It's worth noting that an F-16 also has one hell of a lot of thrust. So much so, that it can fly with one wing. You're not going to get that kind of performance out of a Cessna or Moller skycar. Thus your run of the mill pilot has to be a bit more deliberate in his use of control surfaces.
(Can anyone imagine a Cessna performing an inverted flight like the one in Top Gun? You wouldn't be getting a good Polaroid, that's for sure!)
Getting on and off the ground is not as much a problem with the Moller M400 Skycar is a VTOL aircraft with complete computer control.
Actually, that *was* the plan. The final model is actually Short Take Off and Landing (STOL) because it doesn't have enough thrust to maintain hovered flight. Even if it were VTOL, high winds could still blow it around like a kite, making landings just as dangerous as ever.
Wouldn't having a vehicle with less wing area minimize this? Of course that means it needs more thrust, implying that moller is on the right track assuming he's not just a troll.
Actually, I do like Moller's design. As I said, his biggest problem is that he doesn't have enough thrust. For what he's doing, any sort of prop engine (he uses turbofans IIRC) probably won't be sufficient. He needs something more along the lines of a gas turbine, a.k.a. a jet engine. Of course, a jet engine would complicate his control surfaces since they'd suddenly be required to deflect high temperatures without corroding or melting.
This, too, can be solved through the use of an intelligent control system.
Yes, intelligent control systems would help. Unfortunately, they'd also reduce the pilot's ability to fly the craft. It's a bit like if we gave a car a throttle instead of gas and brake pedals. Sure, the car could act intelligently and accelerate/decelerate you based on your throttle setting. But it could never handle complex maneuvers that are sometimes required in an emergency situation. (Many of which we take for granted because of the control we have.)
Current planes are like ancient DOS systems, where you have to type in huge commands, and any mistake is catastrophic.
Bullocks. A modern 777 will keep itself in the air, with or without you. It's airframe is designed such that it WANTS to fly. Try executing a deadly maneuver in X-Plane sometime, using nothing to correct your flight except thrust. The 777 will right itself without much problem. It will probably even climb until it reaches equilibrium.
You don't worry about stabilization, the computer does.
Airframes are usually *designed* to be stable. Especially something like a CS-150 with the wing tips for stabilization. Your real problems with any flight are:
1. Preventing midair collisions. 2. Getting on and off the ground.
The first will become a BIG problem if everyone gets their "flying car". The second one is a big problem, period. Getting off the ground usually isn't so big of a problem as long as you give yourself as much room as possible. Getting on the ground IS a big problem.
When you're flying through the air, your path is determined by the gasses through which you're passing. This can cause your path to skew, and can even result in some roll. The problem is that the ground is NOT moving. Thus you have to attempt to compensate. If you see a plane coming that looks like it's crooked, the pilot is probably NOT drunk. He's compensating. Yet even the best pilots occasionally have a hard landing. Go shopping for a plane sometime, and you'll notice that quite a few of them talk about replacing or repairing the firewall after a hard landing.
Much better to have something where you tell it via some 3D joystic, "Go up, down, left, right, forward, backward", end of story.
You can't go left or right. This isn't a car. You have to roll and execute a banking maneuver. A computer can simplify this, but you can't change the physics of flight. (Again, with "flight" defined as "obtaining lift by passing through the atmosphere" A hovercraft can obviously thrust in any direction it damn well pleases.)
You don't worry about stabilization, the computer does.
Keep in mind that you can only stabilize the craft so much. If it's light, it WILL bounce on thermals and downdrafts. There's very little the computer can do about this other than to make course corrections. The last thing we need is some guy freaking out at a thermal, accidently rolling his plane, getting disoriented, and taking her into the ground.
I do use Mozilla/FireFox. My point is that I'm not going to applaud them for having a boneheaded idea of what "security" means.
Re:I'm sorry, were you expecting better?
on
XP2 Spotted In The Wild
·
· Score: 2, Insightful
The meta tag appeared to begin with, because HTML authors often don't have access to the web server. This is a very valid reason, and I can guarantee you that authors would just start writing "window.location = 'xyz.html'" to get around it. Thus Microsoft has saved us from nothing, and made everyone's lives more difficult.
There's an old Garfield comic that I find to be true of cats. Jon walks through the door, and trips over Garfield. Jon yells at Garfield to go somewhere else. Jon picks up his groceries, starts walking, and trips over Garfield in another spot. Again, he yells at Garfield to move. Garfield moves, and predictably, Jon trips over him again. In the panel we see Garfield smacking his forehead in frustration. The lesson? Cats always position themselves in the worst space possible.
I talked to my wife a bit on why they do that, and her opinion is that they want to be the center of attention. By putting themselves in your path, they make sure that you notice them and that they don't miss anything exciting. Or maybe they're just making sure you don't run away.;-)
Last I heard, he was still at it. Unfortunately, his final design is woefully underpowered, and has several stability problems he's trying to solve.
Speaking of which, that's a big problem I see with giving people flying cars. Flying (in the sense of using wings to generate lift) is VERY different from driving. For example, most people don't know that you have to nudge the stick, then move it back into a straight position to properly execute a bank. The bank will continue until you nudge the stick back the other way, and force the plane to level.
Even worse is the shear number of control surfaces that are completely unnatural to a driver. You can't just move the stick. That will cause the plane to slide. You have to give it some rudder. I'm not even going to go into how queasy bouncing on thermals is going to make most people.
To make an aircraft stable enough for the average driver, you're going to need something with a LOT of thrust. (i.e. Apply enough thrust to a brick, and it will fly.) Maneuvering would need to be handled by computer control to simplify the procedure.
Of course, we could just get everyone to obtain a pilot's license. But then I'd truly FEAR for the safety of the skyways.
Re:I'm sorry, were you expecting better?
on
XP2 Spotted In The Wild
·
· Score: 4, Insightful
Personally, I would applaud more if their idea of security wasn't so damned screwy. For example, XP SP2 now modifies IE to reject redirects. i.e. If you have a redirect page to forward someone to your new website, IE will pop up an error message and tell you that it won't redirect. To make the redirect work, you have to add the site to your list of trusted sites. Apparently, there is no way to turn off this behavior.
If Microsoft would focus on *real* security like that found in FireFox, OS X, etc., they wouldn't have to put these stupid "security" enhancements in. On the bright side, Microsoft is making Macs veeerrrry attractive to end users.
As I said, it's as clear as mud. You've basically got two groups who are really just part of the same process. Now they've decided to split into two pieces. It's all very confusing. =/
Q: You know the only thing more vile and evil than Clippy?
A: The IT color scheme on Slashdot.
Re:who forked from who..
on
The Power of X
·
· Score: 5, Informative
As I understand it, you're right on the first part. XFree86 did fork X.org's work. The part that you're wrong on is that X.org didn't use XFree86's code. XFree86 was a fork specifically designed for the x86 platform. X.org didn't have that, and thus had to patch their codebase from XFree86's codebase.
I think you're confusing Holographic imaging with holographic data storage. Holographic data storage works by stacking layers of media, with each layer sensitive to only one area of the spectrum. All other spectrums pass through to the next layer down. This allows you to "stack" information like hard drive disk platters.
Thank you for taking the time to type up this response, and for providing a more balanced viewpoint. You were my first and only enemy, but that has now been reversed. It takes a big man to admit when he's wrong. Thank you.
A few comments:
However I stand by that Java is not as efficient as other Languages. I stand by that Java slow JVM startup is an indication to not being best.
I think the difficulty that most people have here, is that Java runs on a virtual machine. What that means is that the Java VM should really be running as an OS component rather than a userland program. Unfortuntately, Java development was blocked by Microsoft very early in the game, so we have the sorts of VMs you see today. Sun gets around this problem on JDS by preloading JVMs, then distributing them as needed.
Another nitpick but I would not consider Perl and Python in a category of silly scripting languages. They both are cross platform. Both have a variety of libs (Perl's CPAN is unsurpassed).
Actually, I said "simple", not "silly". Perl and Python are designed to be scripting interpreters, and thus focus heavily on sacrificing performance for startup time. Thus they are really in a different class than Java.
However, it is worth noting that because the Java platform is a virtual machine, it is quite possible to create a Java based shell. Inside such a shell, scripts may start as fast (sometimes faster!) than equivalent Unix scripts. I have a project on my hard drive that reimplements the Unix environment in Java (including full telnet support). The performance characteristics of such a design are comparable to that of a normal Unix environment.
Or are you saying that C programmers are the best to write lousy code and that non C programmers can write better Java code than C prgrammers? I find your claim that its C programmers that are to blame hard to swallow.
Actually, my point was that C/C++ programmers tend to evaluate Java's performance by writing 10 lines of poor quality code (because they haven't learned the language/platform yet), then use the results as evidence of Java's poor performance.
The truly amusing part is that the Java community originally was populated and promoted by C/C++ programmers. Back in the early days of Java, we were so impressed with the platform that we switched over in spite of many of the performance issues of the time! Keep in mind that C programmers are always taught that performance is king. To make a switch like that meant that Java was a very compelling platform!
Most of the C/C++ programmers who didn't make the migration now talk about all the wonderful libraries they have that compare favorably to Java's APIs. Which is quite amusing given that Java's existence is what pushed these libraries into existence!
String x = ' Hello ' ; x = x + ' world ';
because when executed its the same as:
String x = ' Hello ' ; x = x.clone().concat (' world ');
its slow, + operator returns new instance of String, old goes to garbage collection. Now lets do it the clean proper Java way:
String x = ' Hello ' ; x.concat (' world ');
Just a minor correction.
String x = " Hello "; x = x + " world ";
produces:
String x = " Hello ";//Reference to static class resource x = new StringBuffer(x).append(" world ").toString();
A more efficient way is:
StringBuffer buffer = new StringBuffer(" Hello "); String x; buffer.append(" world "); x = buffer.toString();
Of course, in the case you listed, the performance difference is minor. It really only makes a difference when you're concatonating large strings, or performing parsing operations.
ouch, was this really necessary?
Given your apology, I do feel bad about my rather blunt manner. However, you do have to admit that you had it coming. In attempting to bait responders b
Actually, I did say that I wouldn't mind if Linux broke binary compatibility between major versions (i.e. 2.2 -> 2.4) However, it's obviously best if compatability is maintained.
To be perfectly clear, I'm not saying that Open Source drivers should go away. Many of them are very useful and should be preferred over any commercial driver. However, the number of devices for which Linux can never possibly keep up (scanners, cameras, MP3 players, NICs, 3D Accelerators, etc.) should be allowed to distribute binary drivers. That would make sure that you could at least get your hardware to work in the first place, rather than waiting a year or two for support.
But data rates on hard drives DO increase with more heads. This holographic storage is designed to act like multiple heads. Since the data is "stacked", you can read more on a single pass. My 11GB may not be correct, but neither is the assertion that the speed would be ~200MB/sec.
It's been out of print for a long time. They recently began printing it again. Thus, "lost masterpiece".:-)
Don't worry, you're the third person to ask that. Besides, it's good for the average Slashdotter to know that Asimov wrote something OTHER than the robot series.
Slashdot Mirror
Doh! Scratch that. It was an F-15 that flew with one wing. My point still holds about an FF-15 having lots more thrust, though.
Doh! Scratch that. It was an F-15 that flew with one wing. My point still holds about lots more thrust, though.
It's worth noting that an F-16 also has one hell of a lot of thrust. So much so, that it can fly with one wing. You're not going to get that kind of performance out of a Cessna or Moller skycar. Thus your run of the mill pilot has to be a bit more deliberate in his use of control surfaces.
(Can anyone imagine a Cessna performing an inverted flight like the one in Top Gun? You wouldn't be getting a good Polaroid, that's for sure!)
So THATS what drinkypoo was talking about. That's actually pretty funny.
Getting on and off the ground is not as much a problem with the Moller M400 Skycar is a VTOL aircraft with complete computer control.
Actually, that *was* the plan. The final model is actually Short Take Off and Landing (STOL) because it doesn't have enough thrust to maintain hovered flight. Even if it were VTOL, high winds could still blow it around like a kite, making landings just as dangerous as ever.
Wouldn't having a vehicle with less wing area minimize this? Of course that means it needs more thrust, implying that moller is on the right track assuming he's not just a troll.
Actually, I do like Moller's design. As I said, his biggest problem is that he doesn't have enough thrust. For what he's doing, any sort of prop engine (he uses turbofans IIRC) probably won't be sufficient. He needs something more along the lines of a gas turbine, a.k.a. a jet engine. Of course, a jet engine would complicate his control surfaces since they'd suddenly be required to deflect high temperatures without corroding or melting.
This, too, can be solved through the use of an intelligent control system.
Yes, intelligent control systems would help. Unfortunately, they'd also reduce the pilot's ability to fly the craft. It's a bit like if we gave a car a throttle instead of gas and brake pedals. Sure, the car could act intelligently and accelerate/decelerate you based on your throttle setting. But it could never handle complex maneuvers that are sometimes required in an emergency situation. (Many of which we take for granted because of the control we have.)
Current planes are like ancient DOS systems, where you have to type in huge commands, and any mistake is catastrophic.
Bullocks. A modern 777 will keep itself in the air, with or without you. It's airframe is designed such that it WANTS to fly. Try executing a deadly maneuver in X-Plane sometime, using nothing to correct your flight except thrust. The 777 will right itself without much problem. It will probably even climb until it reaches equilibrium.
You don't worry about stabilization, the computer does.
Airframes are usually *designed* to be stable. Especially something like a CS-150 with the wing tips for stabilization. Your real problems with any flight are:
1. Preventing midair collisions.
2. Getting on and off the ground.
The first will become a BIG problem if everyone gets their "flying car". The second one is a big problem, period. Getting off the ground usually isn't so big of a problem as long as you give yourself as much room as possible. Getting on the ground IS a big problem.
When you're flying through the air, your path is determined by the gasses through which you're passing. This can cause your path to skew, and can even result in some roll. The problem is that the ground is NOT moving. Thus you have to attempt to compensate. If you see a plane coming that looks like it's crooked, the pilot is probably NOT drunk. He's compensating. Yet even the best pilots occasionally have a hard landing. Go shopping for a plane sometime, and you'll notice that quite a few of them talk about replacing or repairing the firewall after a hard landing.
Much better to have something where you tell it via some 3D joystic, "Go up, down, left, right, forward, backward", end of story.
You can't go left or right. This isn't a car. You have to roll and execute a banking maneuver. A computer can simplify this, but you can't change the physics of flight. (Again, with "flight" defined as "obtaining lift by passing through the atmosphere" A hovercraft can obviously thrust in any direction it damn well pleases.)
You don't worry about stabilization, the computer does.
Keep in mind that you can only stabilize the craft so much. If it's light, it WILL bounce on thermals and downdrafts. There's very little the computer can do about this other than to make course corrections. The last thing we need is some guy freaking out at a thermal, accidently rolling his plane, getting disoriented, and taking her into the ground.
Did someone mention orbiting Winnebagos? Keep firing assholes!!!
(Apologies to those who've never seen SpaceBalls.)
I do use Mozilla/FireFox. My point is that I'm not going to applaud them for having a boneheaded idea of what "security" means.
The meta tag appeared to begin with, because HTML authors often don't have access to the web server. This is a very valid reason, and I can guarantee you that authors would just start writing "window.location = 'xyz.html'" to get around it. Thus Microsoft has saved us from nothing, and made everyone's lives more difficult.
There's an old Garfield comic that I find to be true of cats. Jon walks through the door, and trips over Garfield. Jon yells at Garfield to go somewhere else. Jon picks up his groceries, starts walking, and trips over Garfield in another spot. Again, he yells at Garfield to move. Garfield moves, and predictably, Jon trips over him again. In the panel we see Garfield smacking his forehead in frustration. The lesson? Cats always position themselves in the worst space possible.
;-)
I talked to my wife a bit on why they do that, and her opinion is that they want to be the center of attention. By putting themselves in your path, they make sure that you notice them and that they don't miss anything exciting. Or maybe they're just making sure you don't run away.
Last I heard, he was still at it. Unfortunately, his final design is woefully underpowered, and has several stability problems he's trying to solve.
Speaking of which, that's a big problem I see with giving people flying cars. Flying (in the sense of using wings to generate lift) is VERY different from driving. For example, most people don't know that you have to nudge the stick, then move it back into a straight position to properly execute a bank. The bank will continue until you nudge the stick back the other way, and force the plane to level.
Even worse is the shear number of control surfaces that are completely unnatural to a driver. You can't just move the stick. That will cause the plane to slide. You have to give it some rudder. I'm not even going to go into how queasy bouncing on thermals is going to make most people.
To make an aircraft stable enough for the average driver, you're going to need something with a LOT of thrust. (i.e. Apply enough thrust to a brick, and it will fly.) Maneuvering would need to be handled by computer control to simplify the procedure.
Of course, we could just get everyone to obtain a pilot's license. But then I'd truly FEAR for the safety of the skyways.
Personally, I would applaud more if their idea of security wasn't so damned screwy. For example, XP SP2 now modifies IE to reject redirects. i.e. If you have a redirect page to forward someone to your new website, IE will pop up an error message and tell you that it won't redirect. To make the redirect work, you have to add the site to your list of trusted sites. Apparently, there is no way to turn off this behavior.
If Microsoft would focus on *real* security like that found in FireFox, OS X, etc., they wouldn't have to put these stupid "security" enhancements in. On the bright side, Microsoft is making Macs veeerrrry attractive to end users.
As I said, it's as clear as mud. You've basically got two groups who are really just part of the same process. Now they've decided to split into two pieces. It's all very confusing. =/
Q: You know the only thing more vile and evil than Clippy?
A: The IT color scheme on Slashdot.
As I understand it, you're right on the first part. XFree86 did fork X.org's work. The part that you're wrong on is that X.org didn't use XFree86's code. XFree86 was a fork specifically designed for the x86 platform. X.org didn't have that, and thus had to patch their codebase from XFree86's codebase.
Clear as mud?
I think you're confusing Holographic imaging with holographic data storage. Holographic data storage works by stacking layers of media, with each layer sensitive to only one area of the spectrum. All other spectrums pass through to the next layer down. This allows you to "stack" information like hard drive disk platters.
Thank you for taking the time to type up this response, and for providing a more balanced viewpoint. You were my first and only enemy, but that has now been reversed. It takes a big man to admit when he's wrong. Thank you.
;
;
//Reference to static class resource
A few comments:
However I stand by that Java is not as efficient as other Languages. I stand by that Java slow JVM startup is an indication to not being best.
I think the difficulty that most people have here, is that Java runs on a virtual machine. What that means is that the Java VM should really be running as an OS component rather than a userland program. Unfortuntately, Java development was blocked by Microsoft very early in the game, so we have the sorts of VMs you see today. Sun gets around this problem on JDS by preloading JVMs, then distributing them as needed.
Another nitpick but I would not consider Perl and Python in a category of silly scripting languages. They both are cross platform. Both have a variety of libs (Perl's CPAN is unsurpassed).
Actually, I said "simple", not "silly". Perl and Python are designed to be scripting interpreters, and thus focus heavily on sacrificing performance for startup time. Thus they are really in a different class than Java.
However, it is worth noting that because the Java platform is a virtual machine, it is quite possible to create a Java based shell. Inside such a shell, scripts may start as fast (sometimes faster!) than equivalent Unix scripts. I have a project on my hard drive that reimplements the Unix environment in Java (including full telnet support). The performance characteristics of such a design are comparable to that of a normal Unix environment.
Or are you saying that C programmers are the best to write lousy code and that non C programmers can write better Java code than C prgrammers? I find your claim that its C programmers that are to blame hard to swallow.
Actually, my point was that C/C++ programmers tend to evaluate Java's performance by writing 10 lines of poor quality code (because they haven't learned the language/platform yet), then use the results as evidence of Java's poor performance.
The truly amusing part is that the Java community originally was populated and promoted by C/C++ programmers. Back in the early days of Java, we were so impressed with the platform that we switched over in spite of many of the performance issues of the time! Keep in mind that C programmers are always taught that performance is king. To make a switch like that meant that Java was a very compelling platform!
Most of the C/C++ programmers who didn't make the migration now talk about all the wonderful libraries they have that compare favorably to Java's APIs. Which is quite amusing given that Java's existence is what pushed these libraries into existence!
String x = ' Hello ' ; x = x + ' world '
because when executed its the same as:
String x = ' Hello ' ; x = x.clone().concat (' world ')
its slow, + operator returns new instance of String, old goes to garbage
collection. Now lets do it the clean proper Java way:
String x = ' Hello ' ; x.concat (' world ');
Just a minor correction.
String x = " Hello ";
x = x + " world ";
produces:
String x = " Hello ";
x = new StringBuffer(x).append(" world ").toString();
A more efficient way is:
StringBuffer buffer = new StringBuffer(" Hello ");
String x;
buffer.append(" world ");
x = buffer.toString();
Of course, in the case you listed, the performance difference is minor. It really only makes a difference when you're concatonating large strings, or performing parsing operations.
ouch, was this really necessary?
Given your apology, I do feel bad about my rather blunt manner. However, you do have to admit that you had it coming. In attempting to bait responders b
Actually, I did say that I wouldn't mind if Linux broke binary compatibility between major versions (i.e. 2.2 -> 2.4) However, it's obviously best if compatability is maintained.
To be perfectly clear, I'm not saying that Open Source drivers should go away. Many of them are very useful and should be preferred over any commercial driver. However, the number of devices for which Linux can never possibly keep up (scanners, cameras, MP3 players, NICs, 3D Accelerators, etc.) should be allowed to distribute binary drivers. That would make sure that you could at least get your hardware to work in the first place, rather than waiting a year or two for support.
*cough*Ahem*cough* And I quote from my original post:
Now if we had to switch drivers between major releases of the Linux kernel (e.g. 2.2 to 2.4), then there'd be no real issue.
But data rates on hard drives DO increase with more heads. This holographic storage is designed to act like multiple heads. Since the data is "stacked", you can read more on a single pass. My 11GB may not be correct, but neither is the assertion that the speed would be ~200MB/sec.
Well then, it's a good thing I'm running SunONE! Oh wait. No I'm not...
Well, here's one book I guarantee he didn't tie into his Foundation/Empire/Robot series. ;-)
I could just see wives everywhere using this as a way to make husbands put down their video game.
"Oh honey, look at the new cloths I got from Victoria Secret!"
*head whips around*
"I'm sorry! Did your plane crash?"
It's been out of print for a long time. They recently began printing it again. Thus, "lost masterpiece". :-)
Don't worry, you're the third person to ask that. Besides, it's good for the average Slashdotter to know that Asimov wrote something OTHER than the robot series.