Remember Max Butler, aka Max Vision the guy the ran the whitehats website? He created a variant of a worm that attacked BIND, and had it patch the server. Unfortunately, he also introduced a backdoor.
Last I heard he is still in jail (I maybe wrong about this).
And yes, for a while it was common for a cracker to close the security hole while leaving a "secret" backdoor. Sometimes this was accomplished by placing a bogus entry in one's/etc/inetd.conf file; enter this port and gain/bin/sh with root priveleges. Word gets out (or a bunch of script kiddies are using the same exploit), and soon everybody notices strange packets trying to access some weird port.
In the Windows world there are a bunch of trojans ports (27374, 31337, etc...). Unfortunately the back door was open to everybody.
Don't worry? It doesn't affect everyday life? Are you crazy?
When Jerry Bruckheimer realizes that the Earth's magnetic field flips back and forth, he going to make a movie about this. You know, impending doom for all mankind, blah, blah, blah. The only way to stop this is to detonate a nuclear device. But it has to be at the core-mantle boundary! That's like 2900 km down! He'll try to get Bruce Willis to drill the hole, but Bruce's character is dead! So what will we get? Yup, Ben Affleck in the leading role! And he's got to drill 2900 km not some easy 800 ft. Do you realize how long the movie is going to be? With Affleck on the screen the entire time?
Then your wife or gf is going to say that you both have to see this latest movie with *sigh* Ben Affleck.
But if you know geophysics, you could tell her why the premise is total b.s. It may be the only way out of this bad situation.
Actually, the understanding that the Earth's magnetic field periodically switches polarity was known before the discovery of the magnetic stripes on the seafloor. Bruhnes, in 1906, put forth the hypothesis that there were reversals.
The precise dating of these reversal became practical in the late 1950's due to great advances in K-Ar dating techniques. There was then a big effort to map out this sequence in the 1960'. Coincidentally, the first series of "detailed" magnetic maps of the seafloor were also becoming available in the 60's. In 1963, Vine and Matthew published the seminal paper that hypothesized that the magnetic stripes on the seafloor were related to seafloor spreading and the magnetic field reversals.
In 1965 Vine and Wilson used the best known magnetic time scale to match the pattern of seafloor stripes on the Juan de Fuca Ridge (off Washington state). In doing so, they were the first to compute a spreading rate. Unfortunately, the best available time scale was missing a key reversal, and hence their match was incorrect. They discretely "fixed" this problem a couple of years later using a better magnetic time scale.
In SAIC's parlance, "Cyberpunkia" is the Metro stop on the blue line between Pentagon City and Arlington National Cemetary.
Another bit of trivia for those of you that visit DC. Prostitutes are easy to identify. They look just like well dressed business women except that they are wearing sneakers. Furthermore, there is free parking for Ryder rental vans on the 900 block of Pennsylvania Avenue, NW.
This is just a guess. Ultrasonic frequencies are greater than that that a human can hear. Higher frequencies also mean shorter wavelengths. This means that the sound source (e.g., transducer) can be equivalently smaller. One can then make a planar array of transducers that can be used to directional focus a beam of acoustic energy in a preferential azimuth. For instance, an Aegis cruiser's main radar array is a planar array.
But how does one then "hear" the signal in this directional acoustic signal. As others have pointed out there is something called the beating frequency when two signals interact. I would therefore have to surmise that the array contains two sets of arrays to transmit two different signals/ultrasonic frequencies. This might explain why he has problems at lower frequencies. The signals need to be closer in their frequency signal, which will also cause problems in the directional beam-forming.
Wish I could think about this a bit more, but I have to print a bunch of stuff right now.
Seminal. Seminal. Seminal. As in the original seed the begot, another, that begot another.
BTW, I only own two C books; note own. K&R 1st and 2nd Editions. Needed the latter one to get up to speed on the ANSI stuff. K&R is terse and does not have a lot of hand-holding examples. However, it did convert this FORTRAN progammer, non-CS major over to C in quick, efficient manner.
I must admit that K&R may not be very "practical" for someone without any programming experience. However, it is seminal.
I have to agree that a bit (a lot?) of what Spafford wrote was a bit over the top. My favorite could have been written by somebody on/.
"The next generation of Navy aircraft carriers is going to have all weapons systems, propulsion, and command and control run by the very same system that you use at home to browse the Internet and play computer games. This is the same one that keeps coming up with "blue screens of death," which take on new, grim meaning in a military environment."
If Spafford had been a bit more toned down, he could have still made the same points without introducing vulnerabilies in his arguments that would make one cringe. OTOH, his points should be contemplated and analyzed. Computer/network security is pathetic if one considers the worse case scenario. A design error that is inherent in a commonly used protocol used by network routers could potentiall create havoc. Hmmm, didn't we come close to this one?
The role that DARPA played in the "early" days of computing is often overlooked. DARPA funded the initial prototype development of something called the Stanford University Network workstation. IIRC, a guy by the name of Joy at UCB also received DARPA funding to enhance some of the capabilites of a "new" OS called UNIX. Eventually, the two efforts joined forces and produced a commercial product.
RISC technology was pushed forward by DARPA. One effort eventually led to MIPS. Another effort led to the development of the RISC I and RISC II. This technology was licenced to Sun Microsystems, and eventually evolved into a more scalable architecture. I believe that this had some modest commercial success.
Warp and the Connection Machine were the result of DARPA funded efforts to push forward and test the capabilites of massively parallel computers. These were technnological wonders, but did not achieve commercial success. At least, one of these was featured in a very successful motion picture. Furthermore, thanks to MIPS, probably the geekiest line in motion picture history was spoken, "This is a UNIX system. I know this."
I would also have to speculate that a there are numerous computer industry leaders that had RA's in grad school via DARPA funding.
I good indication of how far AI has advanced is the fact that GRACE is a brunette and not a blonde. In the next major advance, GRACE will don glasses and be renamed VELMA.
In unrelated news, the Big Five auditing firm Arthur Andersen today announced that they have decided to increase the number of job placement interviews at Princeton University in the upcoming year. A spokeperson for Arthur Andersen said that the academic and social environment at Princeton helps to produce the type of high quality people that they desired for their firm.
Rental car companies in the United Arab Emirates don't need this black box. Foreign visitors just need to read this little blurb from the US State Dept web site.
Country-wide traffic laws impose stringent penalties for certain violations, particularly driving under the influence of alcohol. Penalties may include hefty jail sentences and fines, and, for Muslims, lashings. Persons involved in an accident in which another party is injured automatically go to jail until the injured person is released from the hospital. Should a person die in a traffic accident, the driver of the other car is liable for payment of compensation for the death (known as "dhiyya"), usually the equivalent of 41,000 U.S. dollars. Even relatively minor accidents may result in lengthy proceedings, during which both drivers may be prohibited from leaving the country.
I believe this policy also pertains to a foreign passenger in a taxi. I was told that part of the logic behind this is that the accident would not have taken place if the foreigner was not in the country. Obviously I didn't rent a car while I was there, and I closed my eyes and prayed (to Allah, Jesus, RMS, Buddha, the Big Kahuna, Chucky Cheese, etc...) when I was in a taxi.
12 cm must refer to the floppy disk version, while 12 inches is the hard disk.:-) Quite impressive. If they were marketing this product towards women they could nickname it Magic Johnson. Unfortunately, I believe that John Wayne Bobbitt already has dibs on this nick.
In related news, Pentagon officials at a hastily called press conference announced a successful test of the National Missile Defense system. The scheduling of this test was not publicized in advance due to concerns about terrorism. An anonymous DoD source stated that, "Ahhh, that was our test. We finally got it to work. No wait, in fact we have had many successful secret tests. Yeah, that's the ticket!"
The only study that I will believe is one that make a positive correlation between playing video games and a decrease in one's ability to spell correctly.
This study would then be followed by one involving video games and grammar.
Absorption? Don't you mean geometrical spreading loss? The inverse-square relationship refers to the surface area of an expanding (Beryllium)sphere(tm). Most absorption loss is given by a 1/r relationship.
I sometimes have to go out to sea on scientific research cruises (like being in jail with the extra threat of drowning). I still make use a of compass as well as other simple devices, like a straightedge (ruler), protractor, or a piece of string. Precise navigation is performed using GPS, but the reliance on GPS (and canned software) sometimes leads to a lack of basic knowledge.
I once sailed with a watch stander that didn't know what a knot was (1 nautical mile per hour, approximately 0.5 m/s), nor did she know that a nautical mile equaled one minute of latitude.
I would love the opportunity to play with a sextant. When you out there at night, the stars are absolutely beautiful. After a while, you can sort of "compute" your course/heading by just looking at the stars.
It is strange that circles and ellipses were mentioned. Both of these functions are easily "visualized" using a piece of string and a couple of pushpins. Drawing a circle is easy; fixed length of string (radius) attached to a pin. Rotate string around the pin.
For an ellipse. attach the ends of the string to two pins (foci). Put pen inside string, pull taut, and rotate about the foci while keeping the string taut.
There are "tricks" like this that use string, pins, compasses, and rulers for other geometrical shapes.
I wonder if kids today get taught simple mathematical tricks. For instance, one can simply determine if a number is divisible by 3 by adding up the individual digits. If the sum is divisible by 3, then voila. For instance, 1872654. 1+8+7+2+6+5+4/3. Or more simply, 1+8, yes, 7+2 yes, 6 yes, 5+4 yes, so yes.
Want another one? What is 25*25? (2+1)*2=6. So the answer is 625. 55*55? (5+1)*5=30. So the answer is 3025.
I believe that your Grandfather worked on Hi-Frequency, Direction Finding (Huff-Duff) during WWI. Huff-Duff worked by obtaining the bearing (azimuth) of the receiver to the transmitter of a radio signal. The bearing was the one in which the radio signal had the largest amplitude. Obtain a second measurement at another location, and the position of the transmitter would be the intersection of the two bearings. A third (or more) measurement provides statistical improvement.
The importance of Huff-Duff in the Battle of the Atlantic is being more greatly appreciated because of the relatively recent declassification of military secrets from WWII. Enigma and radar tend to get all the credit, but Huff-Duff may have played a more important tactical role, especially during the earlier periods of the war.
Slashdot Mirror
A lot of dotcoms have gone paperless. No checks, no cash.
Remember Max Butler, aka Max Vision the guy the ran the whitehats website? He created a variant of a worm that attacked BIND, and had it patch the server. Unfortunately, he also introduced a backdoor.
/etc/inetd.conf file; enter this port and gain /bin/sh with root priveleges. Word gets out (or a bunch of script kiddies are using the same exploit), and soon everybody notices strange packets trying to access some weird port.
Last I heard he is still in jail (I maybe wrong about this).
And yes, for a while it was common for a cracker to close the security hole while leaving a "secret" backdoor. Sometimes this was accomplished by placing a bogus entry in one's
In the Windows world there are a bunch of trojans ports (27374, 31337, etc...). Unfortunately the back door was open to everybody.
Don't worry? It doesn't affect everyday life? Are you crazy?
When Jerry Bruckheimer realizes that the Earth's magnetic field flips back and forth, he going to make a movie about this. You know, impending doom for all mankind, blah, blah, blah. The only way to stop this is to detonate a nuclear device. But it has to be at the core-mantle boundary! That's like 2900 km down! He'll try to get Bruce Willis to drill the hole, but Bruce's character is dead! So what will we get? Yup, Ben Affleck in the leading role! And he's got to drill 2900 km not some easy 800 ft. Do you realize how long the movie is going to be? With Affleck on the screen the entire time?
Then your wife or gf is going to say that you both have to see this latest movie with *sigh* Ben Affleck.
But if you know geophysics, you could tell her why the premise is total b.s. It may be the only way out of this bad situation.
Learn Geophysics! Avoid Ben Affleck!
Actually, the understanding that the Earth's magnetic field periodically switches polarity was known before the discovery of the magnetic stripes on the seafloor. Bruhnes, in 1906, put forth the hypothesis that there were reversals.
The precise dating of these reversal became practical in the late 1950's due to great advances in K-Ar dating techniques. There was then a big effort to map out this sequence in the 1960'. Coincidentally, the first series of "detailed" magnetic maps of the seafloor were also becoming available in the 60's. In 1963, Vine and Matthew published the seminal paper that hypothesized that the magnetic stripes on the seafloor were related to seafloor spreading and the magnetic field reversals.
In 1965 Vine and Wilson used the best known magnetic time scale to match the pattern of seafloor stripes on the Juan de Fuca Ridge (off Washington state). In doing so, they were the first to compute a spreading rate. Unfortunately, the best available time scale was missing a key reversal, and hence their match was incorrect. They discretely "fixed" this problem a couple of years later using a better magnetic time scale.
Go to
this address in DC (2650 Wisconsin Ave NW). Knock on the door. Point to the roof and asked the occupants what is a "high gain omni" antenna.
How insane is it that Red Hat decided to ship the OS with telnet access off by default?
How sane is it to have a service that transmits plain text passwords turned on by default?
In SAIC's parlance, "Cyberpunkia" is the Metro stop on the blue line between Pentagon City and Arlington National Cemetary.
Another bit of trivia for those of you that visit DC. Prostitutes are easy to identify. They look just like well dressed business women except that they are wearing sneakers. Furthermore, there is free parking for Ryder rental vans on the 900 block of Pennsylvania Avenue, NW.
This is just a guess. Ultrasonic frequencies are greater than that that a human can hear. Higher frequencies also mean shorter wavelengths. This means that the sound source (e.g., transducer) can be equivalently smaller. One can then make a planar array of transducers that can be used to directional focus a beam of acoustic energy in a preferential azimuth. For instance, an Aegis cruiser's main radar array is a planar array.
But how does one then "hear" the signal in this directional acoustic signal. As others have pointed out there is something called the beating frequency when two signals interact. I would therefore have to surmise that the array contains two sets of arrays to transmit two different signals/ultrasonic frequencies. This might explain why he has problems at lower frequencies. The signals need to be closer in their frequency signal, which will also cause problems in the directional beam-forming.
Wish I could think about this a bit more, but I have to print a bunch of stuff right now.
Seminal. Seminal. Seminal. As in the original seed the begot, another, that begot another.
BTW, I only own two C books; note own. K&R 1st and 2nd Editions. Needed the latter one to get up to speed on the ANSI stuff. K&R is terse and does not have a lot of hand-holding examples. However, it did convert this FORTRAN progammer, non-CS major over to C in quick, efficient manner.
I must admit that K&R may not be very "practical" for someone without any programming experience. However, it is seminal.
Well for a seminal book on C there is by definition K&R First Edition. For C++ there is Stroustrup, First Edition. For Perl...
I have to agree that a bit (a lot?) of what Spafford wrote was a bit over the top. My favorite could have been written by somebody on /.
"The next generation of Navy aircraft carriers is going to have all weapons systems, propulsion, and command and control run by the very same system that you use at home to browse the Internet and play computer games. This is the same one that keeps coming up with "blue screens of death," which take on new, grim meaning in a military environment."
If Spafford had been a bit more toned down, he could have still made the same points without introducing vulnerabilies in his arguments that would make one cringe. OTOH, his points should be contemplated and analyzed. Computer/network security is pathetic if one considers the worse case scenario. A design error that is inherent in a commonly used protocol used by network routers could potentiall create havoc. Hmmm, didn't we come close to this one?
The role that DARPA played in the "early" days of computing is often overlooked. DARPA funded the initial prototype development of something called the Stanford University Network workstation. IIRC, a guy by the name of Joy at UCB also received DARPA funding to enhance some of the capabilites of a "new" OS called UNIX. Eventually, the two efforts joined forces and produced a commercial product.
RISC technology was pushed forward by DARPA. One effort eventually led to MIPS. Another effort led to the development of the RISC I and RISC II. This technology was licenced to Sun Microsystems, and eventually evolved into a more scalable architecture. I believe that this had some modest commercial success.
Warp and the Connection Machine were the result of DARPA funded efforts to push forward and test the capabilites of massively parallel computers. These were technnological wonders, but did not achieve commercial success. At least, one of these was featured in a very successful motion picture. Furthermore, thanks to MIPS, probably the geekiest line in motion picture history was spoken, "This is a UNIX system. I know this."
I would also have to speculate that a there are numerous computer industry leaders that had RA's in grad school via DARPA funding.
I good indication of how far AI has advanced is the fact that GRACE is a brunette and not a blonde. In the next major advance, GRACE will don glasses and be renamed VELMA.
Actually, that oil drum looks more like an industrial strength vacuum cleaner (wet-vacs). You know, the kind that could..., ummm, I better stop here.
In unrelated news, the Big Five auditing firm Arthur Andersen today announced that they have decided to increase the number of job placement interviews at Princeton University in the upcoming year. A spokeperson for Arthur Andersen said that the academic and social environment at Princeton helps to produce the type of high quality people that they desired for their firm.
Rental car companies in the United Arab Emirates don't need this black box. Foreign visitors just need to read this little blurb from the US State Dept web site.
Country-wide traffic laws impose stringent penalties for certain violations, particularly driving under the influence of alcohol. Penalties may include hefty jail sentences and fines, and, for Muslims, lashings. Persons involved in an accident in which another party is injured automatically go to jail until the injured person is released from the hospital. Should a person die in a traffic accident, the driver of the other car is liable for payment of compensation for the death (known as "dhiyya"), usually the equivalent of 41,000 U.S. dollars. Even relatively minor accidents may result in lengthy proceedings, during which both drivers may be prohibited from leaving the country.
I believe this policy also pertains to a foreign passenger in a taxi. I was told that part of the logic behind this is that the accident would not have taken place if the foreigner was not in the country. Obviously I didn't rent a car while I was there, and I closed my eyes and prayed (to Allah, Jesus, RMS, Buddha, the Big Kahuna, Chucky Cheese, etc...) when I was in a taxi.
12 cm must refer to the floppy disk version, while 12 inches is the hard disk.:-) Quite impressive. If they were marketing this product towards women they could nickname it Magic Johnson. Unfortunately, I believe that John Wayne Bobbitt already has dibs on this nick.
In related news, Pentagon officials at a hastily called press conference announced a successful test of the National Missile Defense system. The scheduling of this test was not publicized in advance due to concerns about terrorism. An anonymous DoD source stated that, "Ahhh, that was our test. We finally got it to work. No wait, in fact we have had many successful secret tests. Yeah, that's the ticket!"
My dog has fleas.
My dog has fleas.
My dog has fleas.
I've played the ukelele since I was a little kid. I own a Kamaka ukele whose value has appreciated with time; check out these prices.
http://www.ukes.com/kamaka.html
The only study that I will believe is one that make a positive correlation between playing video games and a decrease in one's ability to spell correctly.
This study would then be followed by one involving video games and grammar.
Absorption? Don't you mean geometrical spreading loss? The inverse-square relationship refers to the surface area of an expanding (Beryllium)sphere(tm). Most absorption loss is given by a 1/r relationship.
But your central point is well-taken.
I sometimes have to go out to sea on scientific research cruises (like being in jail with the extra threat of drowning). I still make use a of compass as well as other simple devices, like a straightedge (ruler), protractor, or a piece of string. Precise navigation is performed using GPS, but the reliance on GPS (and canned software) sometimes leads to a lack of basic knowledge.
I once sailed with a watch stander that didn't know what a knot was (1 nautical mile per hour, approximately 0.5 m/s), nor did she know that a nautical mile equaled one minute of latitude.
I would love the opportunity to play with a sextant. When you out there at night, the stars are absolutely beautiful. After a while, you can sort of "compute" your course/heading by just looking at the stars.
It is strange that circles and ellipses were mentioned. Both of these functions are easily "visualized" using a piece of string and a couple of pushpins. Drawing a circle is easy; fixed length of string (radius) attached to a pin. Rotate string around the pin.
For an ellipse. attach the ends of the string to two pins (foci). Put pen inside string, pull taut, and rotate about the foci while keeping the string taut.
There are "tricks" like this that use string, pins, compasses, and rulers for other geometrical shapes.
I wonder if kids today get taught simple mathematical tricks. For instance, one can simply determine if a number is divisible by 3 by adding up the individual digits. If the sum is divisible by 3, then voila. For instance, 1872654. 1+8+7+2+6+5+4/3. Or more simply, 1+8, yes, 7+2 yes, 6 yes, 5+4 yes, so yes.
Want another one? What is 25*25? (2+1)*2=6. So the answer is 625. 55*55? (5+1)*5=30. So the answer is 3025.
I believe that your Grandfather worked on Hi-Frequency, Direction Finding (Huff-Duff) during WWI. Huff-Duff worked by obtaining the bearing (azimuth) of the receiver to the transmitter of a radio signal. The bearing was the one in which the radio signal had the largest amplitude. Obtain a second measurement at another location, and the position of the transmitter would be the intersection of the two bearings. A third (or more) measurement provides statistical improvement.
The importance of Huff-Duff in the Battle of the Atlantic is being more greatly appreciated because of the relatively recent declassification of military secrets from WWII. Enigma and radar tend to get all the credit, but Huff-Duff may have played a more important tactical role, especially during the earlier periods of the war.
Spring time for Linux and Germany.
Winter for Ballmer and Gates.