About a decade ago I went with cash in hand to several data recovery companies and asked them to recover some wiped files on a working disk. Distructive techniques were allowed, and the budget would have paid for some elaborate processes. Several first-level telephone answering folks said "sure, we can do it", but when I told the same story to the next level no one was willing to try.
There is, of course, that old report claiming that there is enough information physically present in a multiply erased bit position to permit recovery. Maybe the intelligence agencies can do it, but I have heard of no verified case where they - or anyone else - actually did.
Well, strictly speaking, the energy is coming from the gravitational interaction between the infalling matter and the black hole. The arrangement of the hole and disk when a piece of disk is closer to the hole is more negative than when it is farther (the gravitational attraction does work on the material as it falls) and some of the energy given up there ends up powering the motion of the disk, which in turn twists the magnetic fields. The mass-energy of the black hole itself is not depleted here, where in contrast Hawking radiation does reduce the mass-energy of the hole. When it has eaten all of its disk, the hole will end up more massive than it was, but less massive than the original hole-plus-disk system. The eating process sends some energy away in this along with other ways.
This is radiation from the accretion disk, which both supplies the material and twists up the fields which then accelerate the material. It's not from the hole itself. Of course it is all powered by the hole's gravitational field.
This is a good article. It was complete enough to satisfy the casual interest of this old physicist who once worked for awhile as an astronomer, explained all of its terms in ways accessible to a more general public, but was never tedious about it. We need more science writing of that quality.
Also good work, it would seem. Rarely do you get a chance to check astrophysical theory in such detail against observations.
Their ancestor is already a commercial success.
The processor used to demonstrate this technology is the MSP430 line of low-power microcontrollers from TI. It is 16-bit Von Neumann RISC with an address space stretched to 1mB that with present technology runs at 3V using about 500uA/mHz. It will run up to 14MHz at 3V and does register-to-register operations in one clock tick, to and/or from memory in 2 to 6 depending. It idles at 0.1uA waiting for an interrupt, or at 0.6uA when keeping time with a 32KHz on-chip crystal oscillator. The family includes models with hardware multiplier, lots of handy embedded peripherals including 12-bit ADC, DAC, timers, serial ports of various types and so on.
They will never power a general purpose computer, but they are a serious competitor in the market now served by PIC. I use them routinely in extremely low-power embedded applications and like the family a lot.
In an essay published some time ago, Si Fi author Ursula LeGuin came down hard against the idea that one should even expect her art to be a prediction of the future. She went down a list that included prophets, touts, and futurists, and didn't find herself anywhere among them. So she gave up decades ago.
Eudora's home page http://www.eudora.com/ says that the paid mode Eudora is no longer available, and that an open source version of Eudora is being developed by Mozilla. An article at http://www.mozillazine.org/talkback.html?article=2 0078 says that the new Eudora will be based on the Thunderbird engine. This is apparently the Penelope project http://wiki.mozilla.org/Penelope , which claims not to be trying to supplant Thunderbird, but may be about to do so. Would an insider please clarify all this?
An example: A few days ago I had to explain to a very competent desktop programmer, who was doing the unfamiliar job of writing test C code to be ported to an MSP430 embedded processor, that taking an integer modulo 1440 was a bad idea. The MSP430 has no divide instruction, so the modulo had to compile to a division subroutine made of subtractions, tests, and shifts. In this case there was a way to code the overall task that evaded the need for the modulo.
When doing embedded C on a processor of that size (still a lot bigger than a PIC) I ALWAYS look at the compiler output when I am writing anything where I care about either size or speed of execution.
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About a decade ago I went with cash in hand to several data recovery companies and asked them to recover some wiped files on a working disk. Distructive techniques were allowed, and the budget would have paid for some elaborate processes. Several first-level telephone answering folks said "sure, we can do it", but when I told the same story to the next level no one was willing to try. There is, of course, that old report claiming that there is enough information physically present in a multiply erased bit position to permit recovery. Maybe the intelligence agencies can do it, but I have heard of no verified case where they - or anyone else - actually did.
Well, strictly speaking, the energy is coming from the gravitational interaction between the infalling matter and the black hole. The arrangement of the hole and disk when a piece of disk is closer to the hole is more negative than when it is farther (the gravitational attraction does work on the material as it falls) and some of the energy given up there ends up powering the motion of the disk, which in turn twists the magnetic fields. The mass-energy of the black hole itself is not depleted here, where in contrast Hawking radiation does reduce the mass-energy of the hole. When it has eaten all of its disk, the hole will end up more massive than it was, but less massive than the original hole-plus-disk system. The eating process sends some energy away in this along with other ways.
This is radiation from the accretion disk, which both supplies the material and twists up the fields which then accelerate the material. It's not from the hole itself. Of course it is all powered by the hole's gravitational field.
This is a good article. It was complete enough to satisfy the casual interest of this old physicist who once worked for awhile as an astronomer, explained all of its terms in ways accessible to a more general public, but was never tedious about it. We need more science writing of that quality. Also good work, it would seem. Rarely do you get a chance to check astrophysical theory in such detail against observations.
Their ancestor is already a commercial success. The processor used to demonstrate this technology is the MSP430 line of low-power microcontrollers from TI. It is 16-bit Von Neumann RISC with an address space stretched to 1mB that with present technology runs at 3V using about 500uA/mHz. It will run up to 14MHz at 3V and does register-to-register operations in one clock tick, to and/or from memory in 2 to 6 depending. It idles at 0.1uA waiting for an interrupt, or at 0.6uA when keeping time with a 32KHz on-chip crystal oscillator. The family includes models with hardware multiplier, lots of handy embedded peripherals including 12-bit ADC, DAC, timers, serial ports of various types and so on. They will never power a general purpose computer, but they are a serious competitor in the market now served by PIC. I use them routinely in extremely low-power embedded applications and like the family a lot.
This showed up some time ago and was then an obvious put-on. Wish I had the original reference.
In an essay published some time ago, Si Fi author Ursula LeGuin came down hard against the idea that one should even expect her art to be a prediction of the future. She went down a list that included prophets, touts, and futurists, and didn't find herself anywhere among them. So she gave up decades ago.
Eudora's home page http://www.eudora.com/ says that the paid mode Eudora is no longer available, and that an open source version of Eudora is being developed by Mozilla. An article at http://www.mozillazine.org/talkback.html?article=2 0078 says that the new Eudora will be based on the Thunderbird engine. This is apparently the Penelope project http://wiki.mozilla.org/Penelope , which claims not to be trying to supplant Thunderbird, but may be about to do so. Would an insider please clarify all this?
An example: A few days ago I had to explain to a very competent desktop programmer, who was doing the unfamiliar job of writing test C code to be ported to an MSP430 embedded processor, that taking an integer modulo 1440 was a bad idea. The MSP430 has no divide instruction, so the modulo had to compile to a division subroutine made of subtractions, tests, and shifts. In this case there was a way to code the overall task that evaded the need for the modulo. When doing embedded C on a processor of that size (still a lot bigger than a PIC) I ALWAYS look at the compiler output when I am writing anything where I care about either size or speed of execution.