Level 5 RAID has both high performance and high reliability (striping with distributed parity), at the expense of less capacity. I don't think you can do it in software, though, so you need a hardware RAID controller (prob. not a big expense). One thing I like about the Apple controller is that it's dual redundant.
I'm not working directly with NASA (don't ask. NO - don't.), but I don't believe anyone's flown a RAID before. Alternatives ARE being considered, but I speculate that/. folks have more RAID experience than all of NASA put together. They have hardrives on the laptops they have used in the past to support Getaway Specials and other experiments, but these are not up to speed for the application.
I doubt the little bit of momentum in a few hard drives could be a factor, but fortunatelt angular momentum is a vector quantity, so it would always be possible to orient half of them "upside down" so the net momentum is zero.
Heat and Perfformance
on
RAID for Zero-G?
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· Score: 3, Interesting
The heat is a concern, and the lower the power dissipation, the better.
The RAID performance in orbit doesn't need to be top drawer, but when it returns to Earth, I want it to perform well and not be a hassle to administer or set up, since there's a lot of data to analyze.
Re:I don't have an answer, but...
on
RAID for Zero-G?
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· Score: 4, Informative
Shuttle middeck. It's an environment beningn enough for humans, so not as bad as an ELV ride. The drives would be off and parked during ascent.
What about the real stuff? Jazz that only rehashes the past isn't jazz, IMO. Innovation is its life blood.
There are some great living players. Here are a few:
Henry Threadgill - alto player and a great composer who easily gets bored of reepeating himself.
Susie Ibarra - drummer/composer with Eastern influences. A thoughtful, subtle player.
Myra Melford - pianist and composer who often works with some of the best players around. Her album Above Blue is terrific.
Dave Douglas - the Masada trumpet player.
Ken Vandermark - terrific sax player and sophsiticated composer
Ornette Coleman is still alive and kicking, and will continue to challenge.
Egberto Gismonti - if you want something a little softer but still brilliantly conceived and executed.
And of course, John Zorn, who resists labeling as agressively as anyone, but is one of the most talented and accomplished (and devious) musicians we have anywhere in the world
Of those no longer living, I don't see any mention of Eric Dolphy, who was one of the greatest improvisational geniuses of whom we have an accurate record. Check out Out to Lunch to get your neurons humming.
Zorn's Masada recordings aren't what I would call easy listening, but they are melodic and accessible, and you don't have to like Klezmer to get into them. Very high energy stuff, and usually featuring one of the world's greatest drummers, Joey Baron.
You may be interested in this fine lecture by Judea Pearl that discusses the relationship between correlation and causation. It IS possible to speak meaningfully about causality.
Yes, programmers have erred. To err is human, to allow errors to propagate into mission failures is a failure of systems engineering, and I think that is where the real blame lies. A lot of the problem is thatspacecraft systems engineers often have a very amateurish grasp of software, if any at all.
For example, on Mars Climate orbiter, a junior programmer failed to properly understand the requirements. However, systems failed to:
Properly identify the thruster force data as a critical interface.
Failed to demand proper, thorough and timely verification ON BOTH SIDES OF THE INTERFACE.
Failed to make sure the requirements were properly understood by the implementers.
Ignored or missed prima-facie evidence that the interface wasn't working (closely related to 1).
This has been batted around for several years now. It's an interesting controversy, since the scientific community studying Mars life has seen a lot of turnover since then. We're going to have to wait for the new data.
There are flaws in their scheme that Apple will have to address. For one, a 0:14 second Naked City track costs the same as a 16 minute Ravi Shankar track. I'm not inclined to pay a dollar to donwload a 0:14 track, even though it's packed with goodness. On the other hand, I feel like I'm shortchanging poor maestro Shankar. Also, the selection's not so great so far.
UFOs, as flown by some extra-terrestial intelligent beings, might generally be rather small objects. Space is big. SOHO's cameras do not have extremely good resolution and any visible object would have to be either enormous, very bright, or somewhat close to SOHO (and Earth), but between SOHO and Sun. Somehow that wouldn't seem to make much sense.
The LASCO coronograph is actually three telescopes. The tightest field of view looks out to 3 Solar radii. Even this is about a 0.03 radian field of view, so that something spacecraft-ish in size (even very large) would have to be quite close to make a good image. I get that a kilometer size image could be no further than about 10^5 km to even be a one pixel image. To register on several pixels in the tightest telescope, we're talking about 10^4 kilometers max for a big object. That's pretty close for deep space.
Proof is what mathematicians and logicians do, not scientists. Scientific evidence is of a statistical nature, and tends to support one hypothesis or a range of hypotheses more than others. The ultimate status of a hypothesis is not that it's proven, but that it becomes a FACT - consistent with a large body of well-verified data in that domain of inquiry, with meaningful explanatory power and no serious unexplained anomalies.
It is, for example,a fact that the Earth is a spheroidal body that rotates about its axis with a small amount of nutation, but there is a tiny bit of uncertainty as to where pole is at any given time, and exactly how aspherical the Earth is.
The theory here is that most spam still comes in via open relays, and
the only way we are going to convince them to clean up their act is to
waste _their_ disk space, their time, and their network bandwidth more
than they waste ours.
To me, this seems exactly the right strategy, although how well it works in practice will be interesting to watch.
They don't just use FTP. That's just one port for getting data to and from the spacecraft in batches (which is usually a perfectly acceptable way to get data in and out). See their whitepaper. They can also telnet to the 750, and hve other services as well.
Quarterly earnings are at best a snapshot and are hugely overemphasized. This latest is really just breaking even and change. Still, Redhat is not bleeding cash like many other companies in similar markets. I think their long term prospects are respectable.
They're trading at around $6.55 this morning. The prospects for a quick killing at that price are poor, but haven't we all learned our lesson?
This guy did the same thing with Star Wars. He can be pursuasive, and his essays are fun to read, but I urge people not to be sucked in. His opposition to the good/evil dichotomy and benevolent monarchy smack of moral relativism and a devotion to the global superstate. The end of his reasoning is the destruction of the individual in favor of the collective. He's threatened by the notion of heroes, because heroism is essentially individualistic. Just another cardboard intellectual selling out our liberty.
You must have read a different essay than I did, because his support for Enlightenment values is anything but an attack on individualism. Good monarchs are largely a fantasy, and notions of an agrarian utopia are entirely a fantasy.
But the space station really isn't good for anything except science, and it's not very good at that either.
It's time to knife this baby.
Possibly true, but in the spirit of throwing good money afer bad, we ought to see if we can come up with a real use for it - if nothing else, we could shoot movies there.
Well said. There are serious problems with the ISS in concept and in execution, but its biggest problem is how much it has cost and is likely to cost in the future. And NASA has NEVER had a good handle on what those costs will be. Congress has bigger fish to fry, but sooner or later they're going to get infuriated at all the flim-flam
I think the best thing to do is de-crew the ISS for a year or two, with 2-3 shuttle flights a year to check it out. Everyone else stand down, and no more damn presidential commissions - let's get serious about deciding what to do with this thing and what it's worth paying for.
That said, I don't think the justification needs to be purely scientific. The critics of manned space flight have always had the argument that for the short to medium term, better research can be done for the same money. It's a good argument, if the only return you're looking for is scientific.
A high proportion of the Amazon reviews are 5 stars. That's largely becuase they're posted by people who are enthusiasts for the item in question. I've even posted a few 5-star reviews myself, but I quickly get tired of gushing. Most of my reviews are in the 2-4 range. 4 means I think it's very good, with no uncorrectable flaws.
It's more fun to post a well-deserved 1-star and watch the adoring faithful get mad as hell.
Not strictly true. Most NASA spacecraft are built by contractors, but not all. GSFC has built several small satellites at their own facility with a mix of Civil Service and contractor labor. They also build science instruments to fly on satellites.
NASA does have a long standing problem of attracting technical talent to the NASA ranks in sufficient numbers. It is also far more difficult to lay off civil servants when budgets are cut. That is why they use so many contractors, and will likely always do so.
I hate to say it, but it may be time to suck it up admit the reality that continued funding of the ISS is good money after bad. Whole careers have been poured into it, and AT LEAST $40 billion current-year dollars (prob. much more), and there's little prospect we'll have much to show for it. And no, it ain't no waystation to Mars or the Moon. This would largely ground the shuttle, but that wold also save big bucks.
For the same billions, we could mount really aggressive Mars and Europa programs and learn how to build a lunar colony.
BTW, please see next time you want to post a long URL.
ISS is also useless as such a waypoint. When its orbit plane intersects the Ecliptic, the amount of plane change required is too high to be practical. However, fuel efficiency is not the worst problem - ISS simply isn't designed as a waypoint and there's presently no compelling argument for one in the manner you describe.
A waypoint only makes sense if the fuel is manufactured in situ, and there's no conceivable way to do that at ISS.
Re:Biggest problem with macroevolution...
on
Shapes of Time
·
· Score: 3, Interesting
Two problems with this contentin that I can see right off the bat:
The problem of the biosphere as a dynamical system hasn't even been adequately formulated, much less solved. It's simply too complex, even if we assume we have enough data about its pressnt state. There are very simple dynamical systems that exhibit very complex behavior and easilt "forget" their initial conditions. How can we then say what the initial conditions for the biosphere would necessarily be?
In The Blind Watchmaker, Dawkins argues persuasively that evolution should be counterintuitive. If you are saying "I just don't see how it could all happen," then this is not at all surprising.
Slashdot Mirror
Level 5 RAID has both high performance and high reliability (striping with distributed parity), at the expense of less capacity. I don't think you can do it in software, though, so you need a hardware RAID controller (prob. not a big expense). One thing I like about the Apple controller is that it's dual redundant.
I'm not working directly with NASA (don't ask. NO - don't.), but I don't believe anyone's flown a RAID before. Alternatives ARE being considered, but I speculate that /. folks have more RAID experience than all of NASA put together. They have hardrives on the laptops they have used in the past to support Getaway Specials and other experiments, but these are not up to speed for the application.
I doubt the little bit of momentum in a few hard drives could be a factor, but fortunatelt angular momentum is a vector quantity, so it would always be possible to orient half of them "upside down" so the net momentum is zero.
The heat is a concern, and the lower the power dissipation, the better.
The RAID performance in orbit doesn't need to be top drawer, but when it returns to Earth, I want it to perform well and not be a hassle to administer or set up, since there's a lot of data to analyze.
Shuttle middeck. It's an environment beningn enough for humans, so not as bad as an ELV ride. The drives would be off and parked during ascent.
What about the real stuff? Jazz that only rehashes the past isn't jazz, IMO. Innovation is its life blood.
There are some great living players. Here are a few:
Of those no longer living, I don't see any mention of Eric Dolphy, who was one of the greatest improvisational geniuses of whom we have an accurate record. Check out Out to Lunch to get your neurons humming.
Zorn's Masada recordings aren't what I would call easy listening, but they are melodic and accessible, and you don't have to like Klezmer to get into them. Very high energy stuff, and usually featuring one of the world's greatest drummers, Joey Baron.
Excellent post, and I largely agree.
You may be interested in this fine lecture by Judea Pearl that discusses the relationship between correlation and causation. It IS possible to speak meaningfully about causality.
Yes, programmers have erred. To err is human, to allow errors to propagate into mission failures is a failure of systems engineering, and I think that is where the real blame lies. A lot of the problem is thatspacecraft systems engineers often have a very amateurish grasp of software, if any at all.
For example, on Mars Climate orbiter, a junior programmer failed to properly understand the requirements. However, systems failed to:
This has been batted around for several years now. It's an interesting controversy, since the scientific community studying Mars life has seen a lot of turnover since then. We're going to have to wait for the new data.
There are flaws in their scheme that Apple will have to address. For one, a 0:14 second Naked City track costs the same as a 16 minute Ravi Shankar track. I'm not inclined to pay a dollar to donwload a 0:14 track, even though it's packed with goodness. On the other hand, I feel like I'm shortchanging poor maestro Shankar. Also, the selection's not so great so far.
Besides, I've already found 1 bug in iTunes 4.
some very good points:
The LASCO coronograph is actually three telescopes. The tightest field of view looks out to 3 Solar radii. Even this is about a 0.03 radian field of view, so that something spacecraft-ish in size (even very large) would have to be quite close to make a good image. I get that a kilometer size image could be no further than about 10^5 km to even be a one pixel image. To register on several pixels in the tightest telescope, we're talking about 10^4 kilometers max for a big object. That's pretty close for deep space.
There are lots of useful X apps that will never make the trip to Cocoa, but many of us would still like to run on OS X. See Fink for a long list.
Aqua is just the look and feel of OS X. Quartz is the graphics engine, which I believe the X11 port makes use of.
Proof is what mathematicians and logicians do, not scientists. Scientific evidence is of a statistical nature, and tends to support one hypothesis or a range of hypotheses more than others. The ultimate status of a hypothesis is not that it's proven, but that it becomes a FACT - consistent with a large body of well-verified data in that domain of inquiry, with meaningful explanatory power and no serious unexplained anomalies.
It is, for example,a fact that the Earth is a spheroidal body that rotates about its axis with a small amount of nutation, but there is a tiny bit of uncertainty as to where pole is at any given time, and exactly how aspherical the Earth is.
To me, this seems exactly the right strategy, although how well it works in practice will be interesting to watch.
They don't just use FTP. That's just one port for getting data to and from the spacecraft in batches (which is usually a perfectly acceptable way to get data in and out). See their whitepaper. They can also telnet to the 750, and hve other services as well.
Quarterly earnings are at best a snapshot and are hugely overemphasized. This latest is really just breaking even and change. Still, Redhat is not bleeding cash like many other companies in similar markets. I think their long term prospects are respectable.
They're trading at around $6.55 this morning. The prospects for a quick killing at that price are poor, but haven't we all learned our lesson?
You must have read a different essay than I did, because his support for Enlightenment values is anything but an attack on individualism. Good monarchs are largely a fantasy, and notions of an agrarian utopia are entirely a fantasy.
Possibly true, but in the spirit of throwing good money afer bad, we ought to see if we can come up with a real use for it - if nothing else, we could shoot movies there.
Well said. There are serious problems with the ISS in concept and in execution, but its biggest problem is how much it has cost and is likely to cost in the future. And NASA has NEVER had a good handle on what those costs will be. Congress has bigger fish to fry, but sooner or later they're going to get infuriated at all the flim-flam
I think the best thing to do is de-crew the ISS for a year or two, with 2-3 shuttle flights a year to check it out. Everyone else stand down, and no more damn presidential commissions - let's get serious about deciding what to do with this thing and what it's worth paying for.
That said, I don't think the justification needs to be purely scientific. The critics of manned space flight have always had the argument that for the short to medium term, better research can be done for the same money. It's a good argument, if the only return you're looking for is scientific.
A high proportion of the Amazon reviews are 5 stars. That's largely becuase they're posted by people who are enthusiasts for the item in question. I've even posted a few 5-star reviews myself, but I quickly get tired of gushing. Most of my reviews are in the 2-4 range. 4 means I think it's very good, with no uncorrectable flaws.
It's more fun to post a well-deserved 1-star and watch the adoring faithful get mad as hell.
Excuse me? A port to where? Even if ISS were in a better orbit, it isn't designed to be any sort of port, and here are NO PLANS to make it into one.
Not strictly true. Most NASA spacecraft are built by contractors, but not all. GSFC has built several small satellites at their own facility with a mix of Civil Service and contractor labor. They also build science instruments to fly on satellites.
NASA does have a long standing problem of attracting technical talent to the NASA ranks in sufficient numbers. It is also far more difficult to lay off civil servants when budgets are cut. That is why they use so many contractors, and will likely always do so.
I hate to say it, but it may be time to suck it up admit the reality that continued funding of the ISS is good money after bad. Whole careers have been poured into it, and AT LEAST $40 billion current-year dollars (prob. much more), and there's little prospect we'll have much to show for it. And no, it ain't no waystation to Mars or the Moon. This would largely ground the shuttle, but that wold also save big bucks.
For the same billions, we could mount really aggressive Mars and Europa programs and learn how to build a lunar colony.
BTW, please see next time you want to post a long URL.
ISS is also useless as such a waypoint. When its orbit plane intersects the Ecliptic, the amount of plane change required is too high to be practical. However, fuel efficiency is not the worst problem - ISS simply isn't designed as a waypoint and there's presently no compelling argument for one in the manner you describe.
A waypoint only makes sense if the fuel is manufactured in situ, and there's no conceivable way to do that at ISS.
Two problems with this contentin that I can see right off the bat: