i actually do use netcat / telnet sometimes to hand-craft http-request in order to test security etc in scripts. It really *is* useful.
Re:Cha ching, reloaded.
on
Gates on Spam
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· Score: 1
There are all kinds of problems that are much harder to do in one direction than in the other.
yea, that's why asymetric (aka. public key) crypto works. More precisely, RSA works basically just like your riddle: take two large primes, multiply them together, hope that noone can figure out the factors from the product. I though everyone (at least on/.) would know that by now...
it's aptly called LinuxWiki. For now, (nearly) all articles are in german only, but they are going to change that. Maybe the people at LinuxQuestions.org would be interrested in some form of cooperation?
point taken. But i belive further thinking in that area could turn up a workable solution... i'll ponder that a little more... maybe working on a DOM and keeping track of changes as a history of operations would make this feasable. Then, the browser would receive a list of DOM-Operations (as JavaScript?) and would apply them dHTML-style. But that would require a major redesign on the server side. And it does not easily allow for personalized content. oh, well.
(man, i'm replying to an AC... get an account, seems like you've got something to say!)
...i use karamba also to show me a top,/var/log/messages, my inbox and a fortune... using the "program" sensor, you can get it to show almost anything on the desktop. Also, hacking that rss script gave me a reason to learn a little perl;)
BTW: I would really like a "ticker"-style text display in karamba. I tried to code it myself, but having never worked with qt and automake before, i'm having a dificult time to get that to compile...
When installing Karamba (KDE tool for putting dynamic content on the desktop), i noticed a perl script on the karamba homepage that would read a rss feed and display it on the desktop. I hacked it a little, to do nicer formating, read multiple feeds and handle different versions of rss, and now i have the headlines from/., kuro5hin, wired, the register and a few more on my desktop. Nice!
The i missed a way to klick on those headlines and open a browser -- karamba does not support stuff like that. So i hacked the script some more to write html to a file that i have open in my browser, updating automatically. In fact, i found this/. story this way....
why not introduce a new option into http, like modifications-since (similar to if-modified-since)? The server would return a "not modified" state if nothing was changed, and a diff (content-type=text/diff-script?) if there have been changes. For xhtml, this could even be done on a tag-by-tag basis, rather than line-by-line. Servers not supporting this option would just return the full page, or one could use if-modified-since as a fallback. Using the "Refresh" meta-tag, automatic updating every 60 secounds or such would be easy.
you can do this with (nearly) any language. Just write the code to a text-file, invoke the compiler and load the resulting library. Even without support for runtime-linked libs... self-modifying assembler, anyone?
Java is cool among the complied languages has it language-dynamic features that let you do lambda-like stuff (like inline-classes and proxy objects). It's a real pitty though that there is no (standard) api that you can give java-code (or bytecode, at that) and that would return a Class-object. Like a class called JavaCompiler, or such...
...but it's not very nice if you weld it into the system so it can't be removed or replaced (at least not without an awful lot of hacking). That is: open interfaces for system-plugins would be good. A multimedia-gui-monolith glued to the system is abusive.
Heisenbugs have another common cause: race conditions in multithreaded apps. Yea, sure, you *always* think of all the possibilites before-hand, create a state diagram and rule out all race conditions... yea, right.
I, for one, have come up with ony one way of dealing with those: use fewer threads. 3 is about the maximum number for pretty much any app i've ever written, and that includes the thread dispatching UI events. (and no, 1 is *not* enough).
man -k (or, if you have time, man -K) is rather handy... finds you a lot of stuff, though not everything. And google is your friend... (no, really!)
But having a book that baby-steps you through the basics will defenetly help. Well at least it'll help people who do not like to learn the "just let me play with that for a weak" way, which is legitimate(sp?) i think.
Ok now... first let me tell you that you happened to come across one of my pet peeves here. Please do not take it personally that i'm convinced you are missing a point here. I's actually a point that'S kind of hard to comprehend in a world where we are told about "hard science" all day. What i'm telling you is that the very basis of that "hard science" is to know what can't be known. That's what epistemology is all about -- try reading up on the subject: Keywords would be "Theory of Science" and "epistemology". A very important book in that regard is 'The Logic of Scientific Discovery' by Karl Popper (which i myself have only read in part). B. Russel is another famous name to be mentioned here, even if he was more concerned with (purely) mathematical proofs.
Now, let me answer some of your statements:
laws are correct within the constraints of the law
Depends on what you mean by "correct". A mathematical "proof" shows that some statement a follows neccessarily from a set of statements B. That's it. It does not tell us if the statements have anything to do with the "real" (i.e. observable) world.
The only way you can say a law is wrong is if: [...]
You are missing my point. I'm not saying math is "wrong". I would say it is consistent (and that is saying a lot). What i'm sayin is that we usually don't konw the "constraints" (i.e. the scope) of a "law" (i.e. a predictive model): 100 years ago most scientists would have said Newtons pysics is "correct": it is mathematically sound, and its predictions are very accurate compared with what we can observe. Then along came Einstein and told us that, when viewed on a larger scale, those predictions no longer hold. Far later, we even made observations that where indeed contrary to the laws of motion etc as proposed by Newton. Thus a "law" was overturned -- and this is possible for *any* law of physics (or any other empirical science that is build around modelling the observable world).
Laws are the absolute truth. At least, that's how you would view things if you follow the scientific path.
That's dead wrong. I would agree that there is such a thing as absolute mathematical truth -- but that's a truth stated inside a specific system about that system. Nothing is said about the observable ("real") world. In science dealing with modelling observable facts (like physics), you can't postulate an irrefutable statement: that is to say, any scientific statement must be able to be tested by experiment (irrefutable statements CAN NOT be tested by experiment -- that's a little tricky... think about it. Note that "irrefutable" means indead that there is no way (even in theory) to refute a statement -- it does not merely mean that the refuting outcome of the experiment will never occur). In short: irrefutable statements are scientifically meaningless (and rather hard to construct). Examples of irrefutable statements would be tautologies (like 1=1) and unknowables (like "there are things we will never know" itself).
But all laws ARE irrefutable facts. The reason is because they are mathematically proven.
No. The "laws" you are talking about are mathematically *deduced* from other statements (models), of which we can not know if they are "true" (i.e. if they yield correct predictions under ALL circumstances). None of the "laws" of physics can be mathematically derived from the rules of arithmetics (arithmetics and logic are just used to derive them from other statements, which assures their *consistency*, not their *truth*). Even the rules of arithmetics are build on axioms that we simply *belive* (see peano axioms).
But science IS mathematics
Again, no. Mathematics is a *tool* of science, and a very useful and powerful one. But most science is most definitely not mathematics.
You cannot have science without mathematics. Correct. Mathematics is what gives science its logical framework. Correct. Science is n
you are mistaking. "Laws" are just parts of theories that allow predictions. Laws are consideres valid as long as the observations are consistent with the predictions. You can not prove that a law is correct (how would you do that?), you can only a) (mathematically) show ("prove") that a low is *consistent* with some other law/theory -- you can not prove that it is "correct" as a representation of "reality" under all circumstances. You can only say that so far, we have not observed anything that violates a proposed law. In fact, manny of the "laws" of physics have already been shown to be not "entirely" true, i.e. the depend on surten simplifications: Conservation of Mass (and of Energy) for instance is only "correct" (i.e. consisten with observation), als long as we do not take into account the possibility of converting mass to energy (and vice versa), following the well known formula of E=MC^2: Atomic fission actually *destroys* mass. Now, folowing Einstein, we could say that the product of mass and energy in the universe is constant. But we can't be sure that that is really true -- we can only say that it "looks like that".
Again: a scientific statement is by definition a statement that could (in theory) be disproven by contrary observation. Stating an "irrefutable fact" is, again by definition, unscientific (see for a start the works of Karl Popper). Thus there is no absolute known "truth" in any science. All we can "prove" is the consistency of different sets of rules, according to yet another set of rules (arithmetics, logic, etc). That's where math comes in: in showing consistency. But it doesn't tell us anything about "reality".
Face it: science is not about "knowing what's really going on". It's just about producing "good guesses" about expected effects. Math is an exception here: it does not even try to tell us anything about reality, it works entirely on trying to show consequences and consistencies according to specific sets of rules and axioms (which are called "theories" or "calculus" (in the broader sense)).
People, please get that streight: In empirical science (that's pretty much any science besides math and philosophy), *nothing* can be proven. You can observe *evidence*, and can *disprove* a theory by providing contradicting evidence. But one can not prove a theory, by definition. You can show it's consitent with other theories. But you can't prove it has anything to do with *reality* (whatever that is). Teach your selfs some basic epistomology/phenomenology.
Ok. Now to black holes: IANAPhysicist, but as far as i know even though black holes can not be observed *directly* you can very well observe their effects like gravitational distortion, the radiation emitted by matter being sucked in, and according to S. Hawkings also a type a quantum radiation which causes black holes to evaporate over time (i'm not claimin i understood that).
As to the question of wether black holes are real? -- WE JUST DON'T KNOW. But i like the idea...;)
"It also includes a spectacular representation of the Internet"
hmmm... that represenation was taken from here, and its a snapshot from 1999 (sic). Also, i'v seen that before (aktually, i have one of those as a desktop image). I think it was on/. before...
are we being s^Htold old news? I mean, really old, not just your regular slashdot-dupes....
Also: look at theis galery of network images. Look at "Highschool Dating". Few cicles? No gays? something is wrong here... On the other hand, look at "Highschool Friendship": the four lonely ones to the left... what dot you think are the chances that thous four are still living in their parents basements and are reading slashdot?...
Is that only me, or does that sound a lot like TIA? Ask yourself the question: who will benefit from such a technology? Who has the reasources to employ it? The ones that come to my mind are the NSA, Time/Warner, Banks, etc. Is this really a good thing?
Let me quote Wau Holland on this one: "Wem gehoeren unsere Daten?" (engl.: "Who owns our data?") Who has what rights to process them, and in what ways? Do I have a say in what is done with "my" data (i.e. the data i "generate" just by being myself)?
Datamining is increasingly becoming an issue with respect to privacy (duh.) Is there anything that we meight do to stop this world from becoming a rather sophisticated version of 1984? Do i sound paranoid? Well, maybe i am. But i belive we also have to think about the implications of new "cool technology". Just going "oooohhh, something shiny" won't do in the long run.
Maybe that's because non of the city staff is using it yet? Remember, thei're still in the process of porting the applications that they need. Moving the users to a linux desktop will only be the last step.
Slashdot Mirror
what's that?
oh, wait...
you just made my day :-)
i actually do use netcat / telnet sometimes to hand-craft http-request in order to test security etc in scripts. It really *is* useful.
There are all kinds of problems that are much harder to do in one direction than in the other.
/.) would know that by now...
yea, that's why asymetric (aka. public key) crypto works. More precisely, RSA works basically just like your riddle: take two large primes, multiply them together, hope that noone can figure out the factors from the product. I though everyone (at least on
Educating users and fighting windmills feel about the same to me...
Oh, wait... windmills at least do not say "but i didn't *do* anything! really!"...
it's aptly called LinuxWiki. For now, (nearly) all articles are in german only, but they are going to change that. Maybe the people at LinuxQuestions.org would be interrested in some form of cooperation?
"Koala" is the name of the Java binding for KDE.
point taken. But i belive further thinking in that area could turn up a workable solution... i'll ponder that a little more... maybe working on a DOM and keeping track of changes as a history of operations would make this feasable. Then, the browser would receive a list of DOM-Operations (as JavaScript?) and would apply them dHTML-style. But that would require a major redesign on the server side. And it does not easily allow for personalized content. oh, well.
(man, i'm replying to an AC... get an account, seems like you've got something to say!)
...i use karamba also to show me a top, /var/log/messages, my inbox and a fortune... using the "program" sensor, you can get it to show almost anything on the desktop. Also, hacking that rss script gave me a reason to learn a little perl;)
BTW: I would really like a "ticker"-style text display in karamba. I tried to code it myself, but having never worked with qt and automake before, i'm having a dificult time to get that to compile...
When installing Karamba (KDE tool for putting dynamic content on the desktop), i noticed a perl script on the karamba homepage that would read a rss feed and display it on the desktop. I hacked it a little, to do nicer formating, read multiple feeds and handle different versions of rss, and now i have the headlines from /., kuro5hin, wired, the register and a few more on my desktop. Nice!
/. story this way....
The i missed a way to klick on those headlines and open a browser -- karamba does not support stuff like that. So i hacked the script some more to write html to a file that i have open in my browser, updating automatically. In fact, i found this
why not introduce a new option into http, like modifications-since (similar to if-modified-since)? The server would return a "not modified" state if nothing was changed, and a diff (content-type=text/diff-script?) if there have been changes. For xhtml, this could even be done on a tag-by-tag basis, rather than line-by-line. Servers not supporting this option would just return the full page, or one could use if-modified-since as a fallback. Using the "Refresh" meta-tag, automatic updating every 60 secounds or such would be easy.
yea, i think i would like that.
you can do this with (nearly) any language. Just write the code to a text-file, invoke the compiler and load the resulting library. Even without support for runtime-linked libs... self-modifying assembler, anyone?
Java is cool among the complied languages has it language-dynamic features that let you do lambda-like stuff (like inline-classes and proxy objects). It's a real pitty though that there is no (standard) api that you can give java-code (or bytecode, at that) and that would return a Class-object. Like a class called JavaCompiler, or such...
...no one in congress actually reads the laws s/he votes on.
...but it's not very nice if you weld it into the system so it can't be removed or replaced (at least not without an awful lot of hacking). That is: open interfaces for system-plugins would be good. A multimedia-gui-monolith glued to the system is abusive.
Heisenbugs have another common cause: race conditions in multithreaded apps. Yea, sure, you *always* think of all the possibilites before-hand, create a state diagram and rule out all race conditions... yea, right.
I, for one, have come up with ony one way of dealing with those: use fewer threads. 3 is about the maximum number for pretty much any app i've ever written, and that includes the thread dispatching UI events. (and no, 1 is *not* enough).
man -k (or, if you have time, man -K) is rather handy... finds you a lot of stuff, though not everything. And google is your friend... (no, really!)
But having a book that baby-steps you through the basics will defenetly help. Well at least it'll help people who do not like to learn the "just let me play with that for a weak" way, which is legitimate(sp?) i think.
...a rocket.
Ermmm... Mods on crack again?
Parent is possibly "funny", maybe "insightful", probably a "troll", but "informative"??? Informing you of what?
geeez...
Now, let me answer some of your statements:
laws are correct within the constraints of the law
Depends on what you mean by "correct". A mathematical "proof" shows that some statement a follows neccessarily from a set of statements B. That's it. It does not tell us if the statements have anything to do with the "real" (i.e. observable) world.
The only way you can say a law is wrong is if: [...]
You are missing my point. I'm not saying math is "wrong". I would say it is consistent (and that is saying a lot). What i'm sayin is that we usually don't konw the "constraints" (i.e. the scope) of a "law" (i.e. a predictive model): 100 years ago most scientists would have said Newtons pysics is "correct": it is mathematically sound, and its predictions are very accurate compared with what we can observe. Then along came Einstein and told us that, when viewed on a larger scale, those predictions no longer hold. Far later, we even made observations that where indeed contrary to the laws of motion etc as proposed by Newton. Thus a "law" was overturned -- and this is possible for *any* law of physics (or any other empirical science that is build around modelling the observable world).
Laws are the absolute truth. At least, that's how you would view things if you follow the scientific path.
That's dead wrong. I would agree that there is such a thing as absolute mathematical truth -- but that's a truth stated inside a specific system about that system. Nothing is said about the observable ("real") world. In science dealing with modelling observable facts (like physics), you can't postulate an irrefutable statement: that is to say, any scientific statement must be able to be tested by experiment (irrefutable statements CAN NOT be tested by experiment -- that's a little tricky... think about it. Note that "irrefutable" means indead that there is no way (even in theory) to refute a statement -- it does not merely mean that the refuting outcome of the experiment will never occur). In short: irrefutable statements are scientifically meaningless (and rather hard to construct). Examples of irrefutable statements would be tautologies (like 1=1) and unknowables (like "there are things we will never know" itself).
But all laws ARE irrefutable facts. The reason is because they are mathematically proven.
No. The "laws" you are talking about are mathematically *deduced* from other statements (models), of which we can not know if they are "true" (i.e. if they yield correct predictions under ALL circumstances). None of the "laws" of physics can be mathematically derived from the rules of arithmetics (arithmetics and logic are just used to derive them from other statements, which assures their *consistency*, not their *truth*). Even the rules of arithmetics are build on axioms that we simply *belive* (see peano axioms).
But science IS mathematics
Again, no. Mathematics is a *tool* of science, and a very useful and powerful one. But most science is most definitely not mathematics.
You cannot have science without mathematics. Correct. Mathematics is what gives science its logical framework. Correct. Science is n
you are mistaking. "Laws" are just parts of theories that allow predictions. Laws are consideres valid as long as the observations are consistent with the predictions. You can not prove that a law is correct (how would you do that?), you can only a) (mathematically) show ("prove") that a low is *consistent* with some other law/theory -- you can not prove that it is "correct" as a representation of "reality" under all circumstances. You can only say that so far, we have not observed anything that violates a proposed law. In fact, manny of the "laws" of physics have already been shown to be not "entirely" true, i.e. the depend on surten simplifications: Conservation of Mass (and of Energy) for instance is only "correct" (i.e. consisten with observation), als long as we do not take into account the possibility of converting mass to energy (and vice versa), following the well known formula of E=MC^2: Atomic fission actually *destroys* mass. Now, folowing Einstein, we could say that the product of mass and energy in the universe is constant. But we can't be sure that that is really true -- we can only say that it "looks like that".
Again: a scientific statement is by definition a statement that could (in theory) be disproven by contrary observation. Stating an "irrefutable fact" is, again by definition, unscientific (see for a start the works of Karl Popper). Thus there is no absolute known "truth" in any science. All we can "prove" is the consistency of different sets of rules, according to yet another set of rules (arithmetics, logic, etc). That's where math comes in: in showing consistency. But it doesn't tell us anything about "reality".
Face it: science is not about "knowing what's really going on". It's just about producing "good guesses" about expected effects. Math is an exception here: it does not even try to tell us anything about reality, it works entirely on trying to show consequences and consistencies according to specific sets of rules and axioms (which are called "theories" or "calculus" (in the broader sense)).
People, please get that streight: In empirical science (that's pretty much any science besides math and philosophy), *nothing* can be proven. You can observe *evidence*, and can *disprove* a theory by providing contradicting evidence. But one can not prove a theory, by definition. You can show it's consitent with other theories. But you can't prove it has anything to do with *reality* (whatever that is). Teach your selfs some basic epistomology/phenomenology.
Ok. Now to black holes: IANAPhysicist, but as far as i know even though black holes can not be observed *directly* you can very well observe their effects like gravitational distortion, the radiation emitted by matter being sucked in, and according to S. Hawkings also a type a quantum radiation which causes black holes to evaporate over time (i'm not claimin i understood that).
As to the question of wether black holes are real? -- WE JUST DON'T KNOW. But i like the idea...;)
end of rant.
"It also includes a spectacular representation of the Internet"
/. before...
hmmm... that represenation was taken from here, and its a snapshot from 1999 (sic). Also, i'v seen that before (aktually, i have one of those as a desktop image). I think it was on
are we being s^Htold old news? I mean, really old, not just your regular slashdot-dupes....
Also: look at theis galery of network images. Look at "Highschool Dating". Few cicles? No gays? something is wrong here... On the other hand, look at "Highschool Friendship": the four lonely ones to the left... what dot you think are the chances that thous four are still living in their parents basements and are reading slashdot?...
Is that only me, or does that sound a lot like TIA? Ask yourself the question: who will benefit from such a technology? Who has the reasources to employ it? The ones that come to my mind are the NSA, Time/Warner, Banks, etc. Is this really a good thing?
Let me quote Wau Holland on this one: "Wem gehoeren unsere Daten?" (engl.: "Who owns our data?") Who has what rights to process them, and in what ways? Do I have a say in what is done with "my" data (i.e. the data i "generate" just by being myself)?
Datamining is increasingly becoming an issue with respect to privacy (duh.) Is there anything that we meight do to stop this world from becoming a rather sophisticated version of 1984? Do i sound paranoid? Well, maybe i am. But i belive we also have to think about the implications of new "cool technology". Just going "oooohhh, something shiny" won't do in the long run.
penetrates the shield.
Maybe that's because non of the city staff is using it yet? Remember, thei're still in the process of porting the applications that they need. Moving the users to a linux desktop will only be the last step.