As far as I'm concerned, starting CS students with OO modeling is appropriate and I am disappointed in CMU in eliminating this from the freshman curriculum. Why? Because they need to start learning the discipline of thinking about computer constructs as things and not strictly abstractions. To think about how they are structured, behave, and interact
I guarantee you that with the freshman curriculum moving to include functional programming, the students will be thinking a lot more about structures and interaction than in any freshman-level OO course. You can't avoid thinking about it when you're programming in ML (which CMU uses for most of their functional stuff).
The world needs a lot more guys who can lay tile using best practice materials and approaches than the world needs guys in a lab trying to invent a better mortar
Sure, but that doesn't mean that MIT should gear its material science program toward the guys laying tile using best practices. CMU's one of the top 3 computer science programs in the country; their curriculum isn't geared toward turning out programmers.
I went to CMU. The curriculum is designed so that if you work hard, you can make it through the freshman courses without an incoming knowledge of programming; it's much, much easier if you know some basics coming in, but if you're motivated it's not necessary.
Moonraker was terrible, but Live and Let Die was awesome. Dalton's the only Bond who didn't have at least something to add to the role (even Lazenby was better than him).
I disagree; the last 10 years have pretty much been the golden years of TV. The Wire, Mad Men, Breaking Bad, the Sopranos, Deadwood, the Shield, Sons of Anarchy, Queer as Folk...even the step below that are still a ton better than most of what was on in the 70s, 80s, or 90s.
Hope that was a joke, because the US gov't doesn't get to copyright anything -- it's all public domain.
Works by the US government are only non-copyrightable domestically. They can certainly hold foreign copyright on them, which would apply to a Dutch radio geek.
There is a word "prepend" in both the OED and Merriam Webster's.
there is a specific meaning there that needs a word -- to append at the beginning
That's not what it means, though. It means premeditate--e.g. "he planned her murder with malice prepended". It's kind of a shame that computer science people co-opted an existing word rather than creating a new one, but it's not as though "prepend" in the dictionary sense was all that common.
Their work suggests that lining the rims of cans and bottles with a material similar to an ordinary coffee filter would be a simpler, cheaper alternative to the widget.
The good people at Guinness have already figured out the widgetless bottle; as of early this year, their draught bottles no longer contain a floating widget (at least in the US).
Yep. At 120 calories/12oz, Guinness is much closer to light beers (Bud Light is 110 calories/12oz) than to a standard Bud, Heineken, MGD, Coors, Corona or the like (generally in the 140-160 calories/12oz range).
I don't claim to be a chemist, but I don't think Guinness is carbonated. It uses nitrogen to make the little bubbles
Guinness is carbonated with CO2; it uses a nitrogen push.
The next time you're at a bar that has Guinness on tap, take a look at the taps--the Guinness tap is a tall, vertical faucet that has a restrictor plate in it. The purpose of that is to knock most of the CO2 out of solution quickly, to form the fine, cascading bubbles that Guinness is known for.
In order to push beer through the restrictor plate, you need a pretty high level of gas pressure to push it through. Normal beers just use CO2 to push them, but at the high pressures you need to drive a Guinness faucet you'd wind up with wildly overcarbonated beer (if you have a high pressure of CO2 in the keg, it will wind up overcarbonating the beer as it reaches equilibrium between the headspace in the keg and the dissolved volumes of CO2 in the beer).
The solution is to use high-pressure nitrogen to push the beer; nitrogen is basically insoluable in beer, so you don't wind up with the overcarbonation problem. Actually they use beergas, which is a blend of CO2 and nitrogen (if you had _no_ CO2, the beer would become undercarbonated as dissolved CO2 left solution to equalize pressure in the headspace).
The widgets that "draught" cans/bottles of Guinness use serve to agitate the beer quickly to force a portion of the CO2 out of solution quickly and form the microbubbles; it's still carbonated with CO2 in the cans and bottles, just as it is on tap.
hash tables are faster than B-trees for single lookups.
This depends on tons of factors. B-trees are almost invariably O(log n) unless they're totally braindead. Hash tables can be O(1) if they're perfect, but with a lot of collisions they can be O(n). And, of course, that's just the big-O; if the hash function is particularly slow then a single lookup could be a lot slower, even with better big-O performance.
And "for single lookups" is a big caveat; hash tables usually have terrible locality, which is something that B-trees are more optimized for.
I don't understand why any phone should be sending data (and wasting customers' money).
It shouldn't be wasting customer's money; the iPhone was designed to be used only with unlimited data plans (precisely so that Apple could have it do all kinds of "user-friendly" junk in the background without the customer paying for it), and for years after it was introduced you were required to have such a plan with it. AT&T moved that rug out from under it a year ago or so.
This does allow the current Pope no insignificant amount of power to try to direct the nature of his successor, but when the next Pope is chosen, he's dead.
He's out of office, not necessarily dead. There are precedents for papal resignation.
Second, we don't know whether factoring is NP-hard and it is conjectured not to be NP-hard (which does not mean we think it's polynomial!).
What other option is there? It's either polynomial (P) or not polynomial (NP), isn't it?
Being NP-Hard is a much higher bar than simply being in NP. A problem H is NP-hard if and only if there is an NP-complete problem L that is polynomial time Turing-reducible to H.
Or as Wiki puts it, "NP-hard (non-deterministic polynomial-time hard), in computational complexity theory, is a class of problems that are, informally, 'at least as hard as the hardest problems in NP'."
Burglary of a residence (where the Castle law might apply) in TN is Aggravated Burglary and carries a higher penalty. If anyone is injured (whether in a residence or not) it immediately escalates to Epecially Aggravated Burglary.
If committing an act that could lead to violence...has less penalty than one that only has economic impact, we have a problem in our system
As a general rule, to make that evaluation you have to determine the social damage of the violence vs. the economics. I'd definitely want Bernie Madoff punished more severely than someone who slapped a guy in the face at the bar.
Your argument is that: 1) "Unpaid overtime is a bad practice, but it's common in a lot of industries"
First, it's illegal. And second, "other people break the law" isn't an excuse. And third, whether it's common practice in some industries is unrelated to whether it's an honest business practice or not (which was the question at hand).
2) "Also, I don't give a rats ass if they employ illegal immigrants. In my opinion there should be no such thing as an illegal immigrant"
That's coherent, but also irrelevant as to whether they practiced honest business practices or not. Again "other people lie and cheat" isn't a defense against the assertion that you lie and cheat; it may impact how important we ultimately feel that honesty in business is, but it has nothing to do with whether Walmart practiced business honestly.
3) "Nor is it clear that it is an ongoing problem"
It's pretty clear to anyone who's bothered to spend a half hour researching it.
4) "The courts are the largest source of FUD on the planet"
I don't even know how to address this. Clearly the courts are not merely imperfect but often institutionally biased at best and arguably insane or malicious at worst. But if you actually believe they're "the largest source of FUD on the planet", I don't know what to tell you other than that a) you're incredibly naive; and b) I believe the burden of proof is clearly on you to back up this statement.
Most of the anti-walmart stuff you read is FUD, targated at them because they're the biggest retailer. And despite what everyone says, they got that way by having honest business practices
Forget random FUD for and against them and just look at what the courts have said. They've paid out hundreds of millions of dollars in class-action suits after it was found that the forced employees to work off the clock (see, for instance, http://www.usatoday.com/money/companies/management/2005-11-02-walmart-employees_x.htm "Wal-Mart, which earned $10 billion last year, agreed to pay $50 million in 2000 to settle a class-action lawsuit alleging that 69,000 former and current Wal-Mart employees in Colorado had been forced to work off the clock").
They've paid out millions of dollars in dozen of lawsuits over unfair practices with respect to hiring of disabled employees; they've been raided at least 3 different times for having scores of illegal immigrants working in their stores, and not just on an ad-hoc basis--the 2003 raid was of stores in over 20 different states with hundreds of workers involved (see http://money.cnn.com/2003/10/23/news/companies/walmart_worker_arrests/ which notes that "federal law enforcement officials said information from an undercover investigation revealed that some Wal-Mart executives and some store managers knew of the immigration violations.").
The problem is that there is no proof that what is in that paper can be made to hold for modern hard disk technology with vastly increased densities (SSDs and "secret" block remapping are another matter of course)..
Absolutely, hence my original caveat about modern denser drives (also discussed in Gutmann's epilogue).
The point about going to the moon is that it is that we know about it - it's "just" expensive. Recovering data on modern disks after zeroing is either currently so hard to do as to be impractical for more than a few bytes or someone is doing a fantastic job of keeping it quiet.
The former is another way of saying it's really expensive, no? I mean, you're basically reading bits one at a time off the platter; that's going to be incredibly painstaking and labor-intensive, hence pretty darned expensive--not something that you'd do for typical deleted files, but might be worth it if you think you have a disk that used to carry a billion dollar corporate trade secret or the plans to a massive terrorist attack or something like that.
Thus my comparison to the Mossad piecing together cross-shredded documents; it's something laborious (and therefore expensive) enough that it's not commercially viable, but that's different from saying it is--or was, on older, sparser drives--completely impossible.
Indeed, "Magnetic imaging on a spin-stand", Mayergoyz et al, Journal of Applied Physics, Volume 87, issue 9 includes small examples of imaging overwritten tracks (albeit with some misrepresentations), which are expanded upon in the authors' book "Spin-Stand Microscopy of Hard Disk Data"* Given that there exists limited success in a relatively unfunded academic paper, it'd be rash to believe that the approach is impossible for a well-funded determined attacker.
If that were real, there would be companies offering it as a service
We know that governments have reconstructed cross-shredded paper documents in the past; the fact that no company offers that as a service doesn't make it mythical. We know that NASA put people on the moon; the fact that no company offers trips to the moon as a current service doesn't mean it's not real. It just means it's too difficult and expensive to commercialize.
That something is feasible doesn't mean it's commercially viable. It requires fastidious efforts with a SFM or MFM electron microscope, and isn't likely to make a commercial appearance any time soon; at the same time, most governments won't allow declassification of any drive that had sensitive info on it even if it's overwritten many times (see the US government's guidelines on declassification of sensitive hardware for just one example).
But once that physical block is overwritten, the previous data is gone. Assertions to the contrary are nothing but urban legend and speculation. Nobody seems comfortable claiming that one pass with zeroes is sufficient, but I've seen no evidence that it isn't.
See Peter Gutmann's Secure Deletion of Data from Magnetic and Solid-State Memory from the 6th USENIX Security Symposium Proceedings, San Jose, California, July 22-25, 1996. It certainly surpasses the "urban legend" bar for me (it was peer-reviewed and academically vetted).
The whole paper is worth reading, and it certainly applies to hard drives and not cassettes or earlier meda. A relevant excerpt: The problem lies in the fact that when data is written to the medium, the write head sets the polarity of most, but not all, of the magnetic domains. This is partially due to the inability of the writing device to write in exactly the same location each time, and partially due to the variations in media sensitivity and field strength over time and among devices.
In conventional terms, when a one is written to disk the media records a one, and when a zero is written the media records a zero. However the actual effect is closer to obtaining a 0.95 when a zero is overwritten with a one, and a 1.05 when a one is overwritten with a one. Normal disk circuitry is set up so that both these values are read as ones, but using specialised circuitry it is possible to work out what previous "layers" contained. The recovery of at least one or two layers of overwritten data isn't too hard to perform by reading the signal from the analog head electronics with a high-quality digital sampling oscilloscope, downloading the sampled waveform to a PC, and analysing it in software to recover the previously recorded signal.
That said, Gutmann later proposed a 2-pass overwrite method that should be sufficient with modern drives, and offered a discussion of why some of the things proposed in the paper are less relevant on modern, denser hard drives than previously: http://www.forensicswiki.org/wiki/Epilogue_to_Gutmann's_1996_paper
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As far as I'm concerned, starting CS students with OO modeling is appropriate and I am disappointed in CMU in eliminating this from the freshman curriculum. Why? Because they need to start learning the discipline of thinking about computer constructs as things and not strictly abstractions. To think about how they are structured, behave, and interact
I guarantee you that with the freshman curriculum moving to include functional programming, the students will be thinking a lot more about structures and interaction than in any freshman-level OO course. You can't avoid thinking about it when you're programming in ML (which CMU uses for most of their functional stuff).
The world needs a lot more guys who can lay tile using best practice materials and approaches than the world needs guys in a lab trying to invent a better mortar
Sure, but that doesn't mean that MIT should gear its material science program toward the guys laying tile using best practices. CMU's one of the top 3 computer science programs in the country; their curriculum isn't geared toward turning out programmers.
I went to CMU. The curriculum is designed so that if you work hard, you can make it through the freshman courses without an incoming knowledge of programming; it's much, much easier if you know some basics coming in, but if you're motivated it's not necessary.
But Rome was also cancelled within 2 seasons, so it's not really a counterexample to the premise. Ditto John from Cincinnati.
Casino Royale (Daniel Craig) was darker and more brutal than On Her Majesty's Secret Service.
Moonraker was terrible, but Live and Let Die was awesome. Dalton's the only Bond who didn't have at least something to add to the role (even Lazenby was better than him).
I disagree; the last 10 years have pretty much been the golden years of TV. The Wire, Mad Men, Breaking Bad, the Sopranos, Deadwood, the Shield, Sons of Anarchy, Queer as Folk...even the step below that are still a ton better than most of what was on in the 70s, 80s, or 90s.
Hope that was a joke, because the US gov't doesn't get to copyright anything -- it's all public domain.
Works by the US government are only non-copyrightable domestically. They can certainly hold foreign copyright on them, which would apply to a Dutch radio geek.
"Prepend" isn't a word either
There is a word "prepend" in both the OED and Merriam Webster's.
there is a specific meaning there that needs a word -- to append at the beginning
That's not what it means, though. It means premeditate--e.g. "he planned her murder with malice prepended". It's kind of a shame that computer science people co-opted an existing word rather than creating a new one, but it's not as though "prepend" in the dictionary sense was all that common.
The good people at Guinness have already figured out the widgetless bottle; as of early this year, their draught bottles no longer contain a floating widget (at least in the US).
Yep. At 120 calories/12oz, Guinness is much closer to light beers (Bud Light is 110 calories/12oz) than to a standard Bud, Heineken, MGD, Coors, Corona or the like (generally in the 140-160 calories/12oz range).
I don't claim to be a chemist, but I don't think Guinness is carbonated. It uses nitrogen to make the little bubbles
Guinness is carbonated with CO2; it uses a nitrogen push.
The next time you're at a bar that has Guinness on tap, take a look at the taps--the Guinness tap is a tall, vertical faucet that has a restrictor plate in it. The purpose of that is to knock most of the CO2 out of solution quickly, to form the fine, cascading bubbles that Guinness is known for.
In order to push beer through the restrictor plate, you need a pretty high level of gas pressure to push it through. Normal beers just use CO2 to push them, but at the high pressures you need to drive a Guinness faucet you'd wind up with wildly overcarbonated beer (if you have a high pressure of CO2 in the keg, it will wind up overcarbonating the beer as it reaches equilibrium between the headspace in the keg and the dissolved volumes of CO2 in the beer).
The solution is to use high-pressure nitrogen to push the beer; nitrogen is basically insoluable in beer, so you don't wind up with the overcarbonation problem. Actually they use beergas, which is a blend of CO2 and nitrogen (if you had _no_ CO2, the beer would become undercarbonated as dissolved CO2 left solution to equalize pressure in the headspace).
The widgets that "draught" cans/bottles of Guinness use serve to agitate the beer quickly to force a portion of the CO2 out of solution quickly and form the microbubbles; it's still carbonated with CO2 in the cans and bottles, just as it is on tap.
For sure. Calling Solloway the Spam King is like calling Ladanian Tomlinson LT--there's already a well-established original with that nickname.
If P=NP, all modern encryption fails
If P=NP, most commonly used public-key encryption fails. Many symmetric key encryption algorithms remain safe (including one-time pads).
hash tables are faster than B-trees for single lookups.
This depends on tons of factors. B-trees are almost invariably O(log n) unless they're totally braindead. Hash tables can be O(1) if they're perfect, but with a lot of collisions they can be O(n). And, of course, that's just the big-O; if the hash function is particularly slow then a single lookup could be a lot slower, even with better big-O performance.
And "for single lookups" is a big caveat; hash tables usually have terrible locality, which is something that B-trees are more optimized for.
I don't understand why any phone should be sending data (and wasting customers' money).
It shouldn't be wasting customer's money; the iPhone was designed to be used only with unlimited data plans (precisely so that Apple could have it do all kinds of "user-friendly" junk in the background without the customer paying for it), and for years after it was introduced you were required to have such a plan with it. AT&T moved that rug out from under it a year ago or so.
This does allow the current Pope no insignificant amount of power to try to direct the nature of his successor, but when the next Pope is chosen, he's dead.
He's out of office, not necessarily dead. There are precedents for papal resignation.
Being NP-Hard is a much higher bar than simply being in NP. A problem H is NP-hard if and only if there is an NP-complete problem L that is polynomial time Turing-reducible to H.
Or as Wiki puts it, "NP-hard (non-deterministic polynomial-time hard), in computational complexity theory, is a class of problems that are, informally, 'at least as hard as the hardest problems in NP'."
Burglary of a residence (where the Castle law might apply) in TN is Aggravated Burglary and carries a higher penalty. If anyone is injured (whether in a residence or not) it immediately escalates to Epecially Aggravated Burglary.
If committing an act that could lead to violence ...has less penalty than one that only has economic impact, we have a problem in our system
As a general rule, to make that evaluation you have to determine the social damage of the violence vs. the economics. I'd definitely want Bernie Madoff punished more severely than someone who slapped a guy in the face at the bar.
Your argument is that:
1) "Unpaid overtime is a bad practice, but it's common in a lot of industries"
First, it's illegal. And second, "other people break the law" isn't an excuse. And third, whether it's common practice in some industries is unrelated to whether it's an honest business practice or not (which was the question at hand).
2) "Also, I don't give a rats ass if they employ illegal immigrants. In my opinion there should be no such thing as an illegal immigrant"
That's coherent, but also irrelevant as to whether they practiced honest business practices or not. Again "other people lie and cheat" isn't a defense against the assertion that you lie and cheat; it may impact how important we ultimately feel that honesty in business is, but it has nothing to do with whether Walmart practiced business honestly.
3) "Nor is it clear that it is an ongoing problem"
It's pretty clear to anyone who's bothered to spend a half hour researching it.
4) "The courts are the largest source of FUD on the planet"
I don't even know how to address this. Clearly the courts are not merely imperfect but often institutionally biased at best and arguably insane or malicious at worst. But if you actually believe they're "the largest source of FUD on the planet", I don't know what to tell you other than that a) you're incredibly naive; and b) I believe the burden of proof is clearly on you to back up this statement.
Most of the anti-walmart stuff you read is FUD, targated at them because they're the biggest retailer. And despite what everyone says, they got that way by having honest business practices
Forget random FUD for and against them and just look at what the courts have said. They've paid out hundreds of millions of dollars in class-action suits after it was found that the forced employees to work off the clock (see, for instance, http://www.usatoday.com/money/companies/management/2005-11-02-walmart-employees_x.htm "Wal-Mart, which earned $10 billion last year, agreed to pay $50 million in 2000 to settle a class-action lawsuit alleging that 69,000 former and current Wal-Mart employees in Colorado had been forced to work off the clock").
They've paid out millions of dollars in dozen of lawsuits over unfair practices with respect to hiring of disabled employees; they've been raided at least 3 different times for having scores of illegal immigrants working in their stores, and not just on an ad-hoc basis--the 2003 raid was of stores in over 20 different states with hundreds of workers involved (see http://money.cnn.com/2003/10/23/news/companies/walmart_worker_arrests/ which notes that "federal law enforcement officials said information from an undercover investigation revealed that some Wal-Mart executives and some store managers knew of the immigration violations.").
They're currently facing the biggest gender discrimination suit in US history--see http://money.cnn.com/2010/12/06/news/companies/Wal-mart-lawsuit-to-Supreme-Court/index.htm
So, yeah, "honest business practices".
The problem is that there is no proof that what is in that paper can be made to hold for modern hard disk technology with vastly increased densities (SSDs and "secret" block remapping are another matter of course)..
Absolutely, hence my original caveat about modern denser drives (also discussed in Gutmann's epilogue).
The point about going to the moon is that it is that we know about it - it's "just" expensive. Recovering data on modern disks after zeroing is either currently so hard to do as to be impractical for more than a few bytes or someone is doing a fantastic job of keeping it quiet.
The former is another way of saying it's really expensive, no? I mean, you're basically reading bits one at a time off the platter; that's going to be incredibly painstaking and labor-intensive, hence pretty darned expensive--not something that you'd do for typical deleted files, but might be worth it if you think you have a disk that used to carry a billion dollar corporate trade secret or the plans to a massive terrorist attack or something like that.
Thus my comparison to the Mossad piecing together cross-shredded documents; it's something laborious (and therefore expensive) enough that it's not commercially viable, but that's different from saying it is--or was, on older, sparser drives--completely impossible.
Indeed, "Magnetic imaging on a spin-stand", Mayergoyz et al, Journal of Applied Physics, Volume 87, issue 9 includes small examples of imaging overwritten tracks (albeit with some misrepresentations), which are expanded upon in the authors' book "Spin-Stand Microscopy of Hard Disk Data"* Given that there exists limited success in a relatively unfunded academic paper, it'd be rash to believe that the approach is impossible for a well-funded determined attacker.
* http://www.amazon.com/Spin-stand-Microscopy-Elsevier-Electromagnetism-ebook/dp/B000VHVGV4
If that were real, there would be companies offering it as a service
We know that governments have reconstructed cross-shredded paper documents in the past; the fact that no company offers that as a service doesn't make it mythical. We know that NASA put people on the moon; the fact that no company offers trips to the moon as a current service doesn't mean it's not real. It just means it's too difficult and expensive to commercialize.
That something is feasible doesn't mean it's commercially viable. It requires fastidious efforts with a SFM or MFM electron microscope, and isn't likely to make a commercial appearance any time soon; at the same time, most governments won't allow declassification of any drive that had sensitive info on it even if it's overwritten many times (see the US government's guidelines on declassification of sensitive hardware for just one example).
See Peter Gutmann's Secure Deletion of Data from Magnetic and Solid-State Memory from the 6th USENIX Security Symposium Proceedings, San Jose, California, July 22-25, 1996. It certainly surpasses the "urban legend" bar for me (it was peer-reviewed and academically vetted).
Available online here: http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html
The whole paper is worth reading, and it certainly applies to hard drives and not cassettes or earlier meda. A relevant excerpt:
The problem lies in the fact that when data is written to the medium, the write head sets the polarity of most, but not all, of the magnetic domains. This is partially due to the inability of the writing device to write in exactly the same location each time, and partially due to the variations in media sensitivity and field strength over time and among devices.
In conventional terms, when a one is written to disk the media records a one, and when a zero is written the media records a zero. However the actual effect is closer to obtaining a 0.95 when a zero is overwritten with a one, and a 1.05 when a one is overwritten with a one. Normal disk circuitry is set up so that both these values are read as ones, but using specialised circuitry it is possible to work out what previous "layers" contained. The recovery of at least one or two layers of overwritten data isn't too hard to perform by reading the signal from the analog head electronics with a high-quality digital sampling oscilloscope, downloading the sampled waveform to a PC, and analysing it in software to recover the previously recorded signal.
That said, Gutmann later proposed a 2-pass overwrite method that should be sufficient with modern drives, and offered a discussion of why some of the things proposed in the paper are less relevant on modern, denser hard drives than previously:
http://www.forensicswiki.org/wiki/Epilogue_to_Gutmann's_1996_paper
Also it helps you realize earlier if files are lost, which can be pretty important in some cases.