Very interesting. The goal of a space elevator tether is longitudinal strength, which means that the links would be stretched along one axis. I wonder if the folds and pinches at the top and bottom would cause any problems, and if you'd have to make a chain link out of a large number of nanotubes to prevent pinching. And what about rubbing?
You mention cutting an individual fiber and thereby causing the whole fabric to unravel. For a space elevator, the prevaling thinking is to make a composite material (say, fibers and epoxy) with a matrix strong enough to redistribute load among nearby fibers in case of a localize break within the tether.
Unfortunately, the cable is too long to send power through efficiently, since it has to reach up at least to geosynchronous orbit. Estimates of conductivity for a composite fiber are in the range of copper or other good metallic conductors. You'd get a heck of a lot of resistance through 25,000 miles of cable. Gotta beam it down or something.
According to this calculator, 25,000 miles of copper with 1 cm^2 cross section (probably an over-estimate), would have a resistance of about 6700 Ohm.
...There are compilers which can do optimizations on profiling data from the actual running program. Beat that java....
I don't want to be partisan here, but that's exactly what Sun's Hotspot JVM does (note: article from 1998 -- first hit on Google hotspot optimizations).
The Sun JVM analyzes run-time profiling data in real time as the code executes and optimizes the "hot spots". In practice, you can even see it -- if you run a loop many times, the first few times after the JVM starts it will usually run slowly, and then it will speed up as the hot spot compiling kicks in.
Note: for 10x the storage, you have to buy the 40GB model, which is $500, rather than $300, which makes it 2x expensive for 10x the storage, rather than $50 more for 10x the storage.
Still, a pretty dramatic upgrade from 4 to 15, if you need those 11 additional GBs.
I dunno -- somehow, I think Google's page ranker is more likely to attain sentience than any humanoid robot.
I mean, what's the electronic equivalent of primordial soup where the nucleic acids of synthetic reasoning can start coming together to form unsuspected new orders? I doubt it's within the small metal skull of a trigonometry-dominated walking robot -- I think that it is much more likely submerged beneath the seething oceans of information, on some relatively stable rock where correlations can start to grow.
Those two obstacles are mentioned in the Wired article, with an answer to the first one (monocrystalline CVD-grown diamond) and a hint of the second one (p-type dopant).
I kind of liked it. I could guess each question pretty easily from its answer. It might not work well with all interviews, but with this one I think it helped the flow overall. It made it read like one long discourse, which it was, more than other interviews.
Of course, I don't hear the bad reviews or see them. All I know is the glowing notices that people read to me that some reviewer thinks I'm wonderful. So I've slowly come to think that I'm wonderful.
I think John Belushi probably did the best.
I think the whole interracial kiss thing has been overrated. Nichelle Nichols was a beautiful woman and her lips were full. I merely sought to make an impression.
Ok, I'll be honest. It was a laugh. Pure & simple. You should have at least been mildly amused. It seems to me that you need to get a life.
Actually, I don't think that actors think much about MPAA. They're more concerned about AARP.
Yes, I enjoyed it. I think Tim Allen was very funny. As for accuracy, not at all.
Oh Contrare. That's French, in case you need it, for 'to the contrary.' I had a great time at McGill. I did go to a ceremony at the student union building and my feeling about McGill is that it's a great university and it produced many great students. Unfortunately, I was not one of them.
Thank you for asking about Nerine's fund. It benefits a rehabilitation place called Friendly House. They do wonderful work. Nerine has a rehabilitation home with her name on it and my hope and sympathy is for these recovering women.
Dear Will,
We are so cool, we're beyond cool. We are in orbit man. I don't do pre-game strategy.
I look forward to some personal time with you.
Regret is the worst of human emotions. There is no going back with regret. There is no future with regret. Regret is not something I live with. If there is something I wished I hadn't done, I don't do it anymore or I forgive myself and try better.
My life is my statement and I try to be true to myself and thusly to other people. Whatever my failings are, they are human and I try to perfect it each day.
Actually, you know what? I think I like that one better the new way too!
The article isn't clear (okay, the Microsoft guy in the article isn't clear), but it doesn't seem like the Microsoft non-compete agreement is being invoked -- it's more like Software Image got nervous about the SCO suit and said that it's the Linux users' responsibility to show that they own or license the relevant intellectual property.
So how would one prove to a skeptic that one has a right to use the intellectual property contained in a Knoppix distro? That's a lot of code, and I doubt its covered by just one license!
They must have some sort of lighting in mind. According to this graph, power required for a legible display increases as the ambient light goes away. The simple explanation is "someone is turning on a light". But their site doesn't give any details. Side-lighting, maybe?
More likely, higher pixel density is a necessary aspect of their technology. The individual MMS mechanisms are so tiny they probably can't handle very large pixels. Now, controlling all those pixels independently will take a lot of bandwidth.
If it's emitting light (LEP), I'll betcha it's consuming some energy:).
Iridigm's displays, on the other hand, are reflective -- that is, not emitting (or generating) their own light. That's why they can claim zero power for a static display.
pretty cool for a framed picture of grandkids that gets updated once a week, I'd say!
On top of that, I think you should add about 30% for 64-bit processing. I don't know what the numbers would really be, especially since they are so dependent on recompiling to take advantage of 64 bits. But assuming the OS at least is recompiled, I'd venture there would be a significant speedup from moving those extra bits through the CPU faster. Total: 1.3 x 1.3 = 1.69. 69% speedup? I really have no idea without benchmarks, though:)
The 970 is capable of a maximum of 8 instructions per cycle, simply because it has eight execution units. In practice, this depends very heavily on the code it is executing (compiler, inherent parellelism, hand-optimised assembly, etc.). The P4 also has several parallel execution units (5?), including a single ALU that is double-pumped and acts kinda like two ALUs, since it can handle two instructions per cycle.
But the really big difference is number of registers. In short, the more registers you have, the more instructions you'll be able to run in parallel, in general. The PowerPC architecture, like many RISC architectures, specifies 32 general-purpose registers, whereas the P4 specifies only 8. With 32, there's a lot more room for recognizing parallelism by singling out which operations depend on the result of which other operations. Such dependencies force you to run operations sequentially, whereas the lack of such dependencies allows you to run them in parallel.
The chip with more registers, therefore, will take better advantage of its parallel execution units. It's also a good reason for Intel to pump up the clock speed (although doing it at the expense of pipeline depth can be counterproductive) while IBM pumps up the parallelism.
Seriously, there is one XP feature that really itches my back right where I like it: multiple-users-logged-in-simultaneously. Does OS X also offer anything like it? Instead of logging my wife off our PC, I switch users (one keystroke: windows-L), click on my own login icon, type my password, and wait about five seconds for my desktop to come up, complete with an unclosed session -- usually something like emacs, PuTTY, WinCVS, Outlook, IE:p
I know, of course that OS X allows multiple users, and its support for multimedia is much better, but does it allow them simultaneously?
For answers to all these problems, see this paper. In short:
Yes, a crack across the ribbon would be bad. But you can make the ribbon be several loosely-coupled parallel sub-ribbons that give a little but don't separate completely when one of them breaks. And yes, you'd have to repair it pretty quickly. At altitudes with lots of space debris, you can make it extra-wide and extra-strong for redundancy, and add only a fraction of a percent to the mass of the overall cable.
Lightning strikes can be avoided by going to the right place on the surface of the earth. Parts of the equatorial Pacific receive lightning strikes less than once every few years. And a mobile base station could move the bottom of the cable out of the way of small storms. There are also possible lightning rod approaches for typical storm altitudes (weather balloons, for instance).
Shorting out the ionosphere -- given the sheer length of the tether, even if it were as conductive as gold, the resistance between the ionosphere and ground of tens to hundreds of thousands of ohms.
So yes, there are many challenges to overcome, but they all, fortunately, seem surmountable.
Slashdot Mirror
Smaller galaxy cluster. But I don't know. Maybe the clusters got tangled up somehow? I haven't yet RTFA.
You mention cutting an individual fiber and thereby causing the whole fabric to unravel. For a space elevator, the prevaling thinking is to make a composite material (say, fibers and epoxy) with a matrix strong enough to redistribute load among nearby fibers in case of a localize break within the tether.
According to this calculator, 25,000 miles of copper with 1 cm^2 cross section (probably an over-estimate), would have a resistance of about 6700 Ohm.
I don't want to be partisan here, but that's exactly what Sun's Hotspot JVM does (note: article from 1998 -- first hit on Google hotspot optimizations).
The Sun JVM analyzes run-time profiling data in real time as the code executes and optimizes the "hot spots". In practice, you can even see it -- if you run a loop many times, the first few times after the JVM starts it will usually run slowly, and then it will speed up as the hot spot compiling kicks in.
I thought dialup tended to be 37 to 53 kbps -- that would make the low end of this technology comparable to dialup ...
Now, that didn't happen in this case, as the story was already on the front page before Slashdot linked it. But it could happen, no?
At least had the decency to post as AC though ...
Still, a pretty dramatic upgrade from 4 to 15, if you need those 11 additional GBs.
I believe the word license in this sense is:
(from Webster's)Implying that non-good men love the opportunity to act irresponsibly, which is what freedom offers them.
I dunno -- somehow, I think Google's page ranker is more likely to attain sentience than any humanoid robot.
I mean, what's the electronic equivalent of primordial soup where the nucleic acids of synthetic reasoning can start coming together to form unsuspected new orders? I doubt it's within the small metal skull of a trigonometry-dominated walking robot -- I think that it is much more likely submerged beneath the seething oceans of information, on some relatively stable rock where correlations can start to grow.
Perhaps you are confusing it with Quotations from Chairman Mao?
Those two obstacles are mentioned in the Wired article, with an answer to the first one (monocrystalline CVD-grown diamond) and a hint of the second one (p-type dopant).
I kind of liked it. I could guess each question pretty easily from its answer. It might not work well with all interviews, but with this one I think it helped the flow overall. It made it read like one long discourse, which it was, more than other interviews.
The effect would have been entirely different with William Shatner's infamous interview ...
Actually, you know what? I think I like that one better the new way too!
So how would one prove to a skeptic that one has a right to use the intellectual property contained in a Knoppix distro? That's a lot of code, and I doubt its covered by just one license!
- Lower power, due to being reflective (passive) rather than light-emitting.
- Visible even in direct sunlight, for the same reason.
- Blue elements don't wear out after a few hundred hours (the biggest problem with OLEDs).
Being reflective is also a disadvantage -- you need a light to see it in the dark. But not a very big one, probably.They must have some sort of lighting in mind. According to this graph, power required for a legible display increases as the ambient light goes away. The simple explanation is "someone is turning on a light". But their site doesn't give any details. Side-lighting, maybe?
More likely, higher pixel density is a necessary aspect of their technology. The individual MMS mechanisms are so tiny they probably can't handle very large pixels. Now, controlling all those pixels independently will take a lot of bandwidth.
Iridigm's displays, on the other hand, are reflective -- that is, not emitting (or generating) their own light. That's why they can claim zero power for a static display.
pretty cool for a framed picture of grandkids that gets updated once a week, I'd say!
I assume those numbers are for one Power4 core, but I didn't see confirmation in the article. Do you know?
On top of that, I think you should add about 30% for 64-bit processing. I don't know what the numbers would really be, especially since they are so dependent on recompiling to take advantage of 64 bits. But assuming the OS at least is recompiled, I'd venture there would be a significant speedup from moving those extra bits through the CPU faster. Total: 1.3 x 1.3 = 1.69. 69% speedup? I really have no idea without benchmarks, though :)
But the really big difference is number of registers. In short, the more registers you have, the more instructions you'll be able to run in parallel, in general. The PowerPC architecture, like many RISC architectures, specifies 32 general-purpose registers, whereas the P4 specifies only 8. With 32, there's a lot more room for recognizing parallelism by singling out which operations depend on the result of which other operations. Such dependencies force you to run operations sequentially, whereas the lack of such dependencies allows you to run them in parallel.
The chip with more registers, therefore, will take better advantage of its parallel execution units. It's also a good reason for Intel to pump up the clock speed (although doing it at the expense of pipeline depth can be counterproductive) while IBM pumps up the parallelism.
I know, of course that OS X allows multiple users, and its support for multimedia is much better, but does it allow them simultaneously?
Just make sure you have a good driver up there!
So yes, there are many challenges to overcome, but they all, fortunately, seem surmountable.