people have thought of it before: make the degree of liability proportional to the cost of the software!
The Microsofts and Oracles of the world who make expensive, broken software will have to change one or the other or be sucked dry by damages awarded in liability lawsuits. On the flip side of the coin, the freeware and Open Source/Free Software communities won't have to change anything, and the shareware folks would be protected by the fact that most people who use their stuff never pay for it, perhaps even encouraging more people to buy shareware so that they might have legal recourse if it ever fails in the future.
Our problem was with storage of the game so that it could be accessed by the computers in the lab. I was making a hobby out of finding places on the network to hide the game where we actually had write privileges. We had a big Novell network running all the systems, and it was amazing how many places we had write privileges.
Ah, Novell. Back in high school, all the PCs at our brand new "state of the art" school (the building was finished in 1994, and the PCs were 386DX/25's with 4MB RAM, IIRC, running MS-DOS, and were never upgraded once in 5 years -- don't let me get started on THAT rant) were sitting on a Novell network. Most of the network shares were read-only, but it seems that whenever the admin had trouble getting a new program running from the network, she would make its directory read-write.
The Pascal and AP Comp Sci classes had TONS of fun with a globally writable TURBOPAS directory; it started with everyone running the sample Breakout game, continued with some hacked-up source code mods, and eventually led to a ton of Pascal-written games and toys, including my own chat client. At the time I didn't know that Ralf Brown's Interrupt List existed, and only knew the barest of INT $10 and INT $21 calls, so I wrote it using a shared file to represent each "room" which each client would attempt to open and exclusively lock once per second, display any changes, and close. Scaled like shit, I imagine, but it was great fun once about 10-20 people had discovered it and were online at a time. (My/WHO command that turned student ID's into names was quite a shock to some of its abusers.:-P)
Nah - I don't buy this - if "small errors" crept into data burnt onto CDs on a regular basis, half the software I downloaded and burnt would be corrupt. It never is. My burner is ancient. Therefore I don't think it likely that anyone else's writes with a detectable error rate. I take your point - that errors could creep in if a burner didn't form the marks well enough, and the more you copy a thing, the more chance of this happening - but I have yet to see it, and I burn quite a lot of stuff (all those Q3 mods n maps are quicker to download at work, and transport on CD:)
As others have pointed out, there is a difference between audio and data CDs. A Red Book CD-DA disc has sectors of 2352 bytes (1/75th of a second of audio), after the basic ECC is processed. A Yellow Book CD-ROM uses a second layer of ECC that turns those 2352-byte sectors into 2048-byte sectors, adding enough redundancy to deal with the fact that arbitrary data can't just be interpolated like audio can.
Ok, initial comment on this story has been very negative, but... The original Pons et. al. findings also claimed neutron production.
The Pons and Fleischmann experiment, if it had actually worked as well as they said it did, would have killed them from the neutron radiation. They didn't bother to do even the most basic accounting of what was going where and when, and they never compared what they measured to what they would have expected to see had they actually produced fusion. Worse, they hid details from their experiment for a considerable period of time, before saying "Wait, you weren't doing it right!" and giving the details of their palladium electrodes when the evidence was mounting against them.
The current experiment, even if it is wrong, at least was performed by experimenters who appear to understand the importance of collecting as much information as possible before hypothesizing models that explain it. The trouble with reproducibility might indicate a problem with their instrument calibration, plus the measured neutron flux and the detected tritium are in disagreement on how much fusion is taking place. However, at least the experimenters acknowledge this, and give a detailed enough description of their setup that others can try to reproduce it. It probably won't pan out, but I won't hold it against them.
Re: It's my trumpet and I'll blow it if I want to
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Apple Licenses CUPS
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· Score: 1
Or just use lpd. I've been using lpd/lpr, samba, and netatalk for at least 5 years to print to various printers, including HP and Epson inkjets from Linux, BSD, Irix, Solaris, Windows (98,NT,2K), and the occasional rare MacOS.
If you like lpr/lpd, odds are that you'll adore LPRng. Throw together a handful of options in a pair of well-commented text config files, and you can set up ACLs, Kerberize everything, and not have a single program running as root or installed set[ug]id.
The only system known that MAY get around this is watermarking, in which it shouldn't matter WHERE you capture it in the chain, you can't make it input to any other DRM device because it will recognise the watermark and prevent you from using the content.
It's easy to deduce why DRM hardware that uses "positive" watermarking cannot possibly work in general. If the watermark is inaudible, then any decent lossy compression algorithm will remove it or scramble it beyond recognition. If the watermark is audible, people won't buy the music.
However, I can envision the nasty scenario where the DRM hardware refuses to play audio UNLESS it detects a valid watermark. Such "negative" watermarking has the actual potential to work, particularly if the watermark is used to encode a cryptographic signature of some digest that (A) can be generated algorithmically from the music and (B) is invariant to "reasonably" lossy compression. (Ssh! Don't tell the RIAA!)
Thanks. BTW, is there any background story to explain why they would put someone with INT=10 in command of a team with such an important mission?
My assumption has always been that they had enough very intelligent people (Carter, Daniel) in the team that the most important criteria for choosing a team leader was (a) someone who could think tactically on his/her feet, (b) able to command the people under him/her effectively, and (c) willing (even eager) to listen to the opinions of his teammates. That, combined with the fact that Jack and Daniel had worked together before and had a quirky understanding (in the Stargate movie) pretty much solidifed his place in the team.
It's not just women who find him attractive.:-) He puts off a very nice "I'm a geek, but I'll cuddle with you all night long" vibe (which I'm sure most of Slashdot doesn't need to know:-P). I'm mortified to hear that he's left the show (no Showtime, so I haven't been keeping up on SG-1), because he was my second favorite actor (after Amanda Tapping) and only by a slim margin.
I agree with his reason for leaving, tho -- weekly far-flung government conspiracies do NOT have a place in a show that's fundamentally about the joys (and terrors) of discovering the unknown.
The
biggest problem with the series from my POV is Richard Dean Anderson, who is either a really bad actor or else is doing a really good job on a really bad part. (I suspect the former.)
I think it's the latter. The problem, IMHO, is that he's a pretty decent actor but is mediocre in at least some of the creative, behind-the-scenes stuff that he insists on doing. Because of his level of creative control on the show, he's one of few people who gets to write his own character. I think he's shooting for a realistic (in D&D terms) 10 INT 17 WIS character in his scriptwriting, but is too close to the character to spot the flaws in what he does.
Is Linux 2.4 unstable? It depends on your perspective and luck. I'm running 2.4.8 and 2.2.19 (Debian potato) on my systems successfully; 2.8.9 thru.12 have been glitchy for me, especially when it comes to running big jobs that stress the VM. Haven't tried anything above.12 yet; I'm waiting for.18. My old cluster runs 2.2 simply because I have no reason to change.
Your mileage, of course, may vary.
I've been running the 2.4.13 Linus kernel on this system, and I have to say that it's the most stable 2.4.x kernel that I've tried. My uptime is currently 81 days and I have yet to tickle a bug. On my test box, I plan to try Marcelo's latest 2.4.x kernel out, but I had some bad experiences with.14 (the newest that I've tested).
A full T1 is (1.544 Mbps) usually comes in somewhere at about $1500/month. My cable modem from @Home (2.2 Mbps downstream / 128k upstream) costs $40/month. Is this starting to make sense to you?
Unless you want to pay $500/month for your cable modem, quit bitching that AT&T doesn't want you to saturate it with traffic 24 hours a day.
According to those numbers, a $1500 T1 connection costs $1 per 1029.3333 bits/second of bandwidth, which equates to full utilization of 128kbit/s upstream costing $124.35. These numbers are horribly skewed, however, because (a) bandwidth is cheaper to your provider when they buy it in bulk (OC-3 lines and such); and (b) the costs of a T1 are wildly inflated already (See: regional monopoly).
Slashdot Mirror
Note: Fscking Slashdot doesn't support <pre>, <sub>, or <sup> anymore, so the following may get ugly. Disclaimer: My family business is in the HVAC industry, albeit not at the design and manufacture end of things.
My understanding is that O3 has a half-life of something on the order of 15 minutes under normal tropospheric conditions, and is unstable enough even in the stratosphere that the ozone layer wouldn't exist if the Sun's UV light weren't constantly breaking it down and reforming it. That means that it's not very surprising that it doesn't migrate very far from where it forms. However, the atmosphere is highly turbulent, so the mere fact that a gas is heavy doesn't mean it won't find its way to the stratosphere (given enough time).
What makes commercial CFCs different from volcanic emissions is that CFCs are extremely stable -- just about the only things that break them down are fire and hard UV -- whereas most natural chlorine-containing gases are highly reactive. That reactivity serves to bind the chlorine from staying suspended in the atmosphere for long periods of time before being bound in less-reactive solid or liquid compounds that can no longer circulate. Those same properties that make Freon so attractive as a refrigerant compared to other hydrocarbons also make it a royal b*tch on the environment, because it bypasses that binding process.
Here's the (proposed) chemistry behind it, if you're interested. The reason chlorine is such a bitch is that chlorine readily forms the following progression of molecules, all of them radicals that are one valence electron short of a happy meal (so to speak):
Cl (would-be chloride)
ClO (would-be hypochlorite)
ClO2 (would-be chlorite)
ClO3 (would-be chlorate)
ClO4 (would-be perchlorate)
This means that, once the chlorine is released from the CFC molecule, it can react with ozone at a faster rate than the amount of ozone produced by UV bombardment. Discarding output energy that would be re-radiated as lower wavelength EM, here is a list of some of the partial reactions of the process, at least so far as I understand it (IANAC, but I'd love for one to step forward and correct me if I'm wrong):
(Normal O3 cycle:)
O2 + UV
2*O (cycle entry)
O2 + O
O3
O3 + UV
O2 + O
2*O
O2 (cycle exit)
(R-12 "eating" ozone:)
CCl2F2 + 2*UV
CClF2 + Cl + UV
CF2 + 2*Cl (cycle entry)
Cl + O3
ClO + O2
ClO + O3
ClO2 + O2
ClO2 + O3
ClO3 + O2
ClO3 + O3
ClO4 + O2
ClO4 + UV
Cl + 2*O2
2*Cl
Cl2 (cycle exit)
Note that, in the natural cycle, 4 O3 molecules will absorb up to 4 UV photons per iteration (slightly less in practice due to ozone's natural tendency to break down without help), whereas the chlorine radicals complete an entire iteration using only 1 UV photon. Even given that an O2 molecule can form two O3 molecules using the energy of a single UV photon, the chlorine still makes the O3 breakdown process ruthlessly more efficient.
I used to be skeptical of the CFCs => ozone depletion arguments, but over the last decade I have to say that the evidence is mounting in favor of the theory. Unless someone else can come up with an alternate mechanism, one as supported by the evidence as the CFC theory, I for one will presume that the CFC theory is, if not perfectly correct, then the best fit for the evidence that we have.
My kernel (stock 2.4.18) was compiled without a hiccup using GCC 3.1, and it's been running just fine for 3 weeks now. GCC 3.1 is a dream for everything except (a) C++ apps dependent on C++ libraries (a true bitch sometimes), and (b) software that depends too much on GCC 2.9x bugs (thankfully, such software is very rare).
My understanding of it is that the hackery required to access non-aligned data requires a substantial cost in terms of either silicon or performance, on any processor (including x86). The Alpha designers (and most RISC designers, for that matter) chose to leave it unimplemented in the hardware, leaving it to the compilers to align everything to the native word size like they should be doing anyway.
The "correct" response to that situation would be to store each byte in its own machine word. Yeah, that wastes a lot of memory, especially if you have a lot of boolean flags, but -- more often than not -- it's not nearly as expensive as the performance tradeoff, even if the memory is owned by a single thread. A lot of the comp.lang.c newbies (and a fair number of non-newbies) who first see automated alignment get confused and want to know how to pack their structs, not realizing that it will probably make their program run slower unless they are doing some very specific things (e.g. their code's performance is dominated by calls to memcpy(3)).
<anecdote>
I was diagnosed by a psychiatrist, a little over a year ago, with the non-hyperactive variant of ADD. In the last year, I've been a more productive programmer than ever before, and I'm actually on my way toward getting a real job based on my Linux networking knowledge.
The downside? I'll probably be stuck taking Adderall (dextroamphetamine, basically legal speed) for life if I want to keep my focus. For the last week, I've been going without in an attempt to wipe out my tolerance (FYI, take my advice and don't deviate at all from what the prescription says without first running it past your doctor, no matter how innocuous the change seems) and I've seen myself revert completely. It's been a very stark contrast between what I've considered "normal" for the last year versus what I'd considered "normal" before, and it makes me appreciate the reality of ADD that much more.
</anecdote>
...until the DVD CCA realizes that they will piss off the software industry, severely, if they succeed in their current line of litigation. If code is speech, then it can be copyrighted but the 1st Amendment applies; if code isn't speech, then the 1st Amendment doesn't apply but it can't be copyrighted. Ergo, if the DVD CCA wins, the U.S. government will have to stop prosecuting for those who infringe the "copyright" of software. You think Microsoft is pissed at Linux? Wait until Disney tries to hack their balls off! :-P
I, for one, agree on both points. While the movie was entertaining, the math was ridiculous. The "magic number" was arrived at by nothing more than wishful thinking that devolved into numerology. Worse, the actual number pi has very little to do with spirals, and certainly no more to do with spirals than e and i do, so the entire name of the movie is bogus. Pointing out the prevalence in nature of fractals, the Fibonacci sequence, or the Golden Ratio would have made the movie more plausible from a mathematical standpoint.
But, again, the movie was quite good, and the soundtrack was intriguing enough that I bought it almost right away, and I probably would have even if it hadn't included a track from my favorite group, Orbital. Too bad they didn't pick a different Orbital song; P.E.T.R.O.L. is OK but not really representative of their work.
Given that the government basically gave Turing three options:
... I can't say I wouldn't have done the same in his place, although I probably would have tried to immigrate to a more gay-friendly country first. It's really a shame, too, as some of his most brilliant work was in the latter part of his life.
Yup. For instance, Uranium 238 has a half-life of about 4 billion years, which means that a given quantity of U-238 is safer than the same quantity of just about any other radioactive isotope.
This part is incorrect. Pu is indeed a heavy metal, but it is almost completely insoluble in water (with a concentration expressed in parts per million). Another heavy metal is Bi (bismuth), the active ingredient in Pepto-Bismol. If Bi were water-soluble, Pepto-Bismol would be a deadly poison, as it is immediately right of Pb (lead) and two rows down from As (arsenic). (Bi also has the interesting distinction of being the heaviest element with at least one stable isotope.) In addition, Pu-239 (both the most common and the most stable Pu isotope) has a half-life on the order of 20,000 years, making it a rather "warm" isotope. To get a medically significant amount of Pu into your bloodstream by ingestion in a single incident, you would need to swallow a significant fraction of a kilogram of the metal, which would be more than enough to blast your intestinal epithelial cells with a strong alpha burst. The 100,000 year figure in the article takes into account (a) secondary radioactivity induced by the waste in the surrounding materials, and (b) the composition of the waste. Fission waste is a blend of many radioactive isotopes of widely varying half-lives: some "hot", some "warm", and some "cool".
If the U.S. bureaucracy would stop sheep-bleating and pull its collective head out of its ass and pay attention to ongoing fission research, they would find out that the Yucca Mountain project is totally unnecessary because the time it takes for fission waste to cool could be dramatically cut by re-"burning" the waste mixed in with fresh fuel, allowing the "warm" waste to become "hot", thus reducing the danger to a span of a mere century or two at most. They would also start the gears turning on building plants based on the fuel-pellet design operating in Europe, where an overheat of the (liquid metal) coolant causes the fission reaction to spontaneously stop without human intervention and without risk of hydrogen explosions, eliminating the most prominent dangers of traditional fission reactors.
Unfortunately, they're opposed to the former because it's the same process used to turn U-238 into Pu-239 in the first place, making it a "security risk" (Waste recycling is a security risk, but multiple tons of highly radioactive waste stored at a well-known location for 100,000 years isn't?), and they're opposed to the latter because the voting public is anti-nuclear-anything. (Better ban smoke detectors next, they use Americium created in fission reactors!)
Sigh
Actually, it's not the radioactivity of plutonium alone that makes it so lethal. It is a very powerful carcinogen because the body accumulates what it absorbs over long periods of time, although its near-insolubility in water reduces its effective toxicity to far below what many people believe. However, if it reaches the bloodstream, it accumulates in the bone marrow and in the liver, where it has a half-life of elimination of 70 and 35 years, respectively, and inhalation of fine Pu dust can cause significant alpha exposure in the ~500 days that it takes the lungs to eliminate it.
To put it simply, it's neither a massive threat nor a relatively benign substance, and it gets a lot more bad PR in the press than other, much more worthy, scapegoats.
A friend of mine came across a site describing how to uncap SURFboard modems. Being the inquisitive hacker-in-training that I am, I read through their instructions, theorized what was ACTUALLY happening (as opposed to what they SAID was happening), then launched Ethereal and confirmed it. I've made some further discoveries since, but I've since rebooted my modem (which wipes the uncap) because I have an ISP that gives very fair caps (we have a business connection, ~$80/mon, roughly 8Mbit down and 570Kbit up). Here are my discoveries:
Summary: Genuine, but not worth the risk.
True, cat vision isn't as spiffy as most people believe -- it's a simple tradeoff between rods (night vision) and cones (vivid color and sharp definition) -- but I believe that cat hearing would more than make up for it in the case of these frogs.
Interesting links, although I won't be holding my breath while the results are checked. As one physicist is quoted in the NYTimes article as saying, "You have to get down on all fours and claw through the details to see such a small effect." However, even if the results are accurate, it won't mean that Einstein's General Theory of Relativity will be tossed out the window like a used tissue.
Just as Newton's physics are mostly right, when restricted to the realms where they are applicable, Einstein's physics are accurate to such a degree that any new physics will only need to be dragged out for the realms where Einstein's physics are found to be inapplicable. The Standard Model of Physics can be summed up as "use Quantum Chromo Dynamics for the EM, weak, and strong forces; use General Relativity for the gravitational force". The incompatibility between GR and QCD is quite striking, but the candidates to replace the Standard Model seem well on their way to making GR's tensor calculus look like simple algebra, making it likely that GR will still be the theory of choice for situations where it is mostly right.
That's why I mentioned that c is the speed of light in a vacuum. The speed of light in a non-vacuum medium is slowed down, to c divided by the refractive index of the medium (1.33 for water, for instance). Basic optics, known well before Einstein's time.
Citations, please?
I'm not the one missing the obvious. Unfortunately, Slashdot won't let me draw some ASCII art to explain, but I'll try and describe it in terms that you'll understand... remember that airspeed is speed relative to the air, and that air is essentially stationary compared to the ground when you're talking about Mach speeds.
From the perspective of the SAM site, the plane is moving at speed Mach 2 angle 0 with respect to the ground, then launches a missle that quickly assumes a path in which it is traveling at speed Mach 5 angle 315, which happens to be perfectly aimed such that it will impact the SAM site.
From the perspective of the plane, the SAM site is zooming underneath at speed Mach 2 angle 180. It launches the missle (let's presume it's guided), then observes as the missle fires up and assumes a path of travel with speed Mach 3.57 angle 293.5. The missle looks like it will fall short, except that the SAM site rushes underneath the missle just in time to be hit. Stupid SAM site!
In the train example, we have a train traveling at speed 0.5c angle 0. You are standing on the train, and your friend is directly in front of the train by a safe enough distance that he'll be able to sidestep the train when it gets close. So, from your perspective, your friend is rushing toward you at speed 0.5c angle 180, and the beam of light is rushing away from you at speed c angle 0. What does your friend see? According to Newton's mechanics, he should see you rushing toward him at speed 0.5c angle 0, and the beam of light should be traveling at speed 1.5c angle 0 (simple trigonometry -- you add two vectors with the same angle by adding their magnitudes). In reality, as confirmed by countless experiments, the most famous of which are known as as the Michelson-Morley experiments, your friend perceives the beam of light as traveling at precisely c. If you fire a railgun from the train with a slug that travels at speed 0.5c angle 0 relative to you, then your friend will see the slug traveling toward him at speed 0.8c angle 0. These results have been confirmed by many, many experiments, so the burden of proof is on Einstein's doubters to show -- using repeatable and accurate experimental methods -- that an alternative explanation can exist. The physics department at the University of California at Riverside has an excellent site introducing physics, including these two pages that explain why the ether theory from the late 19th and early 20th centuries is thoroughly debunked and cannot be modified to fit the facts without becoming an unfalsifiable hypothesis (i.e. a matter of faith).
Again, see the above links for an explanation of why ether theory cannot be falsified if it is modified to be consistent with our existing knowledge.
The statement assumes that relativity is true, but it's a testable and falsifiable statement that, if it were false, should be trivial to debunk. Despite multitudes of measurements and experiments, especially by the people who passionately desired to show it to be false, that very statement has not been found untrue even once.
Yes and no. He understood math quite well, but due to dyslexia he couldn't deal very well with the rote memorization and mechanized learning required of him by the school system. He eventually learned to deal with it well enough to get excellent grades.
(Disclaimer: IANAP, although I'm enamoured with the topic.)
It's not just subatomic particles that slow down, which is Einstein's true stroke of brilliance. Einstein began down the road of Special Relativity by postulating that Newton's Principle of Relativity -- no matter where you are in the universe, the laws of physics are the same for all inertial (constant velocity) frames -- is correct. One of the laws of physics, courtesy of Maxwell's Equations, requires that the speed of light in a vacuum, c, is a constant. So, if both of these postulates are correct, then everyone will agree on the value of c in all inertial frames.
This deserves some illustration. Suppose you're on a hypothetical train traveling at a constant velocity of 0.5c towards a friend, and you point a flashlight straight forward and turn it on. You perceive the beam of light as traveling toward your friend at speed c; however, your friend sees the beam of light as traveling toward him at speed c, and not speed 1.5c. How can this be?
The answer that Einstein came up with, and the only known set of physical laws of motion that is consistent with both Maxwell's Equations and the Principle of Relativity, requires that your friend sees you as flowing through time at a slowed rate, whereas you see him as the one who is slowed down. With some extra geometry not far beyond a high school math student, it's not hard to prove that the length of (you|your friend) must contract; also, some modifications to Newton's Laws are required in order to make the laws of inertia and momentum self-consistent, making (you|your friend) appear to have more mass.
It is an inescapable conclusion of Special Relativity that the actual flow of time slows down -- General Relativity, the theory which tied SR and gravity together while introducing time as a 4th dimension, is not even required to prove this result. The very CRT that you're using to view this article right now could not possibly exist if Maxwell's Equations were grossly wrong, meaning the only way to prove SR grossly wrong about the flow of time would be to disprove the Principle of Relativity -- by demonstrating that the laws of physics vary depending on where you are in the Universe!
(A day late, a dollar short... I doubt anyone will read this. Oh well.)
I agree with Schneier that software liability is the only thing that can fix the sorry state of today's commercial software. I also agree with the Slashdotters who say that making authors of free (either meaning) liable would kill off the practice. When I first pondered this dilemma before, I came up with an idea so fiendishly perfect that I'm sure tons of people have thought of it before: make the degree of liability proportional to the cost of the software!
The Microsofts and Oracles of the world who make expensive, broken software will have to change one or the other or be sucked dry by damages awarded in liability lawsuits. On the flip side of the coin, the freeware and Open Source/Free Software communities won't have to change anything, and the shareware folks would be protected by the fact that most people who use their stuff never pay for it, perhaps even encouraging more people to buy shareware so that they might have legal recourse if it ever fails in the future.
Ah, Novell. Back in high school, all the PCs at our brand new "state of the art" school (the building was finished in 1994, and the PCs were 386DX/25's with 4MB RAM, IIRC, running MS-DOS, and were never upgraded once in 5 years -- don't let me get started on THAT rant) were sitting on a Novell network. Most of the network shares were read-only, but it seems that whenever the admin had trouble getting a new program running from the network, she would make its directory read-write.
The Pascal and AP Comp Sci classes had TONS of fun with a globally writable TURBOPAS directory; it started with everyone running the sample Breakout game, continued with some hacked-up source code mods, and eventually led to a ton of Pascal-written games and toys, including my own chat client. At the time I didn't know that Ralf Brown's Interrupt List existed, and only knew the barest of INT $10 and INT $21 calls, so I wrote it using a shared file to represent each "room" which each client would attempt to open and exclusively lock once per second, display any changes, and close. Scaled like shit, I imagine, but it was great fun once about 10-20 people had discovered it and were online at a time. (My /WHO command that turned student ID's into names was quite a shock to some of its abusers. :-P)
As others have pointed out, there is a difference between audio and data CDs. A Red Book CD-DA disc has sectors of 2352 bytes (1/75th of a second of audio), after the basic ECC is processed. A Yellow Book CD-ROM uses a second layer of ECC that turns those 2352-byte sectors into 2048-byte sectors, adding enough redundancy to deal with the fact that arbitrary data can't just be interpolated like audio can.
The Pons and Fleischmann experiment, if it had actually worked as well as they said it did, would have killed them from the neutron radiation. They didn't bother to do even the most basic accounting of what was going where and when, and they never compared what they measured to what they would have expected to see had they actually produced fusion. Worse, they hid details from their experiment for a considerable period of time, before saying "Wait, you weren't doing it right!" and giving the details of their palladium electrodes when the evidence was mounting against them.
The current experiment, even if it is wrong, at least was performed by experimenters who appear to understand the importance of collecting as much information as possible before hypothesizing models that explain it. The trouble with reproducibility might indicate a problem with their instrument calibration, plus the measured neutron flux and the detected tritium are in disagreement on how much fusion is taking place. However, at least the experimenters acknowledge this, and give a detailed enough description of their setup that others can try to reproduce it. It probably won't pan out, but I won't hold it against them.
If you like lpr/lpd, odds are that you'll adore LPRng. Throw together a handful of options in a pair of well-commented text config files, and you can set up ACLs, Kerberize everything, and not have a single program running as root or installed set[ug]id.
It's easy to deduce why DRM hardware that uses "positive" watermarking cannot possibly work in general. If the watermark is inaudible, then any decent lossy compression algorithm will remove it or scramble it beyond recognition. If the watermark is audible, people won't buy the music.
However, I can envision the nasty scenario where the DRM hardware refuses to play audio UNLESS it detects a valid watermark. Such "negative" watermarking has the actual potential to work, particularly if the watermark is used to encode a cryptographic signature of some digest that (A) can be generated algorithmically from the music and (B) is invariant to "reasonably" lossy compression. (Ssh! Don't tell the RIAA!)
My assumption has always been that they had enough very intelligent people (Carter, Daniel) in the team that the most important criteria for choosing a team leader was (a) someone who could think tactically on his/her feet, (b) able to command the people under him/her effectively, and (c) willing (even eager) to listen to the opinions of his teammates. That, combined with the fact that Jack and Daniel had worked together before and had a quirky understanding (in the Stargate movie) pretty much solidifed his place in the team.
It's not just women who find him attractive. :-) He puts off a very nice "I'm a geek, but I'll cuddle with you all night long" vibe (which I'm sure most of Slashdot doesn't need to know :-P). I'm mortified to hear that he's left the show (no Showtime, so I haven't been keeping up on SG-1), because he was my second favorite actor (after Amanda Tapping) and only by a slim margin.
I agree with his reason for leaving, tho -- weekly far-flung government conspiracies do NOT have a place in a show that's fundamentally about the joys (and terrors) of discovering the unknown.
I think it's the latter. The problem, IMHO, is that he's a pretty decent actor but is mediocre in at least some of the creative, behind-the-scenes stuff that he insists on doing. Because of his level of creative control on the show, he's one of few people who gets to write his own character. I think he's shooting for a realistic (in D&D terms) 10 INT 17 WIS character in his scriptwriting, but is too close to the character to spot the flaws in what he does.
I've been running the 2.4.13 Linus kernel on this system, and I have to say that it's the most stable 2.4.x kernel that I've tried. My uptime is currently 81 days and I have yet to tickle a bug. On my test box, I plan to try Marcelo's latest 2.4.x kernel out, but I had some bad experiences with .14 (the newest that I've tested).
According to those numbers, a $1500 T1 connection costs $1 per 1029.3333 bits/second of bandwidth, which equates to full utilization of 128kbit/s upstream costing $124.35. These numbers are horribly skewed, however, because (a) bandwidth is cheaper to your provider when they buy it in bulk (OC-3 lines and such); and (b) the costs of a T1 are wildly inflated already (See: regional monopoly).