Shouldn't Linux not break their ABI with every new kernel release?
Linux doesn't. The Applications Binary Interface is remarkably stable in Linux, all things considered. The kernel internal interface is of course fair game, since it's all source code anyway (a few vendors' proprietary drivers notwithstanding). I've got 2.4.x application binaries that work just fine on 2.6.x.
Predictable doesn't mean easy. Lunar temperatures have something like a +/- 250 degree temperature range between day and night, and the day/night cycles are 2 weeks long each, meaning your rover gets really hot soaked alternating with really cold soaked. Martian day/night temperatures are not so extreme, and the days/nights are only about 12-1/4 hours long each. The atmosphere helps moderate the temperature.
Sure, Mars has winds where Luna doesn't, but given the thin atmosphere, it's not like you have to worry about them blowing the rover away or anything. As it turned out, they were just right to blow accumulated dust off the solar panels. Yes, the wind means dust might be more likely to get into the mechanisms, but at least it's smooth rounded dust. Lunar dust is jagged fractal surfaces all the way down, highly abrasive; the saving grace is that it only gets kicked up by your wheels spinning or a nearby impact. (That's another difference -- the Martian atmosphere is enough that you don't have to worry about micrometeorite impacts, which you do on the Moon.)
Venus is of course a different question; nobody's gotten a Venus-lander to last for more than a few hours. The surface temperature is twice as hot as a pizza oven (hotter, in fact, than Mercury's surface), and the pressure is about the same as 3000 feet underwater.
I'm not really impressed by Constellation, least of all by the Ares I configuration. Putting a hammerhead (known to cause dynamic instability problems) on top of a single stick solid booster (known to be somewhat uncontrollable once lit) seems to me to be asking for trouble. At least they've put a launch escape rocket on the thing.
Personally I'd rather see something fully reusable, by which I don't mean crash'n'salvage like the SRBs. Ideally a VTOVL SSTO if they can do it (don't give me "physically impossible", because it's not; it is a difficult engineering problem though), otherwise two stage with recovery modes throughout the launch profile (like the original F-1 Flyback booster proposed for Shuttle -- or White Knight/Spaceship 1 scaled up to something orbital).
On the other hand, Constellation makes a nice dinosaur farm to keep NASA and Big Aerospace out of the hair of people who are seriously trying to get the job done.
if we ever land a man on a planet large enough to sustain an earth-like atmosphere, the chances of ever having them return is nil.
Nonsense, we've done it a few times already. For example, Gordon Cooper flew in space for over 34 hours, landed on a planet large enough to sustain a very earth-like atmosphere, and returned to space just over two years later, spending another 8 days in space before landing on Earth. Granted, he did have the help of some of the local inhabitants to get back into space again, and it wasn't in the same spacecraft.
In fact, what current trends suggest if anything is that it's vehicle complexity and reliability that matter more than anything, and being able to get a simple, robust vehicle off the ground repeatedly and on schedule, again and again, matter more than anything else in terms of keeping your per-launch costs down.
What costs the money is the standing army you need for a launch crew (including vehicle assembly crew, etc). The propellants are cheap, and even the hardware isn't that expensive, especially if you can amortize the launch vehicle hardware cost over multiple launches. (Which, of course, you can't do with disposables.)
So yes, design your LVs with adequate engineering margins that you don't have to test them up the wazoo before flight, in fact you can test by flying. Design them with recoverability built into the launch profile so that if something does go wrong, you just land the thing and fix it. Design them to land and be turned around withought having to be partially disassembled and completely overhauled. And design the support systems to only need a few people, not thousands.
In other words, design the damn things to be transportation, like jets, not ammunition, like ICBMs.
BTW, for the record, lunar injection actually requires less delta-vee than a geostationary orbit does. The apogee is higher for lunar injection, but you don't need to also raise the perigee 22,000 miles.
No, the spacetime curve occurs first. Sometimes matter (which has mass) collects in these curved spacetime pockets. Now, astronomers have determined that there's more gravity out there than can be accounted for by observable matter, so they invented "dark matter". Really it's just pockets of curved spacetime that haven't collected enough matter to be noticeable.
As for why it's curved in the first place..well, why wouldn't it be? Why would the flatness of spacetime be any more uniform than the big-bang ~3K background radiation is?
(And yes, I just made all this stuff up, but it wouldn't surprise me if someone else has already suggested it.)
As I recall, a lot of companies who'd forked over lots of dollars for multi-year support agreements back around 2001 (there was some marketing phrase, I forget what) were starting to grumble that the promised new releases included in the price hadn't yet been released, and the agreements were about to expire.
This is one of the factors that prompted the early release of the "business" version of Vista in late 2006 instead of it being released along with the home version in early 2007.
Not that any businesses really wanted to touch that, but it let Microsoft say they'd lived up to their part of the agreement (in their own inimitable (innovative?) Microsoft way, of course).
You raise a valid point about several factors coming together. I am (or rather, have been) both a pilot and a scuba diver, and I've attended safety seminars in both fields. One thing fairly constant in fatal accidents -- more than one thing went wrong, and if the pilot/diver had called a halt at the first -- or even the second -- thing, they'd still be alive. The thing is, we all tend to build up a body of experience that tells us that "just one thing" being wrong won't hurt. Like one of my boys, when I advise him against the risky behaviour he's engaging in, "well, I haven't fallen/broken it/whatever yet".
With both Challenger and Columbia there was evidence that they'd seen similar problems (O-ring blowby and ice damage to tiles) though on a lesser scale on earlier flights. One wonders how much that built up a degree of complacency rather than concern. "It hasn't been a problem yet."
The engineering part was originally flawed in that it could not be built as designed. That three story rod wasn't threaded its entire length in the original design, it was just threaded where the bolt attached. Looked good on paper, darn near impossible to fabricate. That said, though, it would probably have worked if the entire length had been threaded (although threading adds its own set of problems).
It's hysterical. I'd never seen it before, but now I have a new time sink (oh, joy) as I wade through the archives. Lots of bad puns (Dresden Codak? right) in-jokes, and great artwork (love the Paul (Muadib) Atreides and Morloks in the very first cartoon).
Yeah, maybe you need to turn in your geek cred. Or get your head out of a programming manual and into something else once in a while.
I take that back there are two things about driving in the UK, the second is do you people believe in F'ing street/road signs?
Nah. It's a holdover from WW II, when they took down all the road signs to confuse the enemy if Hitler had landed an invasion force. I think that's also why none of the roads run in a straight line for more than a mile and why none of them meet at 90-degree angles.
Yes, wood's a good way to store CO2. I store mine as paper, in books.;-)
Alternatively, just liquifying CO2 (not hard, the triple point is at about 75psi) will reduce the volume by about 600 times. I.e. a one-litre tank of liquid CO2 (about 1.18 kg CO2) holds about 600 l of gaseous CO2 at STP. That's more than 7 times better than the magic crystals.
tidal power generation systems haven't been perfected yet.
No power generation system has been "perfected". It doesn't have to be perfect to generate useful power -- and there are quite a few tidal power generations systems that are producing commercial power. Not that the GP post mentioned "tidal" power per se, just "ocean driven", which could also include things like wave driven, OTEC, deep currents, etc.
Mars is a big ball of dust with little atmosphere, no magnetosphere, no water...
Please stop already with displaying your abysmal ignorance. Mars has the largest (though now exinct) volcano in the solar system (Olympus Mons, along with three nearly as big on Tharsis). You don't get those on a "ball of dust". Sure, there may not be much magnetosphere at the moment -- Earth has had periods like that too, during geomagnetic reversals. There's still life here.
As for water...if you don't believe the photographs, go get yourself a decent telescope and just take a look at Mars. See that white patch at the pole? That's ice, also known as frozen water. (Yeah, the winter icecap also gets some CO2 ice; the permanent cap is water ice.)
Perhaps Mars never did have life. But your analogy is like the guy who goes looking for his dropped keys under the lamppost because the light there is better than where he dropped them. We haven't begun to look in the really interesting places yet.
Presumably something illegal has been done otherwise the police wouldn't be involved.
That's a mighty big presumption.
It could be a jealous cop tracking down a note sent to his girlfriend.
Or it could be some politician pushing willing cops to track down the source of some otherwise anonymous flyers opposing that politician or his policies.
No doubt the telcos that are currently desperately seeking immunity from certain lawsuits just presumed something illegal was going on or the feds wouldn't be involved in asking for wiretaps. (Well, there was -- the wiretaps themselves.) If there's a legitimate reason for asking -- either for printer codes or wiretaps -- then the authorities should have no problem getting a warrant for that.
P.S. - If you can get some, print a color page on black paper (preferably semi-gloss), the dots stand out really well
They stand out just fine on white paper under blue light, as one of the EFF pages illustrates.
1. Every color laser printer made in the last 10 years from every manufacturer that I have ever encountered uses the "yellow dots" tagging.
Then I guess you haven't encountered HP 4500 or HP 8500 series printers (maybe they don't need to be repaired as much?). One of the other EFF pages lists a number of other printer models that don't use yellow dots (which isn't to say that they don't use some other kind of tagging).
You can learn a lot from a busted piece of machinery.
Heh, or not. One of the things Britain did during WW II was to leave bits of busted machinery (electronics) that not only never worked, but were designed to be deliberately misleading, at the occasional aircraft crash site in German-occupied territory. The idea was to keep German radar scientists, etc, busy chasing down wrong paths if/when they recovered the equipment. (Which they did; recovering any kind of radar-related gear from Allied aircraft was a high priority for them.)
Microcenter is pretty good in my experience -- the prices are often better than any other brick'n'mortar, I've had no hassle returning stuff, and returned stuff that they do re-sell is clearly marked as such and discounted.
That said, I'm sure somebody will pipe up with a bad experience they've had. No place is perfect, but some are definitely worse than others. (They also don't have a lot of stores, but they are occasionally opening new ones, more than can be said for some of the others.)
Slashdot Mirror
Shouldn't Linux not break their ABI with every new kernel release?
Linux doesn't. The Applications Binary Interface is remarkably stable in Linux, all things considered. The kernel internal interface is of course fair game, since it's all source code anyway (a few vendors' proprietary drivers notwithstanding). I've got 2.4.x application binaries that work just fine on 2.6.x.
Predictable doesn't mean easy. Lunar temperatures have something like a +/- 250 degree temperature range between day and night, and the day/night cycles are 2 weeks long each, meaning your rover gets really hot soaked alternating with really cold soaked. Martian day/night temperatures are not so extreme, and the days/nights are only about 12-1/4 hours long each. The atmosphere helps moderate the temperature.
Sure, Mars has winds where Luna doesn't, but given the thin atmosphere, it's not like you have to worry about them blowing the rover away or anything. As it turned out, they were just right to blow accumulated dust off the solar panels. Yes, the wind means dust might be more likely to get into the mechanisms, but at least it's smooth rounded dust. Lunar dust is jagged fractal surfaces all the way down, highly abrasive; the saving grace is that it only gets kicked up by your wheels spinning or a nearby impact. (That's another difference -- the Martian atmosphere is enough that you don't have to worry about micrometeorite impacts, which you do on the Moon.)
Venus is of course a different question; nobody's gotten a Venus-lander to last for more than a few hours. The surface temperature is twice as hot as a pizza oven (hotter, in fact, than Mercury's surface), and the pressure is about the same as 3000 feet underwater.
Dude, you really need to start thinking about shorter variable, or rather method, names.
much like the broadcast TV industry adopted the BetaMax format for use in advanced video editing,
No, they didn't. The TV industry adopted BetaCam, not BetaMax. The technologies aren't compatible.
I'm not really impressed by Constellation, least of all by the Ares I configuration. Putting a hammerhead (known to cause dynamic instability problems) on top of a single stick solid booster (known to be somewhat uncontrollable once lit) seems to me to be asking for trouble. At least they've put a launch escape rocket on the thing.
Personally I'd rather see something fully reusable, by which I don't mean crash'n'salvage like the SRBs. Ideally a VTOVL SSTO if they can do it (don't give me "physically impossible", because it's not; it is a difficult engineering problem though), otherwise two stage with recovery modes throughout the launch profile (like the original F-1 Flyback booster proposed for Shuttle -- or White Knight/Spaceship 1 scaled up to something orbital).
On the other hand, Constellation makes a nice dinosaur farm to keep NASA and Big Aerospace out of the hair of people who are seriously trying to get the job done.
if we ever land a man on a planet large enough to sustain an earth-like atmosphere, the chances of ever having them return is nil.
;-)
Nonsense, we've done it a few times already. For example, Gordon Cooper flew in space for over 34 hours, landed on a planet large enough to sustain a very earth-like atmosphere, and returned to space just over two years later, spending another 8 days in space before landing on Earth. Granted, he did have the help of some of the local inhabitants to get back into space again, and it wasn't in the same spacecraft.
Quite a few others made similar trips.
In fact, what current trends suggest if anything is that it's vehicle complexity and reliability that matter more than anything, and being able to get a simple, robust vehicle off the ground repeatedly and on schedule, again and again, matter more than anything else in terms of keeping your per-launch costs down.
What costs the money is the standing army you need for a launch crew (including vehicle assembly crew, etc). The propellants are cheap, and even the hardware isn't that expensive, especially if you can amortize the launch vehicle hardware cost over multiple launches. (Which, of course, you can't do with disposables.)
So yes, design your LVs with adequate engineering margins that you don't have to test them up the wazoo before flight, in fact you can test by flying. Design them with recoverability built into the launch profile so that if something does go wrong, you just land the thing and fix it. Design them to land and be turned around withought having to be partially disassembled and completely overhauled. And design the support systems to only need a few people, not thousands.
In other words, design the damn things to be transportation, like jets, not ammunition, like ICBMs.
BTW, for the record, lunar injection actually requires less delta-vee than a geostationary orbit does. The apogee is higher for lunar injection, but you don't need to also raise the perigee 22,000 miles.
Argh. Slashdot ate my letter 'nu'. It was right there after the 'h' for Planck's constant, honest.
But, [photons] don't "cause" gravity, because they do not attract other objects.
Whoever told you this was lying or mistaken. Just because they don't exert very much gravitational force doesn't mean they exert none at all.
Want to figure the effective mass of a photon? Determine its energy (from frequency, E=h) and you can determine the mass (m=E/c^2).
No, the spacetime curve occurs first. Sometimes matter (which has mass) collects in these curved spacetime pockets. Now, astronomers have determined that there's more gravity out there than can be accounted for by observable matter, so they invented "dark matter". Really it's just pockets of curved spacetime that haven't collected enough matter to be noticeable.
As for why it's curved in the first place..well, why wouldn't it be? Why would the flatness of spacetime be any more uniform than the big-bang ~3K background radiation is?
(And yes, I just made all this stuff up, but it wouldn't surprise me if someone else has already suggested it.)
Photons aren't supposed to have mass
No, photons don't have rest mass -- but then, they're never at rest. While they're moving, they have energy, and therefore mass (just not very much).
Okay, thanks for that clarification; it sort of confirms that the Software Assurance licenses were another factor driving that deadline.
As I recall, a lot of companies who'd forked over lots of dollars for multi-year support agreements back around 2001 (there was some marketing phrase, I forget what) were starting to grumble that the promised new releases included in the price hadn't yet been released, and the agreements were about to expire.
This is one of the factors that prompted the early release of the "business" version of Vista in late 2006 instead of it being released along with the home version in early 2007.
Not that any businesses really wanted to touch that, but it let Microsoft say they'd lived up to their part of the agreement (in their own inimitable (innovative?) Microsoft way, of course).
Well, as I said, threading adds its own problems.
You raise a valid point about several factors coming together. I am (or rather, have been) both a pilot and a scuba diver, and I've attended safety seminars in both fields. One thing fairly constant in fatal accidents -- more than one thing went wrong, and if the pilot/diver had called a halt at the first -- or even the second -- thing, they'd still be alive. The thing is, we all tend to build up a body of experience that tells us that "just one thing" being wrong won't hurt. Like one of my boys, when I advise him against the risky behaviour he's engaging in, "well, I haven't fallen/broken it/whatever yet".
With both Challenger and Columbia there was evidence that they'd seen similar problems (O-ring blowby and ice damage to tiles) though on a lesser scale on earlier flights. One wonders how much that built up a degree of complacency rather than concern. "It hasn't been a problem yet."
The engineering part was originally flawed in that it could not be built as designed. That three story rod wasn't threaded its entire length in the original design, it was just threaded where the bolt attached. Looked good on paper, darn near impossible to fabricate. That said, though, it would probably have worked if the entire length had been threaded (although threading adds its own set of problems).
It's hysterical. I'd never seen it before, but now I have a new time sink (oh, joy) as I wade through the archives. Lots of bad puns (Dresden Codak? right) in-jokes, and great artwork (love the Paul (Muadib) Atreides and Morloks in the very first cartoon).
Yeah, maybe you need to turn in your geek cred. Or get your head out of a programming manual and into something else once in a while.
I take that back there are two things about driving in the UK, the second is do you people believe in F'ing street/road signs?
Nah. It's a holdover from WW II, when they took down all the road signs to confuse the enemy if Hitler had landed an invasion force. I think that's also why none of the roads run in a straight line for more than a mile and why none of them meet at 90-degree angles.
Yes, wood's a good way to store CO2. I store mine as paper, in books. ;-)
Alternatively, just liquifying CO2 (not hard, the triple point is at about 75psi) will reduce the volume by about 600 times. I.e. a one-litre tank of liquid CO2 (about 1.18 kg CO2) holds about 600 l of gaseous CO2 at STP. That's more than 7 times better than the magic crystals.
tidal power generation systems haven't been perfected yet.
No power generation system has been "perfected". It doesn't have to be perfect to generate useful power -- and there are quite a few tidal power generations systems that are producing commercial power. Not that the GP post mentioned "tidal" power per se, just "ocean driven", which could also include things like wave driven, OTEC, deep currents, etc.
Mars is a big ball of dust with little atmosphere, no magnetosphere, no water...
Please stop already with displaying your abysmal ignorance. Mars has the largest (though now exinct) volcano in the solar system (Olympus Mons, along with three nearly as big on Tharsis). You don't get those on a "ball of dust". Sure, there may not be much magnetosphere at the moment -- Earth has had periods like that too, during geomagnetic reversals. There's still life here.
As for water...if you don't believe the photographs, go get yourself a decent telescope and just take a look at Mars. See that white patch at the pole? That's ice, also known as frozen water. (Yeah, the winter icecap also gets some CO2 ice; the permanent cap is water ice.)
Perhaps Mars never did have life. But your analogy is like the guy who goes looking for his dropped keys under the lamppost because the light there is better than where he dropped them. We haven't begun to look in the really interesting places yet.
And you know this how, exactly?
What's your explanation of Viking's labelled release experiment? Were you even aware that there was something that needed explaining?
Presumably something illegal has been done otherwise the police wouldn't be involved.
That's a mighty big presumption.
It could be a jealous cop tracking down a note sent to his girlfriend.
Or it could be some politician pushing willing cops to track down the source of some otherwise anonymous flyers opposing that politician or his policies.
No doubt the telcos that are currently desperately seeking immunity from certain lawsuits just presumed something illegal was going on or the feds wouldn't be involved in asking for wiretaps. (Well, there was -- the wiretaps themselves.) If there's a legitimate reason for asking -- either for printer codes or wiretaps -- then the authorities should have no problem getting a warrant for that.
P.S. - If you can get some, print a color page on black paper (preferably semi-gloss), the dots stand out really well
They stand out just fine on white paper under blue light, as one of the EFF pages illustrates.
1. Every color laser printer made in the last 10 years from every manufacturer that I have ever encountered uses the "yellow dots" tagging.
Then I guess you haven't encountered HP 4500 or HP 8500 series printers (maybe they don't need to be repaired as much?). One of the other EFF pages lists a number of other printer models that don't use yellow dots (which isn't to say that they don't use some other kind of tagging).
You can learn a lot from a busted piece of machinery.
Heh, or not. One of the things Britain did during WW II was to leave bits of busted machinery (electronics) that not only never worked, but were designed to be deliberately misleading, at the occasional aircraft crash site in German-occupied territory. The idea was to keep German radar scientists, etc, busy chasing down wrong paths if/when they recovered the equipment. (Which they did; recovering any kind of radar-related gear from Allied aircraft was a high priority for them.)
Microcenter is pretty good in my experience -- the prices are often better than any other brick'n'mortar, I've had no hassle returning stuff, and returned stuff that they do re-sell is clearly marked as such and discounted.
That said, I'm sure somebody will pipe up with a bad experience they've had. No place is perfect, but some are definitely worse than others. (They also don't have a lot of stores, but they are occasionally opening new ones, more than can be said for some of the others.)