Most likely, this is part of the civil defense warning systems used for tornadoes, floods, mudslides, fires, etc. Somebody in local civil defense most likely got the idea to add Nuclear Missile Alert and the whole thing "mushroomed" into a mess.
Therac 25 teaches us that mechanical interlocks and switches are a good thing. The probability of failure of a well designed switch (1e-5 to 1e-6) is a lot lower and better analyzed than the probability of failure of half baked (or any kind of) software.
Making the final output of the system go through a mechanical switch for a real alert means that the system can't send a real alert without the switch being closed e.g. the signal path is physically open at the switch. P(false alert)=P(software fails)*P(switch fails)
If you feed the output of the switch through possibly defective software, you've changed the equation to P(failure)=P(software fails)+P(switch fails) which is similar to what caused the Challenger disaster.
In Challenger, the two seals on the booster rockets were deemed redundant with independent failure probabilities P(failure)=P(fail_seal1)*P(fail_seal2) however a common failure path for both seals,low temperature, was overlooked giving the equation as roughly P(failure)=P(fail_seal1)+P(fail_seal2).
Since the probability of the switch failing is near zero, with the switch in place as the sole last step, the chance of a false alert is near zero. If the switch is read by software then the chance of sending a false alert reverts to the failure percentage of the software negating the value of adding a switch to begin with .
When I was in semiconductor test, components were graded according to how well they met the spec and placed in bins. The lowest grade of component that vaguely worked even if it didn't meet the whole spec was colloquially known as the "Radio Shack Bin".
In a past life, I setup the free version of Alfresco for my teams. Configuration can be tough for those who don't like insanely deep trees of config files but it has a nice webdav server which integrates with the rest of it's quite awesome versioning capabilities. It's great for versioning anything that isn't source code.
I once wrote a program to extract video from an IRIG datastream while sitting in an aircraft hanger and trying to hear myself think over the electronics on an apache helicopter being run from ground power.
I actually found this story quite useful as the references it gave showed that some of the problems they solved are very similar to a research problem that I am working on in electron microscopy. That being said, the article was very technical and outside of my understanding in some of the more video game related areas. I'm happy to see this on slashdot.
The test they did suggested the snake's cross-sectional shape was more efficient than many other airfoil designs. This could have applications in aircraft design.
The Federal Law also allows state attorneys general to file suit on behalf of tax papyers in credit reporting cases. A local lawn care service accidentally submitted an already paid bill of mine to a collections agency. The Alabama Attorney General's Office was not amused and forced them to write a letter explaining themselves to me and then suggested that I sue the company which by then had seen the error in their ways.
In a Venture Capital funded startup, the VC puts up the original money. Taking the company public swaps the capital provided by the VC for capital provided by the public in the IPO. Publicly traded stock does little once the company is started unless new shares are issued after the company goes public.
AFAIK in some places in the U.S. there are laws that a corporation must send a corporate officer to answer a small claims case. This can be very painful for a large company.
I know exactly what you mean, metlin. I've been doing business case analysis for a startup I'm developing which will produce a tangible product with a high profit margin. A single machine in the production process has 6 zeroes in the price tag and the amount of money needed by the company over 5 years has seven zeroes. While I was able to fund the basic research with my own checkbook, scaling it into a profitable product with that funding source is impossible.
Honestly, some of the most interesting and intelligent people I have ever met were art historians. On the other hand, it isn't a degree you get as professional training to do something lucrative.
The XFS guys are right. I've lost data multiple times on XFS due to their disk caches being enabled in Suse 11.4. My disks are ST9750420AS using bios raid. I finally had to disable disk write caches on bootup. These losses were not even due to power failure: these losses were incurred during graceful system shutdown.
I do chemical engineering research in my spare time. I actually had to use calculus a few weeks ago to derive an equation for making a mixture of 2 solvents as similar as possible to the properties of a third solvent. For two solvents, the answer was a calculus gimme.
For three solvents, I had to break out multivariable calculus and Lagrange multipliers which didn't generate a solution but instead reduced the problem to a 4x4 matrix inversion. The inversion would have been most easily solved by feeding the matrix into the LAPACK library but a pedant could have solved it in his own code using Cramer's rule.
In my case, calculus wasn't enough, it only reduced the problem to linear algebra. Basically, you have to have taken enough math to recognize when you have transformed a problem form an intractable form to a tractable form.
Slashdot Mirror
Most likely, this is part of the civil defense warning systems used for tornadoes, floods, mudslides, fires, etc. Somebody in local civil defense most likely got the idea to add Nuclear Missile Alert and the whole thing "mushroomed" into a mess.
Therac 25 teaches us that mechanical interlocks and switches are a good thing. The probability of failure of a well designed switch (1e-5 to 1e-6) is a lot lower and better analyzed than the probability of failure of half baked (or any kind of) software.
Making the final output of the system go through a mechanical switch for a real alert means that the system can't send a real alert without the switch being closed e.g. the signal path is physically open at the switch. P(false alert)=P(software fails)*P(switch fails)
If you feed the output of the switch through possibly defective software, you've changed the equation to P(failure)=P(software fails)+P(switch fails) which is similar to what caused the Challenger disaster.
In Challenger, the two seals on the booster rockets were deemed redundant with independent failure probabilities P(failure)=P(fail_seal1)*P(fail_seal2) however a common failure path for both seals,low temperature, was overlooked giving the equation as roughly P(failure)=P(fail_seal1)+P(fail_seal2).
Since the probability of the switch failing is near zero, with the switch in place as the sole last step, the chance of a false alert is near zero. If the switch is read by software then the chance of sending a false alert reverts to the failure percentage of the software negating the value of adding a switch to begin with .
When I was in semiconductor test, components were graded according to how well they met the spec and placed in bins. The lowest grade of component that vaguely worked even if it didn't meet the whole spec was colloquially known as the "Radio Shack Bin".
In a past life, I setup the free version of Alfresco for my teams. Configuration can be tough for those who don't like insanely deep trees of config files but it has a nice webdav server which integrates with the rest of it's quite awesome versioning capabilities. It's great for versioning anything that isn't source code.
I once wrote a program to extract video from an IRIG datastream while sitting in an aircraft hanger and trying to hear myself think over the electronics on an apache helicopter being run from ground power.
See the author's photograph: http://onlinelibrary.wiley.com...
See: http://en.wikipedia.org/wiki/L...
I actually found this story quite useful as the references it gave showed that some of the problems they solved are very similar to a research problem that I am working on in electron microscopy. That being said, the article was very technical and outside of my understanding in some of the more video game related areas. I'm happy to see this on slashdot.
The test they did suggested the snake's cross-sectional shape was more efficient than many other airfoil designs. This could have applications in aircraft design.
The computer history museum in Mountain View, California has panels from the AN/USQ7 as well as the large lucite scale model of the building.
All of mine are Pickett. Note: Many of the modern tests and the EIT exam require a specific calculator model.
The Federal Law also allows state attorneys general to file suit on behalf of tax papyers in credit reporting cases. A local lawn care service accidentally submitted an already paid bill of mine to a collections agency. The Alabama Attorney General's Office was not amused and forced them to write a letter explaining themselves to me and then suggested that I sue the company which by then had seen the error in their ways.
There a re a lot of 501c3 organizations including universities that do a lot of work for profit.
In a Venture Capital funded startup, the VC puts up the original money. Taking the company public swaps the capital provided by the VC for capital provided by the public in the IPO. Publicly traded stock does little once the company is started unless new shares are issued after the company goes public.
AFAIK in some places in the U.S. there are laws that a corporation must send a corporate officer to answer a small claims case. This can be very painful for a large company.
Half inch mild steel might stop lead. Even .308 AP will go straight through without even slowing down. I have a whole box of such plates in my shop.
Wake me when it meets MILSTD 810-G.
I know exactly what you mean, metlin. I've been doing business case analysis for a startup I'm developing which will produce a tangible product with a high profit margin. A single machine in the production process has 6 zeroes in the price tag and the amount of money needed by the company over 5 years has seven zeroes. While I was able to fund the basic research with my own checkbook, scaling it into a profitable product with that funding source is impossible.
That failure pattern is called the bathtub curve or Weibull distribution.
Honestly, some of the most interesting and intelligent people I have ever met were art historians. On the other hand, it isn't a degree you get as professional training to do something lucrative.
The XFS guys are right. I've lost data multiple times on XFS due to their disk caches being enabled in Suse 11.4. My disks are ST9750420AS using bios raid. I finally had to disable disk write caches on bootup. These losses were not even due to power failure: these losses were incurred during graceful system shutdown.
A good use for stupidfilter http://stupidfilter.org/ perhaps?
Untar in this context simplym means heating up the sundial with a giant magnifying glass and hoping the tar runs off . .
It wasn't what they said but the aspersions in the way they said it that they made listening to them interesting. . .
I do chemical engineering research in my spare time. I actually had to use calculus a few weeks ago to derive an equation for making a mixture of 2 solvents as similar as possible to the properties of a third solvent. For two solvents, the answer was a calculus gimme.
For three solvents, I had to break out multivariable calculus and Lagrange multipliers which didn't generate a solution but instead reduced the problem to a 4x4 matrix inversion. The inversion would have been most easily solved by feeding the matrix into the LAPACK library but a pedant could have solved it in his own code using Cramer's rule.
In my case, calculus wasn't enough, it only reduced the problem to linear algebra. Basically, you have to have taken enough math to recognize when you have transformed a problem form an intractable form to a tractable form.