Actually the parent comment is unintentionaly the key difference between windows and unix in my life. I use unix for everything until some idiot sends me a doc file.
[ please don't send me links to star office or abiword, or whatever. I'm glad they work for you but they don't for me. ]
I agree with Robert here, and give him full kudos on his work, and appriciate his clarifications. We should all support his work with MontaVista. I apologize as my comments were hastely put together and unfairly characterized this project (which I wholeheartedly think is cool!). I would agree that the kernel with this patch is preemptive (just not "fully" preemptive however). I realize after reading my original comments that I should have choosen some better wording! These guys have done some kick ass work, and I'm sure that it was a considerable amount of work.
The interrupt handlers can't allow premption during the context switch of an interrupt because the registers are intransit. Basically, you can't have an interrupt while your in the process of any kind of context switch otherwise you're never sure what registers you were able to flush to and from the CPU to the stack.
Critical Sections (such as access to the IP stack or I/O queues) have to be protected. With the advent of multi-processor systems under the SMP scheme, there is already considerable locking within the kernel to synchronize access of critical resources between processors. Critical regions also need to be protected from interrupt concurrent access as well.
Bottom Half handlers generaly are fast track implementations to quickly deal with the interrupts. To avoid concurrency collisions of reasources used within the bottom half handlers, interrupts (for that particular handler) must be disabled during the handler's execution.
All in all, this is basic non-preemptive stuff. What I don't understand is that this strategy that he is defining is a textbook NON-premtive approach to kernel design. I'm not too sure where he gets off claiming that the kernel is fully-preemptive here.
Yes, there is a new math. It's called Slashdalgerbra. Slashalgerbra has unique properties (mostly that are not inline with reality). When applied to accounting, Slashdalgerbra turns billions in loses into profits. When applied to software development, Slashalgerbra turns no intellectual property into patents and patents into public domain! When applied to age, Slashalgerbra always returns 13 years old. So of course with Slashalgerbra RAM is cheaper than HardDisk!
FaceRecog has 1 in 10,000 chance of giving a false-positive. That means that 1 in 10,000 times the machine will identify an innocent passanger as a terrorist.
Lets assume the FaceRecog shows 4 positive results for a single passanger manifest.
The odds that of those for each are innocent, or in otherwords that all 4 results are in fact false-positives are...
1 in (10,000 ^ 4).
I'll use a spell checker. You stay clear of Las Vegas.
You missed the basic premiss. In the WTC attacks there were 4 terrorists on a single plane. If the system were 1 in 10,000 accurate, that means that the odds that a 4 posatives results would occur on a single plane is 1 in (10,000 ^ 4) or 1 in 1,000,000,000,000.
...you need to continually worry about the integrity of the biometric database. What happens if someone is wrongfully included in the database?...
This applies to all forms of identification and identity databases. We have social security numbers and a social security credit database. The system has its occassional upsets, but all in all it works. The Police work with large criminal databases. etc. As a society we keep records of people. The security and integrity of those records has nothing to do with face recognition technology.
Terrorists are unlikely to pose for photo shoots.
Sure they are. We knew they were terrorists when they entered the country in the first place (which sparks an entirely different problem that I won't talk about). We have a passport photo which they posed for to get into the country. The fact is that we know who many of these people are. An internation database of known terrorists would work.
[ 99.99% accurate problem ]. Assume that one in one billion flyers, on average, is a terrorist. Is the software any good?
Damn right it is. The odds that 4 passangers on a single plane will be incorrectly identified as terrorists is roughly 1 in 1,000,000,000,000. Even if it is only one terrorist, a posative match might result in increased scrutiny of that individual. Such a screening tool could only be helpful.
The real problem with American Security systems is that idiots like this moron are advising people.
Sounds like a fancy passport. Gee wiz, nobody will ever be able to forge that! What a complete waste of time. Why anybody listens to that Jack Ass is beyond me. He's just panicing because nobody wants to pay $8,000/cpu for his shitty database anymore.
The US stock market was shut down for a record 6 days, all 250 million americans plus the 15-25 million foriegn visitors were prohibited from air travel. At least 40 billion dollars are going to be funnelled into rescue, relief, security and millitary operations in the short term, a great deal more in the long term. Plus, over 5,000 American civillians were killed. That's nearly 1/5th the number of U.S. millitary casualties during the Vietnam War.
The Rawandans were in Civil War with each other, not with Americans. Neither party in the Rawandan civil war tried to aquire nuclear and bioligical weapons of mass destruction for use against the United States.
AIDS is caused by a virus, not by mallicious, outspoken enemies of the U.S.
I too am reluctant to support dismantling of our civil liberties. However, I find your comparisions to be completely ludicrous.
No doubt. This study sounds like a bunch of crap. Of course, spending all of your weekend vegging on Quake is going to cause brain damage. However, spending all weakend playing thinking games like Warcraft, Sim*, etc, suring develops the brain evenly.
They said the same thing about dungeons and dragons back in the 80s. When I was 8 years old, the only books that I was reading with 400+ pages were the D&D manuals. It was a serious vocabulary lesson.
This agreement with the bond holders is going free up cash flow for Covad over the next year and at least give it a chance. The only people who get screwed here are the bond holders. However, they agreed to the deal (it wasn't shoved down their throats by the courts).
Do you find the Mundie debate remotely interesting?
Or, did you tire of this issue a long time ago realizing that debates are an irrelevant, waste of time and that people will do what is in their best interests regardless of what the academic and marketeers think?
Re:Who will win? Look at past years:
on
ICFP 2001 Task
·
· Score: 4
Thats because all of the good C engineers have jobs and are too busy to fsck around with stupid games like this. Caml programmers bored from a lack of any employment in the real world had no problem finding the time to dedicate to this problem.
What companies are calling for the restructuring of the internet? What a bunch of crap (typical of the LA Times). The internet is driven by the same economic principles that govern our highway system. Much of the internet transport falls under the domain of a public utility. Just like the highway system. Some private ventures get special access rights to set up profit making operations, like gas stations and fast food joints on a major interstate. The analogy that the internet pipe is dumb is flawed. The pipe is not dumb. The pipe routes packets in the best possible manner. However, the pipe doesn't know what is in the packets, just like the stop light doesn't know what is in your car.
You've just outlined the key note about Skycar: 12 years development == no usable product. What happened? I remember seeing the skycar on TV like 12 years ago and thought, "cool this will be out in a few years." Now, I see that nothing has happened. What is the story?
I always wondered about that movie. I had no idea what the hell was going on. I must have watched the censored version. Maybe I should get this DVD and give it a second chance.
Slashdot Mirror
// low budget version....
// TODO....
try {
--code--
} catch(exception e) {
throw e;
}
Don't go to MSN. What could possibly be of interest there?
Actually the parent comment is unintentionaly the key difference between windows and unix in my life. I use unix for everything until some idiot sends me a doc file.
[ please don't send me links to star office or abiword, or whatever. I'm glad they work for you but they don't for me. ]
I know this is flame, but do we really need to spend 5% of the federal budget on the space shuttle?
I agree with Robert here, and give him full kudos on his work, and appriciate his clarifications. We should all support his work with MontaVista. I apologize as my comments were hastely put together and unfairly characterized this project (which I wholeheartedly think is cool!). I would agree that the kernel with this patch is preemptive (just not "fully" preemptive however). I realize after reading my original comments that I should have choosen some better wording! These guys have done some kick ass work, and I'm sure that it was a considerable amount of work.
-Pete
The interrupt handlers can't allow premption during the context switch of an interrupt because the registers are intransit. Basically, you can't have an interrupt while your in the process of any kind of context switch otherwise you're never sure what registers you were able to flush to and from the CPU to the stack.
Critical Sections (such as access to the IP stack or I/O queues) have to be protected. With the advent of multi-processor systems under the SMP scheme, there is already considerable locking within the kernel to synchronize access of critical resources between processors. Critical regions also need to be protected from interrupt concurrent access as well.
Bottom Half handlers generaly are fast track implementations to quickly deal with the interrupts. To avoid concurrency collisions of reasources used within the bottom half handlers, interrupts (for that particular handler) must be disabled during the handler's execution.
All in all, this is basic non-preemptive stuff. What I don't understand is that this strategy that he is defining is a textbook NON-premtive approach to kernel design. I'm not too sure where he gets off claiming that the kernel is fully-preemptive here.
Yes, there is a new math. It's called Slashdalgerbra. Slashalgerbra has unique properties (mostly that are not inline with reality). When applied to accounting, Slashdalgerbra turns billions in loses into profits. When applied to software development, Slashalgerbra turns no intellectual property into patents and patents into public domain! When applied to age, Slashalgerbra always returns 13 years old. So of course with Slashalgerbra RAM is cheaper than HardDisk!
I'll put the nsync cd right with the star office 6.0b cd.
Is seems so unlikely that somebody would actually attempt to listen to an NSync albumn. Time to fsync nsync to /dev/null.
forgive me for the spelling.
lets talk statistics:
FaceRecog has 1 in 10,000 chance of giving a false-positive. That means that 1 in 10,000 times the machine will identify an innocent passanger as a terrorist.
Lets assume the FaceRecog shows 4 positive results for a single passanger manifest.
The odds that of those for each are innocent, or in otherwords that all 4 results are in fact false-positives are...
1 in (10,000 ^ 4).
I'll use a spell checker. You stay clear of Las Vegas.
You missed the basic premiss. In the WTC attacks there were 4 terrorists on a single plane. If the system were 1 in 10,000 accurate, that means that the odds that a 4 posatives results would occur on a single plane is 1 in (10,000 ^ 4) or 1 in 1,000,000,000,000.
This applies to all forms of identification and identity databases. We have social security numbers and a social security credit database. The system has its occassional upsets, but all in all it works. The Police work with large criminal databases. etc. As a society we keep records of people. The security and integrity of those records has nothing to do with face recognition technology.
Terrorists are unlikely to pose for photo shoots.
Sure they are. We knew they were terrorists when they entered the country in the first place (which sparks an entirely different problem that I won't talk about). We have a passport photo which they posed for to get into the country. The fact is that we know who many of these people are. An internation database of known terrorists would work.
[ 99.99% accurate problem ]. Assume that one in one billion flyers, on average, is a terrorist. Is the software any good?
Damn right it is. The odds that 4 passangers on a single plane will be incorrectly identified as terrorists is roughly 1 in 1,000,000,000,000. Even if it is only one terrorist, a posative match might result in increased scrutiny of that individual. Such a screening tool could only be helpful.
The real problem with American Security systems is that idiots like this moron are advising people.
Sounds like a fancy passport. Gee wiz, nobody will ever be able to forge that! What a complete waste of time. Why anybody listens to that Jack Ass is beyond me. He's just panicing because nobody wants to pay $8,000/cpu for his shitty database anymore.
Neee! Neeeeh! Neee NEeeeehh Niooo Neee neeeeh
What a piece of shit license. The free license is only for non-comercial use.
bad math, long day: 1/10th the number of US military casualties.
diffs:
The US stock market was shut down for a record 6 days, all 250 million americans plus the 15-25 million foriegn visitors were prohibited from air travel. At least 40 billion dollars are going to be funnelled into rescue, relief, security and millitary operations in the short term, a great deal more in the long term. Plus, over 5,000 American civillians were killed. That's nearly 1/5th the number of U.S. millitary casualties during the Vietnam War.
The Rawandans were in Civil War with each other, not with Americans. Neither party in the Rawandan civil war tried to aquire nuclear and bioligical weapons of mass destruction for use against the United States.
AIDS is caused by a virus, not by mallicious, outspoken enemies of the U.S.
I too am reluctant to support dismantling of our civil liberties. However, I find your comparisions to be completely ludicrous.
They said the same thing about dungeons and dragons back in the 80s. When I was 8 years old, the only books that I was reading with 400+ pages were the D&D manuals. It was a serious vocabulary lesson.
This agreement with the bond holders is going free up cash flow for Covad over the next year and at least give it a chance. The only people who get screwed here are the bond holders. However, they agreed to the deal (it wasn't shoved down their throats by the courts).
Do you find the Mundie debate remotely interesting?
Or, did you tire of this issue a long time ago realizing that debates are an irrelevant, waste of time and that people will do what is in their best interests regardless of what the academic and marketeers think?
Thats because all of the good C engineers have jobs and are too busy to fsck around with stupid games like this. Caml programmers bored from a lack of any employment in the real world had no problem finding the time to dedicate to this problem.
What companies are calling for the restructuring of the internet? What a bunch of crap (typical of the LA Times). The internet is driven by the same economic principles that govern our highway system. Much of the internet transport falls under the domain of a public utility. Just like the highway system. Some private ventures get special access rights to set up profit making operations, like gas stations and fast food joints on a major interstate. The analogy that the internet pipe is dumb is flawed. The pipe is not dumb. The pipe routes packets in the best possible manner. However, the pipe doesn't know what is in the packets, just like the stop light doesn't know what is in your car.
You've just outlined the key note about Skycar: 12 years development == no usable product. What happened? I remember seeing the skycar on TV like 12 years ago and thought, "cool this will be out in a few years." Now, I see that nothing has happened. What is the story?
I always wondered about that movie. I had no idea what the hell was going on. I must have watched the censored version. Maybe I should get this DVD and give it a second chance.