Question: at what level of vacuum does sound cease to propagate? I imagine "cease to propagate" might be subjective? Or perhaps there's a definite line like "when the mean free path of the gas molecules is large compared to the chamber dimensions" (a gas molecule hits the wall more often than it hits another gas molecule) (as in turbopumps, is that even correct?)... though what that would mean in outer space isn't clear to me.
Well said. I'm reminded of how my thinking on the subject of copyright
changed after reading Lawrence Lessig's "Free Culture". One of his examples
was that of a court case involving two farmers against an airline (or just a
pilot?). Before airplanes were common, the law held that if you owned land,
you also owned the air above it all the way to the heavens and beyond. The
farmers were angry that airplanes were flying low over their fields and scaring
their chickens, and used this law to sue the pilots. The judge recognized what
a mess things would be if every flight passed through hundreds of uniquely
owned zones, and ruled against the farmers. New technology doesn't always fit
into old laws.
I'd be willing to bet that the need to "have sex" or masturbate or
whatever, instilled through ages of evolution, is largely unrelated to
feelings of pleasure. Foreskin or no, the urge to reproduce is the
same. Pleasure is just icing on the cake.
At another government agency, everyone also has their own inkjet.
Sharing a printer is discouraged as it requires changing the computer's
cnofiguration (bad). Laser printers are discouraged because toner is
classified as hazardous waste while ink cartridges are not... (this is a
lab setting). US tax dollars at work.
Think of "file size" as a type of hash. You could use the file size as a document hash. It would, of course,
not be robust to attack, but it would be a convenient and fast way to answer the question "are these files the
same?". Rsync can be told to use file size to answer this question. To get back to the point, any hashing
algorithm takes a file of any size and creates a hash of (for the sake of argument) fixed size N. Whatever
properties of the file were used to come up with the hash is irrelevant. The pigeon hole principle demands that
there will be collisions because there are more "files of any size" than hashes of size N. A collision means that
whatever properties of the file were used in the algorithm to create the hash are identical in the two colliding
files, including file size if that property is included in the hash. Again, collisions are a given.
I once wondered if a [de]compression algorithm for, say, jpegs, could be made like this: given a hash, a file
size, and the fact that the resulting file must be a valid jpeg, decompress this into the right picture. I think
this is common mistake because it's difficult to comprehend the numbers involved. The requirement of being valid
jpeg file is just adding another property of the file into the hash. The pigeon hole principle always wins, and all
hashes squeeze A LOT of files into a drastically smaller space.
Saying things like "use MD5 and file size" or "use MD5 and SHA-1" don't really make much sense. Sure, one would
hope that the techniques used to actually find useful collisions would be confounded by this... but remember there
will always be collisions. A good hashing algorithm's only purpose is to ensure that these collisions can only be
found through brute force and not through some shortcut that allows one to create forgeries. If it's easy to find
MD5 collisions, then even if SHA-1 did not have weaknesses then finding such MD5 collisions would drastically reduce
the search space to find dual MD5 SHA-1 collisions possibly bringing a brute force attack into the realm of
possibility.
Long term viability? How do you think algae grows? By taking
carbon
dioxide out of the air (or out of a factory's waste stream).
Combusting the algae removes oxygen from the air and releases carbon
dioxide. The amount of oxygen required to combust the algae is the same
that the algae put into the atmosphere during its growth. The amount of
carbon dioxide released is the same as the algae removed from the
atmosphere during its growth. The net change is zero. The energy input
is the sun, and like almost everything, is a form of solar power.
So, yes, using this on a waste stream won't reduce the carbon dioxide
output (but if it reduces NO2 emissions, that would be
fantastic). But for long term viability, it seems like it would be
a renewable cycle.
On a related note, every global warming story talks about CO2 acting
as a greenhouse... Now, the earth is in an equilibrium with the sun,
absorbing energy on one side, and radiating an equal amount on the other
side. The input from the sun never changes, just the rate of radiation.
Slow down that rate with CO2, and the equilibrium temperature goes up
(global warming). My question: does the mere act of capturing solar
energy, either by solar power or algae power, and traping it on earth
for later use affect this equilibrium in the same way? If so, I would
think CO2 wouldn't be the only problem; we'd also have the
(unescapable?) problem of our increased energy usage traping more solar
energy on the earth...
My vaporware email client displays messages with visually distuinguishing marks. Imagine a zoomed out view with a rectangle representing each email. Many things could be varied such as position of the rectangle, color, border color, border style, shape, size, and many more. A clever email client could make it easy to identify messages at a glance. All messages from "bob" could have a few features always the same, so new messages from "bob" could be easily spotted. All messages from the "foobar" mailing list would be over to the right, reducing the need to have multiple mailboxes for sorting purposes.
I believe "MRI" (magnetic resonance imaging) was originally (and still is in science) called "NMR" (nuclear magnetic resonance) (or something, those acronym expansions might be a little off). Emotions are a big thing...
It's so obvious that the system degenerates into two parties, that I've begun to believe it was designed that way on purpose... I seem to recall reading that the goal was for the myriad of different opinions to work for compromise before the election, which would then only include the two major opinions that had already been shaken out. Thus, the government would spend time getting work done rather than bickering and trying to come to a compromise.
The current state of affairs is atrocious though. I feel so distant from any issue, and there seems to be little to no intellectual discussion about anything. Just name calling and left vs. right labeling. Certainly I could be a better citizen by making an effort to better informed, but the mainstream would remain horribly uninformed and vulnerable to advertising which makes it impossible to win a major election without millions of dollars and a reasonably pretty face.
My take on the "wasted" votes: no large election has ever come down to a single vote. As Florida proved, the counting mechanism even lacks sufficient resolution to notice a single vote. A single vote will not affect the election's outcome. Thus, vote for the candidate you like, and stop worrying about the guy you hate getting elected because you "wasted" your vote. Feel free to campaign against the hated candidate and tell your friends not to "waste" their votes, because you may affect a large enough sphere to matter. But when you're in the voting booth, you can only affect a single and utterly irrelevant vote.
In the ridiculously big picture, all energy is precious. We will all be long dead before the heat death of the Universe, but heat death will happen. There is a limit to the amount of useful work that can be done in the Universe. Why is it pragmatic to spend this precious energy duplicating effort creating software that has already been created (e.g. creating a free SCM to replace BitKeeper)? Why is it pragmatic to rediscover the knowledge locked up in the BitKeeper sourcecode when said knowledge already exists and could be known by all? Why is it not pragmatic to work for a world where such duplication of effort is unnecessary (e.g. a world of free software)?
And I'm only half-kidding. We've created a magical machine that, once constructed a first time, may be duplicated any number of times at no cost. And the first thing we do is throw that magic away...
Can one undo a commandline "rm" in OSX? Can one undo a "move to trash, empty trash" in OSX? An honest question; I don't know much about OSX. Or can search for "deleted but not yet overwritten files", and OSX makes an effort to overwrite oldest files first and only when necessary? (that would actually be pretty nice...)
How is this a design flaw? If you ask me, it is the command-line's greatest strength. You tell it to do something and it does it.
In a nutshell, humans mistakes are inevitable. The command line is like a mischievious genie, doing exactly what you asked for. A proper design takes human imperfection into account and never assumes the human always means exactly what she says.
Note that an annoying "are you sure?" command line is also improper design. Fairly obvious that, as it obnoxiously gets in the way.
Undo is a good thing. It is my opinion that a system designed with universal undo in mind would not find much that couldn't be undone, even rm -r/. Of course, Unix is not like this and so we must choose between the mischievious genie and the annoying questions that are soon ignored and thus less than useless.
I wish freshmeat or some of the other software aggregators had a place to somehow mark the coder(s)'s level of skill. I have a couple projects, but I am largely incompetant. They "work for me", and I release them because others may find them useful. I certainly put forth my best effort and take some pride from my work, but I wish there was a standard way to inform users that this is not professional quality. Or at least "I intend to take this projet to level (n)" or "this is it, take it or leave it".
I guess the distros do this to some extent, defaulting to "good" packages... But it certainly could be easier to obtain that information.
While I'm at it, it'd be nice if packages listings (e.g. apt-cache show) could show some more standard info about a package such as Interface: none, CLI, Curses, Gtk+, Gnome, KDE. Scanning through the long Depends: line is tedius. I guess that's the only example I have. I just can't stand the xprogram, kthis and gthat approach to naming... but I do appreciate knowing at a glace what sort of interface a program has.
Ah, but we evolved to run after food every day, and survive without when we couldn't catch it. Modern life has changed faster than evolution can keep up. We aren't made to sit in a cubicle all day. We aren't made to drive cars everywhere, or get a meal whenever we want it, or play video games after sitting in a classroom all day. Hence many problems from living a modern life; American obesity comes to mind.
So, you want multiple identical domains?... How do you know which one is the "right" one?
I don't know. If my bank advertises "mybank.com", I can trust I am entering personal info at the correct website (ignoring DNS cache poisoning) without needing to use a cumbersome IP address; score one for the current DNS. So, at some level, no I do not want one unique name resolving to multiple sites. It is notable that the trust comes not from any property of the DNS/TLD (other than uniqueness), but from out-of-band information (information distributed by the bank directly, which I trust).
At a different level, if I have no out-of-band information, I cannot know the correct domain. If I am trying to locate the website of SomeCompany, I might try somecompany.com. Or I'd use a search engine and maybe find "somecompany.com", "some-company.com", "somecompany-widgets.com", or "somecompany.co.uk". The DNS/TLD system offers miniscule help in finding the correct site.
If I want Bob Smith's phone number, I look him up in the phone book and maybe get 50 entries along with additional information to help me choose the correct one. There is no phone book for the Internet. DNS is too low level, and search engines are too broad. Perhaps search engines or some other service could offer a more narrow search intended to locate an official website given a name, and we could be rid of this mess of TLDs.
DNS is good at converting a unique word to an IP address, making it much much easier to remember a large number of domain names (compared with telephone numbers). DNS is not good at locating the previously unknown website of a given entity. The TLD smorgasbord seems to be a failed attempt to make DNS reveal more information than it is prepared to reveal.
Be an elitist if you like. I've said it before, but it's worth saying again: my telephone directory allows names with spaces, names with punctuation, and multiple entries with identical names.
It's not a question of a minimum of tech knowledge. It's a question of yet another system that forces humans to bend to the limitations of computers. Of course, computers are perfectly capable of achieving what the telephone directory has and much more which makes it all the more frustrating. It hasn't been done due to inertia, laziness, or things I just don't understand.
You're on 10, all the way up, all the way up... Where can you go from there? Nowhere. What we do, is if we need that extra push over the cliff... Eleven.
Slashdot Mirror
Question: at what level of vacuum does sound cease to propagate? I imagine "cease to propagate" might be subjective? Or perhaps there's a definite line like "when the mean free path of the gas molecules is large compared to the chamber dimensions" (a gas molecule hits the wall more often than it hits another gas molecule) (as in turbopumps, is that even correct?)... though what that would mean in outer space isn't clear to me.
I thought the shorter wires helped generate less heat? Maybe nog significantly, but this should help some.
Well said. I'm reminded of how my thinking on the subject of copyright changed after reading Lawrence Lessig's "Free Culture". One of his examples was that of a court case involving two farmers against an airline (or just a pilot?). Before airplanes were common, the law held that if you owned land, you also owned the air above it all the way to the heavens and beyond. The farmers were angry that airplanes were flying low over their fields and scaring their chickens, and used this law to sue the pilots. The judge recognized what a mess things would be if every flight passed through hundreds of uniquely owned zones, and ruled against the farmers. New technology doesn't always fit into old laws.
I'd be willing to bet that the need to "have sex" or masturbate or whatever, instilled through ages of evolution, is largely unrelated to feelings of pleasure. Foreskin or no, the urge to reproduce is the same. Pleasure is just icing on the cake.
At another government agency, everyone also has their own inkjet. Sharing a printer is discouraged as it requires changing the computer's cnofiguration (bad). Laser printers are discouraged because toner is classified as hazardous waste while ink cartridges are not... (this is a lab setting). US tax dollars at work.
Think of "file size" as a type of hash. You could use the file size as a document hash. It would, of course, not be robust to attack, but it would be a convenient and fast way to answer the question "are these files the same?". Rsync can be told to use file size to answer this question. To get back to the point, any hashing algorithm takes a file of any size and creates a hash of (for the sake of argument) fixed size N. Whatever properties of the file were used to come up with the hash is irrelevant. The pigeon hole principle demands that there will be collisions because there are more "files of any size" than hashes of size N. A collision means that whatever properties of the file were used in the algorithm to create the hash are identical in the two colliding files, including file size if that property is included in the hash. Again, collisions are a given.
I once wondered if a [de]compression algorithm for, say, jpegs, could be made like this: given a hash, a file size, and the fact that the resulting file must be a valid jpeg, decompress this into the right picture. I think this is common mistake because it's difficult to comprehend the numbers involved. The requirement of being valid jpeg file is just adding another property of the file into the hash. The pigeon hole principle always wins, and all hashes squeeze A LOT of files into a drastically smaller space.
Saying things like "use MD5 and file size" or "use MD5 and SHA-1" don't really make much sense. Sure, one would hope that the techniques used to actually find useful collisions would be confounded by this... but remember there will always be collisions. A good hashing algorithm's only purpose is to ensure that these collisions can only be found through brute force and not through some shortcut that allows one to create forgeries. If it's easy to find MD5 collisions, then even if SHA-1 did not have weaknesses then finding such MD5 collisions would drastically reduce the search space to find dual MD5 SHA-1 collisions possibly bringing a brute force attack into the realm of possibility.
Long term viability? How do you think algae grows? By taking carbon dioxide out of the air (or out of a factory's waste stream). Combusting the algae removes oxygen from the air and releases carbon dioxide. The amount of oxygen required to combust the algae is the same that the algae put into the atmosphere during its growth. The amount of carbon dioxide released is the same as the algae removed from the atmosphere during its growth. The net change is zero. The energy input is the sun, and like almost everything, is a form of solar power.
So, yes, using this on a waste stream won't reduce the carbon dioxide output (but if it reduces NO2 emissions, that would be fantastic). But for long term viability, it seems like it would be a renewable cycle.
On a related note, every global warming story talks about CO2 acting as a greenhouse... Now, the earth is in an equilibrium with the sun, absorbing energy on one side, and radiating an equal amount on the other side. The input from the sun never changes, just the rate of radiation. Slow down that rate with CO2, and the equilibrium temperature goes up (global warming). My question: does the mere act of capturing solar energy, either by solar power or algae power, and traping it on earth for later use affect this equilibrium in the same way? If so, I would think CO2 wouldn't be the only problem; we'd also have the (unescapable?) problem of our increased energy usage traping more solar energy on the earth...
Those poor contents... on the road to combustion. How sad.
My vaporware email client displays messages with visually distuinguishing marks. Imagine a zoomed out view with a rectangle representing each email. Many things could be varied such as position of the rectangle, color, border color, border style, shape, size, and many more. A clever email client could make it easy to identify messages at a glance. All messages from "bob" could have a few features always the same, so new messages from "bob" could be easily spotted. All messages from the "foobar" mailing list would be over to the right, reducing the need to have multiple mailboxes for sorting purposes.
Thanks for your links, they look interesting.
I believe "MRI" (magnetic resonance imaging) was originally (and still is in science) called "NMR" (nuclear magnetic resonance) (or something, those acronym expansions might be a little off). Emotions are a big thing...
Is it Bitch Checker or Bit ch-checker?
I tried to, but was shot down :(
Didn't Kerry receive something like the second largest amount of votes ever? The population is growing you know...
It's so obvious that the system degenerates into two parties, that I've begun to believe it was designed that way on purpose... I seem to recall reading that the goal was for the myriad of different opinions to work for compromise before the election, which would then only include the two major opinions that had already been shaken out. Thus, the government would spend time getting work done rather than bickering and trying to come to a compromise.
The current state of affairs is atrocious though. I feel so distant from any issue, and there seems to be little to no intellectual discussion about anything. Just name calling and left vs. right labeling. Certainly I could be a better citizen by making an effort to better informed, but the mainstream would remain horribly uninformed and vulnerable to advertising which makes it impossible to win a major election without millions of dollars and a reasonably pretty face.
My take on the "wasted" votes: no large election has ever come down to a single vote. As Florida proved, the counting mechanism even lacks sufficient resolution to notice a single vote. A single vote will not affect the election's outcome. Thus, vote for the candidate you like, and stop worrying about the guy you hate getting elected because you "wasted" your vote. Feel free to campaign against the hated candidate and tell your friends not to "waste" their votes, because you may affect a large enough sphere to matter. But when you're in the voting booth, you can only affect a single and utterly irrelevant vote.
In the ridiculously big picture, all energy is precious. We will all be long dead before the heat death of the Universe, but heat death will happen. There is a limit to the amount of useful work that can be done in the Universe. Why is it pragmatic to spend this precious energy duplicating effort creating software that has already been created (e.g. creating a free SCM to replace BitKeeper)? Why is it pragmatic to rediscover the knowledge locked up in the BitKeeper sourcecode when said knowledge already exists and could be known by all? Why is it not pragmatic to work for a world where such duplication of effort is unnecessary (e.g. a world of free software)?
And I'm only half-kidding. We've created a magical machine that, once constructed a first time, may be duplicated any number of times at no cost. And the first thing we do is throw that magic away...
Can one undo a commandline "rm" in OSX? Can one undo a "move to trash, empty trash" in OSX? An honest question; I don't know much about OSX. Or can search for "deleted but not yet overwritten files", and OSX makes an effort to overwrite oldest files first and only when necessary? (that would actually be pretty nice...)
How is this a design flaw? If you ask me, it is the command-line's greatest strength. You tell it to do something and it does it.
In a nutshell, humans mistakes are inevitable. The command line is like a mischievious genie, doing exactly what you asked for. A proper design takes human imperfection into account and never assumes the human always means exactly what she says.
Note that an annoying "are you sure?" command line is also improper design. Fairly obvious that, as it obnoxiously gets in the way.
Undo is a good thing. It is my opinion that a system designed with universal undo in mind would not find much that couldn't be undone, even rm -r /. Of course, Unix is not like this and so we must choose between the mischievious genie and the annoying questions that are soon ignored and thus less than useless.
I wish freshmeat or some of the other software aggregators had a place to somehow mark the coder(s)'s level of skill. I have a couple projects, but I am largely incompetant. They "work for me", and I release them because others may find them useful. I certainly put forth my best effort and take some pride from my work, but I wish there was a standard way to inform users that this is not professional quality. Or at least "I intend to take this projet to level (n)" or "this is it, take it or leave it".
I guess the distros do this to some extent, defaulting to "good" packages... But it certainly could be easier to obtain that information.
While I'm at it, it'd be nice if packages listings (e.g. apt-cache show) could show some more standard info about a package such as Interface: none, CLI, Curses, Gtk+, Gnome, KDE. Scanning through the long Depends: line is tedius. I guess that's the only example I have. I just can't stand the xprogram, kthis and gthat approach to naming... but I do appreciate knowing at a glace what sort of interface a program has.
Ah, but we evolved to run after food every day, and survive without when we couldn't catch it. Modern life has changed faster than evolution can keep up. We aren't made to sit in a cubicle all day. We aren't made to drive cars everywhere, or get a meal whenever we want it, or play video games after sitting in a classroom all day. Hence many problems from living a modern life; American obesity comes to mind.
So, you want multiple identical domains? ... How do you know which one is the "right" one?
I don't know. If my bank advertises "mybank.com", I can trust I am entering personal info at the correct website (ignoring DNS cache poisoning) without needing to use a cumbersome IP address; score one for the current DNS. So, at some level, no I do not want one unique name resolving to multiple sites. It is notable that the trust comes not from any property of the DNS/TLD (other than uniqueness), but from out-of-band information (information distributed by the bank directly, which I trust).
At a different level, if I have no out-of-band information, I cannot know the correct domain. If I am trying to locate the website of SomeCompany, I might try somecompany.com. Or I'd use a search engine and maybe find "somecompany.com", "some-company.com", "somecompany-widgets.com", or "somecompany.co.uk". The DNS/TLD system offers miniscule help in finding the correct site.
If I want Bob Smith's phone number, I look him up in the phone book and maybe get 50 entries along with additional information to help me choose the correct one. There is no phone book for the Internet. DNS is too low level, and search engines are too broad. Perhaps search engines or some other service could offer a more narrow search intended to locate an official website given a name, and we could be rid of this mess of TLDs.
DNS is good at converting a unique word to an IP address, making it much much easier to remember a large number of domain names (compared with telephone numbers). DNS is not good at locating the previously unknown website of a given entity. The TLD smorgasbord seems to be a failed attempt to make DNS reveal more information than it is prepared to reveal.
Be an elitist if you like. I've said it before, but it's worth saying again: my telephone directory allows names with spaces, names with punctuation, and multiple entries with identical names.
It's not a question of a minimum of tech knowledge. It's a question of yet another system that forces humans to bend to the limitations of computers. Of course, computers are perfectly capable of achieving what the telephone directory has and much more which makes it all the more frustrating. It hasn't been done due to inertia, laziness, or things I just don't understand.
If you got a ticket every time you sped, you would no longer speed, and the cash cow would be slain.
No. Do art forgeries "do"? If art experts can hardly tell the difference, why do so many people care?
You're on 10, all the way up, all the way up... Where can you go from there? Nowhere. What we do, is if we need that extra push over the cliff... Eleven.
Um, aren't they YCbCr?