One not so obvious fact is that the "target area" is approximately oval in shape. The landing area is pi*a*b where a and b are the major and minor radii of the oval. Thus the total area is approximately 3.141 * 35 * 22.5 = 2474 km^2.
The 1km dia crater has an area of 3.141 *.5^2 =.785 km^2
So.785 km^2 / 2474 km^2 =.000317 or.03%
So yeah, 2% doesn't look quite right on its face...
However, the target area is a probability distribution. The vehicle is not equally likely to touch down at all points within it. It's probably a 3-sigma target area distribution meaning you are something like 99.7% sure that the vehicle will impact within the target area, but points within 1-sigma of the target center are far more likely to be the touchdown points.
So, without knowing where the crater is in relation to the center of the touchdown spot, it is somewhat hard to say what proportion of the probability landing distribution it occupies. 2% could be an accurate probability if it is sufficiently close to the center of the target area.
the Pathfinder mission also used retrorockets to slow the decent, which the Beagle did not use. they felt that they could push the limits of heat braking and impact...on what basis????
Pathfinder used retrorockets when they were 80-100 meters above the surface and they fired for just a few seconds impart a very large force to the vehicle and particularly the tether connecting the rocket module to the lander. Pathfinder used retrorockets because they had to, not because they are more reliable.
Beagle, like Pathfinder, deployed a parachute after airbraking.
Parachute is the most reliable way to safely free descend from high altitude. The retrorockets or tether connecting the retrorockets on pathfinder were many times more likely to fail than the parachute, but also several times lighter than the additional parachutes that would have been required without the rockets.
If beagle was capable of landing with the parachutes and airbags then not using the retrorockets was the smart thing for them to do.
why take a chance when this is your first "real" mission and the whole world is watching???
Every space mission to date has been a calculated risk. They are all experimental, failure is a possibility that is accepted going in. If the benefits outweigh the risk, then you go for it. The benefits offered by beagle 2 (getting more quantitative research on the possibility of life on mars) outweighed the risk (you'll lose $40million bucks). The whole of the scientific community is, I hope, happy to see that the uk at least tried.
NOTHING was done until images of its landing position were sent, so that it would be known before hand if it had landed in an awkward position.
Good god, you don't even read your own supporting evidence. Let's see here:
If the lander comes to rest on its side, it will be righted by opening a side petal with a motor drive to place the lander in an upright position. Once upright, the other two petals are opened.
From an hour and a half before landing until about 3 and a half hours later, the spacecraft is under control of autonomous on-board software that precisely controls the many events that must occur.
Normal digital data transmissions will cease near the time of cruise stage separation due to the dynamics of EDL. Instead, the transmitter's carrier signal and sidebands will be recorded by the Deep Space Network's Madrid station so that the effects of the many events on the signal may be discerned. The digital data downlink will automatically resume 3.5 hours after landing, long after the airbags have been retracted and the petals opened.
Both pathfinder and beagle could right themselves if they came to rest on flat ground, regardless of their orientation.
The one-way travel time for the signal to reach Earth is 10 minutes 35 seconds.
Wow, so you know the one way travel time at the time when pathfinder landed. You know our two planets are orbitting the sun at different distances and angular velocities right? And the roundtrip time there is 21 minutes. I believe right now it is around 18 minutes, and since you are waiting for approval, it's the round trip time that matters.
As for the retrorockets... how much more massive was pathfinder than beagle 2? Using retrorockets makes things MORE complicated. It gives ONE MORE THING that could fail. If your mass is low enough that your drag chute alone will slow you to your safe impact speed, why would you complicate matters? Of course it doesn't really suprise me that things like reliability testing and notably physics escapes your grasp.
One could probably guess correctly that in its landing sequence configuration, the spacecraft does not have an antenna extended. The antenna would be no use during atmospheric insertion, or else catastrophically fail during impact. So until the spacecraft can get an antenna up, it isn't going to be talking with anybody. Thus it is a pretty small presumption that the vehicle itself will deal with issues of orientation and unfurling without consulting the orbiter or mission control 18 light minutes away.
design a half-assed re-entry method that is unproven
The Mars Pathfinder mission proved that a drag parachute plus impact absorbing air bag are effective mechanisms for touching down safely on mars.
without any type of backup.
What space vehicle to planetary atmospheric insertion system has ever been designed with a backup? When things go wrong during insertion, the result has always been loss of the vehicle. Even for vehicles whose precious cargo is living, breathing, humans.
This article is what you get when you give someone with no formal education in science and research undeserved attention. It's already well known that blue contributes very little to your perception of intensity, thus it is difficult to see detail in a blue image because it lacks contrast.
Are you talking about compression ratio or actual signal transmission power? It would seem strange for them to use a different frequency for each channel on a digital system. You'd think they'd get a couple high frequency slots and beam down multiple streams embedded in a single high bit rate feed. Now having finite bandwidth and compressing popular stuff less than unpopular stuff makes a bit more sense.
You are also paying for an battery installation. The rechargeable li-ion battery live inside the ipod. There is no little door you can open to swap the battery.
Sounds like bad engineering to me. Hence the reason the parent post was moderated "funny".
You have to open it up with an screwdriver to get to it, which most people are *not* willing to do. Not to mention voids the warranty.
The individual in the article was. Once the case was opened he was greeted by a mess of "sticky goo" (probably some sort of thermal grease). He attempted to follow the instructions, but killed the ipod in the process.
Li-ion batteries are also inherently *significantly* more expensive. They have about twice the power density of NiMH and have no "memory" issues at all. Unlike NiCD/NiMH batteries.
Yeah, my cell phone has a Li-Ion battery. Costs me an outrageous $40 for a new battery. Requires fully 10 seconds to replace the old battery. I can also get a battery with a vibrating attachment for when the ringer is off, or an extended life battery for when I know I'll be away from the recharger for a while.
$99 at apple would get me significantly less.
Their product has a design flaw. Are the new iPods coming with user-serviceable batteries?
128 bit encrypted WMA which they claim is "CD Quality."
Could someone give an objective description of what walmart is claiming to be "CD Quality". I am skeptical of both this and iTunes because I'm not going to pay a cent for something that sounds like a 128kbit mp3.
I'm just one of those freaks who can hear the difference between 128, 160, 192, 256 and 320 kbps mp3's, and I don't think anything less than 256 is worth spending a buck on (though judging by what I see on the file sharers, seems most people are perfectly happy with 128).
You call China terrible, yet deign to say anything about the state of foreign affairs in the country you want to be proud of.
At what point do YOU call something "terrible"? What's YOUR metric? Your ideals? Why aren't you calling the US terrible, then. Why aren't you calling Britain terrible?
SQ1.gif Shows people in the square beneath the (intact) statue of Saddam, but no tanks in the center itself. You cannot draw many inferences from this. Those could be plants and journalists. Could be Iraqi Saddam-haters. You just don't know.
SQ2.gif Shows a tank and several people in the square beneath the pedestal where the saddam statue once stood. The statue is no longer there. SQ2 was taken well after SQ1 as you can see from the amount of sunshine falling onto nearby buildings (like the mosque-looking building next to the square). In SQ1 there is no direct sunshine on any building. Tanks and humvees are visible surrounding the square..
SQ3.gif backs up in time to after the tank had arrived, but before anybody managed to climb to the top of the statue's pedestal. The resolution is too bad to tell who is a journalist, who is an Iraqi wanting to topple the statue, and who is just someone out to see the spectacle. Certainly some of the people seem to be standing as if they were journalists (honestly I can only find one who I am fairly certain is a photojournalist).
SQ4.gif shows a closeup of the statue with an American flag draped over Saddam's head and some Iraqi bystanders on the sidewalk across the street from the square.
I don't think these pictures tell a story different from what was broadcast around the world. I don't agree with information clearing house's interpretation of the facts. I see a group of Iraqi's who want to vandalize a statue which symbolized their oppression. The only possible media spin is crowd size. From these pictures the crowd looks to be in the 100-200 range. I think most people looking at the pictures would arrive at that number which is why the "they are clearly mostly journalists" argument comes up -- to downplay how many Iraqis might be there. However these pictures do not support that argument, the quality is simply inadequate to make such an inference.
I need better evidence to convince me that this was a staged scene.
If there was a human who decided something for a computer that was undecidable then how is that representable in a Turing machine?
I'm not sure I follow, but the answer I think is there was a stop symbol in the input (the user hitting ctrl-c to halt the machine).
The problem with user interaction is that a user can interrupt or alter the flow of the program... how is that represented in a Turing machine?
I think the issue is you're mixing when and how input comes in with the fact that it does. Regardless of when or how, the program is going to have to do some computation with it. The turing thesis says given the same input, a turing machine could be designed to implement the same algorithm and arrive at the same result. You might be confusing "the user just pressed the 'a' button" with "the input 'a' was provided". If the "when" is important, then that is an additional parameter of the input. If the "how" is important, that is one more parameter of the input.
It's sometimes difficult to equate the model with an actual CPU... after all, a CPU doesn't have to just write to memory, a CPU could write to an I/O port. If you view memory as your tape you may think this is a flaw in the model, that the CPU is more powerful than a Turing Machine. But this isn't so. Writing to an I/O Port is a form of output, the turing machine's tape is a generalization of input and output.
The presenter argued that no facility was present in a Turing Machine to represent a User interaction or user decision.
User interaction with a program is input into an algorithm. The difference between a computer program and a Turing Machine is the way in which that input enters the computation. In the Turing Machine, input exists on the tape before the machine begins execution. Using the "turing machine has no peripheral input" argument does not violate the the model.
This may seem strange if you aren't accustomed to an abstraction like this, but the claim is that if the same input is given to both the computer and the turing machine, there is no algorithm that can be done on the computer which cannot be done on the turing machine. How that input comes into existence (whether written onto the tape, or entered by a user) is irrelevant.
So my thinking was: If there is a set called Turing Computable... there is also a set that is Turing non-Computable. If user interaction is not in the set of things in the Turing Computable set AND modern computer programming languages can cope with some of this set... A language which expresses those Turing Non-Computable problems yet doesn't express the whole set of Turing Computable problems must exist.
That is a good start on the reasoning behind the computing theory. There is a set of problems which are Turing Non-Computable, the term commonly used is "undecidable".
The oft-used standard undecidable problem is the halting problem:
You would think that a very clever compiler could analyze the source code input and detect the existence of infinite loops (meaning the program being compiled would get into a state from which it would never halt). If such a compiler could be written, it could then be run on itself, and check to see if it would halt if given itself as input. You can prove that compiler cannot be written (it would halt if the answer was "it would not halt" - a contradiction). If you can write this compiler, get your application for grad school in now, you've got a great Ph.D. Thesis!
This is exactly the reason people should take an interest in mini-itx motherboards for home servers. A 60W power supply could feed one of the fanless 600MHz mini-itx boards at load. I don't have the means to measure, but I suspect at idle it runs around 15W (assuming the hard drive gets spun down during idle, which is not good for the lifetime of the drive, but good for power savings).
Turing Completeness doesn't really matter... a programming language has to beable to support the creation of Algorithms.
Oddly enough it can be shown that any programming language that is able to carry out some algorithmic computation is Turing Complete... And more oddly therefore a turing machine can carry out the same computation.
Since a turing machine is very, very simple, but just as powerful as any programming language at performing computation, it is useful as a way to measure whether or not something is a programming language. If the language is turing complete, it can carry out any computation any other turing complete language, or a turing machine, can. If I remember my computing theory correctly, there is no computable problem that cannot be solved by a turing machine but can be solved by some other means of computation, even non-deterministic methods computations.
However, it's largely impractical to make a turing machine for which you can say "Hey, watch this turing machine calculate the value for the pixel in the mandelbrot set centered at some arbitrary location given on the tape". It can, however, be done (though turing machines have no function called "WritePixel").
For hack value there are a couple programming languages that are turing complete and not much else. One is called "Brainf*ck" (with the * replaced by the vowel you may suspect) and the other called "Whitespace" (which I believe was an april fool's joke last year). People have, again just for hack value, written programs that perform some trivial task using these languages (mostly in Brainf*ck because white space is the single hardest language to read ever created).
That case would have a good chance of winning a summary judgement based on the merits of the case. The defendants would likely be able to ask for reimbursement of costs as part of that judgement.
Courts are starting to look unfavorably on frivolous DMCA claims, and the EFF is eager for more ammunition to show how bad this law really is for when it ends up in the supreme court (something you'll note the DMCA backers try rabidly to prevent).
For one, it was a very big enhancement. Also, there were several other enhancements along with my dual tuner capability that I enjoy.
What feature is it you miss so much? The only thing I missed was the backdoor, which was never an official feature anyway and is easily re-enabled with the tools available now.
My hacked Tivo does more than I ever expected it to, which is why I am under the reality distortion field. In addition to all the standard DVR stuff (and I think that recording two feeds simultaneously is a pretty cool standard feature) my Tivo can:
- Display closed captions on my old (but very reliable) sony tv. - Display caller id information on screen - Collect a caller id log and display it on screen. - Give me a local weather report on screen. - Show me a doppler radar image for my local weather on screen. - Accept programming information through the web (very useful for setting programs to record that you heard on the radio on your way to work) - Allow me to control the tivo through the web as if I had the remote (very useful if, like me, you have a toddler who occasionally "misplaces" the remote) - Send a quick message to my wife (if she's watching TV at the time)
None of those hacks are under attack by Tivo. It's no wonder the tivo hacking community is alive and fiercely loyal.
Of course I have some of the other hacks as well, allowing me to archive my favorite shows to inexpensive CDR instead of bulky and more expensive tapes.
Do you even remotely know what you are talking about?
How is that site's existence dependent on Tivo's goodwill not making a DMCA claim?? The tivo issues that could cause a claim are: Video Extraction, distributing OS images and service theft.
Every single one of those is a banned topic on the Tivo Community forums.
I do recall one of the forced upgrades enabled the second satellite tuner in my directivo allowing me to simultaneously record two programs while watching a third. Seemed like a clear feature enhancement to me.
Re:I think my form of encryption is better
on
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It is a good thing you were paying some attention in your stats class, but... This problem is not a selection without replacement. This problem is a selection with replacement. Thus A, B, C, D or E can occur in any of the five positions with equal probability. Thus, the proper combinatorics in this case is 5^5, or in the general case b^n. For a 2048 bit message it's 2^2048.
So to get message b from encrypted message c, you must try all possible bit patterns in a. You will get message b out of it, but you'll also get all possible messages of length |b|... One of those patterns probably contains the DeCSS source code and is therefore banned under pain of death or something.
They already tried that... dumped a million printed pages of Linux Kernel source on IBM's doorstep and said "It's in there!"
In this ruling the judge basically said "No really, where in there is it?" The 30 days part was also a smack down of SCO because a million printed pages is obviously a delaying tactic. It would have cost SCO far less to deliver a single CD-R. They have a phrase for it... "Malicious Compliance" or something like that -- You know where you pay a $2500 debt in pennies so that you greatly inconvenience the creditor - that kind of thing.
*sigh* slashdot trolls... It is not true that my right to shout "fire" in a crowded theatre hasn't been taken from me. Just as the analogy implies it is not true that the GPL doesn't force itself on code. In both cases the similarity was that it is preposterous to conclude that because you could always choose the option that would land you in court, you then have a choice and your freedom has not been curtailed.
If you're trying to say that different effective causes of two analogous items makes for a bad analogy, you'd be hard pressed to find a good analogy.
Popular analogies like "Love is like the tide, surging, ebbing and surging again" are bad analogies because the moon causes tides and love is subject to a persons fickle emotions?
Slashdot Mirror
One not so obvious fact is that the "target area" is approximately oval in shape. The landing area is pi*a*b where a and b are the major and minor radii of the oval. Thus the total area is approximately 3.141 * 35 * 22.5 = 2474 km^2.
.5^2 = .785 km^2
.785 km^2 / 2474 km^2 = .000317 or .03%
The 1km dia crater has an area of 3.141 *
So
So yeah, 2% doesn't look quite right on its face...
However, the target area is a probability distribution. The vehicle is not equally likely to touch down at all points within it. It's probably a 3-sigma target area distribution meaning you are something like 99.7% sure that the vehicle will impact within the target area, but points within 1-sigma of the target center are far more likely to be the touchdown points.
So, without knowing where the crater is in relation to the center of the touchdown spot, it is somewhat hard to say what proportion of the probability landing distribution it occupies. 2% could be an accurate probability if it is sufficiently close to the center of the target area.
the Pathfinder mission also used retrorockets to slow the decent, which the Beagle did not use. they felt that they could push the limits of heat braking and impact...on what basis????
Pathfinder used retrorockets when they were 80-100 meters above the surface and they fired for just a few seconds impart a very large force to the vehicle and particularly the tether connecting the rocket module to the lander. Pathfinder used retrorockets because they had to, not because they are more reliable.
Beagle, like Pathfinder, deployed a parachute after airbraking.
Parachute is the most reliable way to safely free descend from high altitude. The retrorockets or tether connecting the retrorockets on pathfinder were many times more likely to fail than the parachute, but also several times lighter than the additional parachutes that would have been required without the rockets.
If beagle was capable of landing with the parachutes and airbags then not using the retrorockets was the smart thing for them to do.
why take a chance when this is your first "real" mission and the whole world is watching???
Every space mission to date has been a calculated risk. They are all experimental, failure is a possibility that is accepted going in. If the benefits outweigh the risk, then you go for it. The benefits offered by beagle 2 (getting more quantitative research on the possibility of life on mars) outweighed the risk (you'll lose $40million bucks). The whole of the scientific community is, I hope, happy to see that the uk at least tried.
Good god, you don't even read your own supporting evidence. Let's see here:
Both pathfinder and beagle could right themselves if they came to rest on flat ground, regardless of their orientation.
The one-way travel time for the signal to reach Earth is 10 minutes 35 seconds.
Wow, so you know the one way travel time at the time when pathfinder landed. You know our two planets are orbitting the sun at different distances and angular velocities right? And the roundtrip time there is 21 minutes. I believe right now it is around 18 minutes, and since you are waiting for approval, it's the round trip time that matters.
As for the retrorockets... how much more massive was pathfinder than beagle 2? Using retrorockets makes things MORE complicated. It gives ONE MORE THING that could fail. If your mass is low enough that your drag chute alone will slow you to your safe impact speed, why would you complicate matters? Of course it doesn't really suprise me that things like reliability testing and notably physics escapes your grasp.
One could probably guess correctly that in its landing sequence configuration, the spacecraft does not have an antenna extended. The antenna would be no use during atmospheric insertion, or else catastrophically fail during impact. So until the spacecraft can get an antenna up, it isn't going to be talking with anybody. Thus it is a pretty small presumption that the vehicle itself will deal with issues of orientation and unfurling without consulting the orbiter or mission control 18 light minutes away.
design a half-assed re-entry method that is unproven
The Mars Pathfinder mission proved that a drag parachute plus impact absorbing air bag are effective mechanisms for touching down safely on mars.
without any type of backup.
What space vehicle to planetary atmospheric insertion system has ever been designed with a backup? When things go wrong during insertion, the result has always been loss of the vehicle. Even for vehicles whose precious cargo is living, breathing, humans.
I was trying to confuse the martians - star fleet regulations, ya' know :)
In 24th century Soviet Russia, Prime Directive violates YOU!
Yes, there is a reason for this... The blue-sensitive cones make up about 2% of the total cones in your eye.
However there is another significant aspect of blue. Because of the way the color sensitivity of your cones works, you are particular good at discriminating between different shades of blue.
This article is what you get when you give someone with no formal education in science and research undeserved attention. It's already well known that blue contributes very little to your perception of intensity, thus it is difficult to see detail in a blue image because it lacks contrast.
Are you talking about compression ratio or actual signal transmission power? It would seem strange for them to use a different frequency for each channel on a digital system. You'd think they'd get a couple high frequency slots and beam down multiple streams embedded in a single high bit rate feed. Now having finite bandwidth and compressing popular stuff less than unpopular stuff makes a bit more sense.
You are also paying for an battery installation. The rechargeable li-ion battery live inside the ipod. There is no little door you can open to swap the battery.
Sounds like bad engineering to me. Hence the reason the parent post was moderated "funny".
You have to open it up with an screwdriver to get to it, which most people are *not* willing to do. Not to mention voids the warranty.
The individual in the article was. Once the case was opened he was greeted by a mess of "sticky goo" (probably some sort of thermal grease). He attempted to follow the instructions, but killed the ipod in the process.
Li-ion batteries are also inherently *significantly* more expensive. They have about twice the power density of NiMH and have no "memory" issues at all. Unlike NiCD/NiMH batteries.
Yeah, my cell phone has a Li-Ion battery. Costs me an outrageous $40 for a new battery. Requires fully 10 seconds to replace the old battery. I can also get a battery with a vibrating attachment for when the ringer is off, or an extended life battery for when I know I'll be away from the recharger for a while.
$99 at apple would get me significantly less.
Their product has a design flaw. Are the new iPods coming with user-serviceable batteries?
128 bit encrypted WMA which they claim is "CD Quality."
Could someone give an objective description of what walmart is claiming to be "CD Quality". I am skeptical of both this and iTunes because I'm not going to pay a cent for something that sounds like a 128kbit mp3.
I'm just one of those freaks who can hear the difference between 128, 160, 192, 256 and 320 kbps mp3's, and I don't think anything less than 256 is worth spending a buck on (though judging by what I see on the file sharers, seems most people are perfectly happy with 128).
You call China terrible, yet deign to say anything about the state of foreign affairs in the country you want to be proud of.
At what point do YOU call something "terrible"? What's YOUR metric? Your ideals? Why aren't you calling the US terrible, then. Why aren't you calling Britain terrible?
Hmmmm, red herring and ad hominem tu quoque.
Troll elsewhere.
Your logic is truly illogical.
You are arguing that... media attention is the only true metric of "terrible"?
Huh?
Also, as an American, think of Panama, Iran contra, etc. Is the US any better?
So now by logical fallacy, Tibet isn't terrible?
SQ1.gif Shows people in the square beneath the (intact) statue of Saddam, but no tanks in the center itself. You cannot draw many inferences from this. Those could be plants and journalists. Could be Iraqi Saddam-haters. You just don't know.
SQ2.gif Shows a tank and several people in the square beneath the pedestal where the saddam statue once stood. The statue is no longer there. SQ2 was taken well after SQ1 as you can see from the amount of sunshine falling onto nearby buildings (like the mosque-looking building next to the square). In SQ1 there is no direct sunshine on any building. Tanks and humvees are visible surrounding the square..
SQ3.gif backs up in time to after the tank had arrived, but before anybody managed to climb to the top of the statue's pedestal. The resolution is too bad to tell who is a journalist, who is an Iraqi wanting to topple the statue, and who is just someone out to see the spectacle. Certainly some of the people seem to be standing as if they were journalists (honestly I can only find one who I am fairly certain is a photojournalist).
SQ4.gif shows a closeup of the statue with an American flag draped over Saddam's head and some Iraqi bystanders on the sidewalk across the street from the square.
I don't think these pictures tell a story different from what was broadcast around the world. I don't agree with information clearing house's interpretation of the facts. I see a group of Iraqi's who want to vandalize a statue which symbolized their oppression. The only possible media spin is crowd size. From these pictures the crowd looks to be in the 100-200 range. I think most people looking at the pictures would arrive at that number which is why the "they are clearly mostly journalists" argument comes up -- to downplay how many Iraqis might be there. However these pictures do not support that argument, the quality is simply inadequate to make such an inference.
I need better evidence to convince me that this was a staged scene.
It's not know that Iraq had supported any terrorist attack in the world.
So giving the families of palestinian suicide bombers $15,000 isn't supporting terrorism?
Please explain "terrible", "yet another free country", and "enslaved" please.
Tibet
If there was a human who decided something for a computer that was undecidable then how is that representable in a Turing machine?
I'm not sure I follow, but the answer I think is there was a stop symbol in the input (the user hitting ctrl-c to halt the machine).
The problem with user interaction is that a user can interrupt or alter the flow of the program... how is that represented in a Turing machine?
I think the issue is you're mixing when and how input comes in with the fact that it does. Regardless of when or how, the program is going to have to do some computation with it. The turing thesis says given the same input, a turing machine could be designed to implement the same algorithm and arrive at the same result. You might be confusing "the user just pressed the 'a' button" with "the input 'a' was provided". If the "when" is important, then that is an additional parameter of the input. If the "how" is important, that is one more parameter of the input.
It's sometimes difficult to equate the model with an actual CPU... after all, a CPU doesn't have to just write to memory, a CPU could write to an I/O port. If you view memory as your tape you may think this is a flaw in the model, that the CPU is more powerful than a Turing Machine. But this isn't so. Writing to an I/O Port is a form of output, the turing machine's tape is a generalization of input and output.
The presenter argued that no facility was present in a Turing Machine to represent a User interaction or user decision.
User interaction with a program is input into an algorithm. The difference between a computer program and a Turing Machine is the way in which that input enters the computation. In the Turing Machine, input exists on the tape before the machine begins execution. Using the "turing machine has no peripheral input" argument does not violate the the model.
This may seem strange if you aren't accustomed to an abstraction like this, but the claim is that if the same input is given to both the computer and the turing machine, there is no algorithm that can be done on the computer which cannot be done on the turing machine. How that input comes into existence (whether written onto the tape, or entered by a user) is irrelevant.
So my thinking was: If there is a set called Turing Computable... there is also a set that is Turing non-Computable. If user interaction is not in the set of things in the Turing Computable set AND modern computer programming languages can cope with some of this set... A language which expresses those Turing Non-Computable problems yet doesn't express the whole set of Turing Computable problems must exist.
That is a good start on the reasoning behind the computing theory. There is a set of problems which are Turing Non-Computable, the term commonly used is "undecidable".
The oft-used standard undecidable problem is the halting problem:
You would think that a very clever compiler could analyze the source code input and detect the existence of infinite loops (meaning the program being compiled would get into a state from which it would never halt). If such a compiler could be written, it could then be run on itself, and check to see if it would halt if given itself as input. You can prove that compiler cannot be written (it would halt if the answer was "it would not halt" - a contradiction). If you can write this compiler, get your application for grad school in now, you've got a great Ph.D. Thesis!
Slightly off topic, but...
This is exactly the reason people should take an interest in mini-itx motherboards for home servers. A 60W power supply could feed one of the fanless 600MHz mini-itx boards at load. I don't have the means to measure, but I suspect at idle it runs around 15W (assuming the hard drive gets spun down during idle, which is not good for the lifetime of the drive, but good for power savings).
Turing Completeness doesn't really matter... a programming language has to beable to support the creation of Algorithms.
Oddly enough it can be shown that any programming language that is able to carry out some algorithmic computation is Turing Complete... And more oddly therefore a turing machine can carry out the same computation.
Since a turing machine is very, very simple, but just as powerful as any programming language at performing computation, it is useful as a way to measure whether or not something is a programming language. If the language is turing complete, it can carry out any computation any other turing complete language, or a turing machine, can. If I remember my computing theory correctly, there is no computable problem that cannot be solved by a turing machine but can be solved by some other means of computation, even non-deterministic methods computations.
However, it's largely impractical to make a turing machine for which you can say "Hey, watch this turing machine calculate the value for the pixel in the mandelbrot set centered at some arbitrary location given on the tape". It can, however, be done (though turing machines have no function called "WritePixel").
For hack value there are a couple programming languages that are turing complete and not much else. One is called "Brainf*ck" (with the * replaced by the vowel you may suspect) and the other called "Whitespace" (which I believe was an april fool's joke last year). People have, again just for hack value, written programs that perform some trivial task using these languages (mostly in Brainf*ck because white space is the single hardest language to read ever created).
That case would have a good chance of winning a summary judgement based on the merits of the case. The defendants would likely be able to ask for reimbursement of costs as part of that judgement.
Courts are starting to look unfavorably on frivolous DMCA claims, and the EFF is eager for more ammunition to show how bad this law really is for when it ends up in the supreme court (something you'll note the DMCA backers try rabidly to prevent).
For one, it was a very big enhancement. Also, there were several other enhancements along with my dual tuner capability that I enjoy.
What feature is it you miss so much? The only thing I missed was the backdoor, which was never an official feature anyway and is easily re-enabled with the tools available now.
My hacked Tivo does more than I ever expected it to, which is why I am under the reality distortion field. In addition to all the standard DVR stuff (and I think that recording two feeds simultaneously is a pretty cool standard feature) my Tivo can:
- Display closed captions on my old (but very reliable) sony tv.
- Display caller id information on screen
- Collect a caller id log and display it on screen.
- Give me a local weather report on screen.
- Show me a doppler radar image for my local weather on screen.
- Accept programming information through the web (very useful for setting programs to record that you heard on the radio on your way to work)
- Allow me to control the tivo through the web as if I had the remote (very useful if, like me, you have a toddler who occasionally "misplaces" the remote)
- Send a quick message to my wife (if she's watching TV at the time)
None of those hacks are under attack by Tivo. It's no wonder the tivo hacking community is alive and fiercely loyal.
Of course I have some of the other hacks as well, allowing me to archive my favorite shows to inexpensive CDR instead of bulky and more expensive tapes.
Do you even remotely know what you are talking about?
How is that site's existence dependent on Tivo's goodwill not making a DMCA claim?? The tivo issues that could cause a claim are: Video Extraction, distributing OS images and service theft.
Every single one of those is a banned topic on the Tivo Community forums.
I do recall one of the forced upgrades enabled the second satellite tuner in my directivo allowing me to simultaneously record two programs while watching a third. Seemed like a clear feature enhancement to me.
It is a good thing you were paying some attention in your stats class, but... This problem is not a selection without replacement. This problem is a selection with replacement. Thus A, B, C, D or E can occur in any of the five positions with equal probability. Thus, the proper combinatorics in this case is 5^5, or in the general case b^n. For a 2048 bit message it's 2^2048.
So to get message b from encrypted message c, you must try all possible bit patterns in a. You will get message b out of it, but you'll also get all possible messages of length |b|... One of those patterns probably contains the DeCSS source code and is therefore banned under pain of death or something.
They already tried that... dumped a million printed pages of Linux Kernel source on IBM's doorstep and said "It's in there!"
In this ruling the judge basically said "No really, where in there is it?" The 30 days part was also a smack down of SCO because a million printed pages is obviously a delaying tactic. It would have cost SCO far less to deliver a single CD-R. They have a phrase for it... "Malicious Compliance" or something like that -- You know where you pay a $2500 debt in pennies so that you greatly inconvenience the creditor - that kind of thing.
*sigh* slashdot trolls... It is not true that my right to shout "fire" in a crowded theatre hasn't been taken from me. Just as the analogy implies it is not true that the GPL doesn't force itself on code. In both cases the similarity was that it is preposterous to conclude that because you could always choose the option that would land you in court, you then have a choice and your freedom has not been curtailed.
If you're trying to say that different effective causes of two analogous items makes for a bad analogy, you'd be hard pressed to find a good analogy.
Popular analogies like "Love is like the tide, surging, ebbing and surging again" are bad analogies because the moon causes tides and love is subject to a persons fickle emotions?