SSID and WEP are completely independent. SSID does not raise the security level in any way, although it might look like it does.
As far as I can tell, SSID is just a convenience feature to keep different groups of users separate even if they happen to be on the same channels.
WEP is an encryption feature based on RC4, but it turns out the protocol is flawed- there are a couple of cracks out there that can crack it in under an hour.
In contrast VPN software can be arbitrarily secure; as the security is at a level above the wireless transport level, basically nobody can read the encrypted contents of the packets- VPN software is frequently across the internet for that reason.
Re:It was done with 1960s technology once...
on
China Plans Moonbase
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· Score: 3, Insightful
Technically it's an orbiter. Economically, it's a disaster.
Re:It was done with 1960s technology once...
on
China Plans Moonbase
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· Score: 4, Insightful
The Americans sent men to the moon using 1960s technology. The very thought of this makes my blood run cold. However, it worked.
I think you're seriously underestimating 1960s tech.
Actually, the Saturn V was better, cheaper (per lb of payload) and about as reliable as the Space Shuttle. The only big failure (ignoring Apollo I) was Apollo 13, and that wasn't a launch vehicle failure.
It also launched much more payload than the Space Shuttle can; the Space Shuttle simply can't reach the moon because of this.
If I suddenly magically increased c by 10%, that would be indisinguishable from stretching the universe by 10% in every spacial direction.
Oh well, that's OK then;-)
Um. Actually, you would effectively shrink the universe by 10%.
Seriously though- that would be very, very bad. Consider the moon in its orbit. It's sitting up there, and suddenly it's 10% closer. It's mass is the same and the mass of the earth is the same, but suddenly its 10% closer, and going 10% faster as well.
Basically, that would change its orbit, really noticeably, but that doesn't matter.
The earth would be a different distance from the Sun- that would have devastating effect on the biosphere. It would get really hot. But that doesn't matter either.
Far worse- all of the nuclear bonds holding the earth together would suddenly be 10% too short. The earth has been shrunk by 10%, and it doesn't like that. The earth would explode back out to its original size, overshoot, and finally relax to its original size; liberating immense energy. Everything on the earth would disintegrate. Without doing the maths a quadrillion on the Richter scale sounds about right. (Note that the Richter scale is a logarithmic scale.) That would matter.
Using your analogy, Columbus should never have gone so far out to America... It was extremely risky and had too many unknown quantities.
It's not the same; and I am comparing Antartica with Mars, not America. America was essentially habitable. A few indians, and you don't want to go too far north otherwise you freeze your manhood off, but it's habitable.
I consider Mars as a "backup" for civilization.
I consider space as a backup for civilisation. Mars is a subset of space.
I'm so sick of the whining about "oh, there's less atmosphere", "it's too cold", "it's too far", "we don't have the technology yet", "why do we have to go".
Oh well, in that case if you're sick of whining, then we obviously have to go right away.
I think we either go to Mars or stagnate and die.
Yeah, that's obviously going to happen. We go into space, we go to the moon, we go to Phobos and Deimos, and lots of other places, but the human race would be doomed if we never go to Mars. Uh huh.
In addition, most comets (not asteroids) are in hyperbolics or extremely eccentric orbits
True but irrelevant. We are only interested in the ones we can get to. There's thousands of NEAs; and I include Phobos and Deimos as NEAs, well half the time anyway;-)
OK, few points: there are advantages to going to a fixed planet rather than a stray comet or asteroid. First, it's easier - we have more data, more accuracy, and less chance for a course error.
I don't buy that argument; asteroids are easy to track to excellent accuracy, it's trivial astronomy; even amateurs do that routinely.
You're CRAZY if you think that you can't find a considerable amount of fuel on Mars as well.
There's no known energy source on Mars, apart from solar, and that's even weaker than on Earth. You could take a nuclear reactor with you, but there are issues with that too; noteably political.
Do the benefits outweigh the additional costs? Don't know.
"We need to mine something that isn't at the bottom of a gravity well."
As I recall from my physics courses, if it's something, by definition it's in the bottom of a gravity well.
Not really. With most asteroids and quite a few moons you are talking more like a gravity puddle at the very most. Phobos has an escape velocity which is about the speed a man can run.
And while we're on the subject of asteroid mining, sure they tend to have lots of heavy elements, but if you're looking for light stuff (say, oh, I dunno... reaction mass!?!), you need a heavy duty gravity well to hang on to it and collect it.
Comets and carbonaceous asteroids have plenty of ice. They aren't in any kind of heavy duty gravity well. Ice can be turned to steam for an ISP of 190 seconds, or electrolysed and burnt for an ISP of 455 seconds.
After expelling enough reaction mass to get to Mars in a reasonable amount of time... you honestly think bringing enough fuel to reach Martian escape velocity (remember, 1/3 G)
Surface gravity isn't it. Escape velocity of Mars is about 5km/s; that's only half that of Earth.
is really going to make that much of a difference?
Yes. It makes a big difference. ~6km/s is quite a considerable amount of fuel.
Heck, landing on Mars has the advantage over its satellites in that it at least has SOME atmosphere, so you don't need near as much shielding once you get there.
The Mars atmosphere provides only very modest shielding. On either Mars or an asteroid you will have to bury yourself underground to survive long term.
"If not now, when?
When the costs come down to nearer the costs that Dennis Tito can afford, then. If you think you can finance a trip before that- sure go ahead. Good luck.
We aren't at the point where Mars makes any kind of sense. It's a bit like Columbus discovered America and now we've been to American 6 times and everyone is saying- hey we've never been to Antartica! Antartica is the next step! It's the future of mankind!
Even that is pushing the analogy too far. Antartica is a lot more habitable than Mars. Mars has no atmosphere- well just 1% of earths- it's a vacuum; the lightbulbs in your house have more gas in them. Sure we can live on Antartica, or Mars, but we can't thrive there right now. We have the technology, but the economics aren't there- it's gonna cost hundreds of millions per person. That's no way colonise anywhere. It's pure flags and footprints. We go, we plant the flags, we come back. That's it. Yeah, it'd be glorious. But so what? It leads nowhere.
We need to mine something that isn't at the bottom of a gravity well. Mining something at the top means you can slide it downhill to LEO, or towards Mars. Until we have mining, Mars is out of reach for practical settlement; as is most of the solar system for that matter.
Phobos or Deimos- yes. The moon- maybe, a NEA or a comet, yes. Mars? Later.
If design patterns are used correctly, they accomplish one of 2 things, but rarely both:
* they speed up the development of a system
or
* they speed up the execution of a system
I don't really agree with this. In most systems I work on they do both- in different places. In one place speed isn't important (e.g. UI), in another it is (e.g. database lookups that are called from a zillion places).
It sounds to me like this guy has trouble picking the appropriate patterns from the start
No engineer always knows what pattern to use; for one thing the known requirements often change as you work towards delivery, and the patterns that best address these requirements often change with them.
I mean sure, a good pattern is along the lines of 'avoid having requirements that change', but that pattern is often inapplicable.
Seriously, as a consumer, I would have serious doubts about security, but I suppose I might just be underestimating the security of my current access.
Probably, as there's no security per se on the internet unless you encrypt.
Still security is still an issue- but not for you, for the ISP. They don't want somebody else leaching their bandwidth without paying.
The ultimate solution is VPN software- that way, gateway software permitting, they can put per-user bandwidth restrictions on you. Even if you gave away your password to someone else it wouldn't help as the ISP can just traffic shape you.
And it is better for you too. With VPN software it is encrypted across the WiFi network, so there's less chance of your neighbours hijacking your connections; atleast until it reaches your ISP anyway. (After that all bets are off).
The only downside of VPN software is there is often a slight performance penalty, latency and (sometimes) bandwidth; but it can still to be faster than ADSL.
You've missed it. Lots of people can't get 'standard last mile' because they are more than 3 miles away from exchange. I mean sure, if they can get ADSL they should.
Otherwise, ieee802.11b can give them connectivity- and may be able to give them faster throughput than ADSL can in fact.
Anyway, my experience doesn't align with yours. My ieee802.11b gives me much better link than I get from my ADSL line. Maybe you just have crappy equipment.
For all practical intents and purposes, it would. Consider the implications of trying to reuse C libraries that declare functions that take arguments of type int, or data structures that aggregate ints.
As you rightly point out, sometimes switch statements are useful-- another good reason to keep them in the language, huh ? (-;
Of course, I love switch statements, but the syntax is much more dangerous than it needs to be. If fact you don't actually need 'if' statements, just use switch;-)
So defining it for C++ would have made it incompatible? On reflection: No, I don't see that.
But that wasn't the point. My point was that many, many features of the language are unnecessarily dangerous; even an int; you haven't really grokked this point.
In that case I have no sympathy. If their product was so much use in Asia then they should have produced a plug-in. I mean it isn't like Asia isn't going to be a huge market or anything is it?;-)
You can't. That's what's so annoying. As a result of this decision, the entire internet has basically died; I won't even be able to get to google without RealNames to help me find it.
Good job I bookmarked slashdot really. What are we going to do? How can we survive this terrible decision by the software company of the beast?;-)
In that form, it is indeed a very weak and equivocal statement indeed, but judging by your snippage of my response, it's one that you're having a hard time supporting.
No, its very easy to support. You or I can write an entire book on the very obvious failings of C/C++ syntax. But, quite frankly I just can't be bothered here. You show no signs of being experienced enough with C++ and other languages to begin to appreciate it; plus in a few months all of these posting will be deleted. Only when you've learnt 20 or 30 computer languages and used atleast 10 in anger does it become clear just want went wrong- and what didn't (there's lots of good things about C/C++ too.)
Oh, ok, one more unbelieveably trivial example. Consider 'int'. What size is it? Yeah I know, its undefined 'for performance reasons'. WTF? What this really means is that a very significant fraction of programs are non portable; sure they might work, but as the size of the program grows, the probability approaches zero. If they had defined 'int' to be 32 bits, and created a different type, say 'nativeint', then only if you really need the performance would you use it. If you understand enough to know you want performance you use it. If you don't understand enough- I don't want people who don't understand what they are doing using 'int'. The standard language defaults are almost uniformly unnecessarily dangerous... and yes theres that equivocation again.
Yet, you didn't use STL, and were constantly forced to use unsafe pointer manipulations ?
Where did I say that?
But all this can be addressed by using object oriented code and STL.
Well, I certainly don't agree that switch statements disappear in sensibly written OO code, in fact absence of them is a sign of an inexperienced designer. Using polymorphism for that impacts both readability and speed, and implies a use of inheritance that is quite detrimental. Nearly all new OO designers misuse inheritance.
If you allocate memory ahead of time in C++, most of these "safety" issues that you complain about can also be avoided.
one gets the impression that you were never using C++ in the first place (compiling C with a C++ compiler doesn't count).
Gee do you think? Perhaps you'd do that. We didn't. We were/are actually using classes extensively, some people (I count myself in this, I have been OO'd for more than a decade) actually know how to write them. We didn't do any compiling C with the C++ compiler either; we had two compilers that interworked fine.
Java isn't used for the realtime stuff, because you can't implement real time software when you have non-deterministic garbage collection.
Actually, we aren't doing this, but IRC; garbage collection issues can be avoided in Java. If you allocate memory ahead of time you can avoid triggering the garbage collector entirely. We were actually having to do the same thing in C to avoid fragmentation. Most of our soft realtime has response times of upto 2 seconds. Hard realtime is down to about a millisecond and has deadlines you have to meet.
Anyway modern incremental garbage collectors run plenty fast enough for soft realtime...
Slashdot Mirror
SSID and WEP are completely independent. SSID does not raise the security level in any way, although it might look like it does.
As far as I can tell, SSID is just a convenience feature to keep different groups of users separate even if they happen to be on the same channels.
WEP is an encryption feature based on RC4, but it turns out the protocol is flawed- there are a couple of cracks out there that can crack it in under an hour.
In contrast VPN software can be arbitrarily secure; as the security is at a level above the wireless transport level, basically nobody can read the encrypted contents of the packets- VPN software is frequently across the internet for that reason.
Technically it's an orbiter. Economically, it's a disaster.
I think you're seriously underestimating 1960s tech.
Actually, the Saturn V was better, cheaper (per lb of payload) and about as reliable as the Space Shuttle. The only big failure (ignoring Apollo I) was Apollo 13, and that wasn't a launch vehicle failure.
It also launched much more payload than the Space Shuttle can; the Space Shuttle simply can't reach the moon because of this.
Oh well, that's OK then ;-)
Um. Actually, you would effectively shrink the universe by 10%.
Seriously though- that would be very, very bad. Consider the moon in its orbit. It's sitting up there, and suddenly it's 10% closer. It's mass is the same and the mass of the earth is the same, but suddenly its 10% closer, and going 10% faster as well.
Basically, that would change its orbit, really noticeably, but that doesn't matter.
The earth would be a different distance from the Sun- that would have devastating effect on the biosphere. It would get really hot. But that doesn't matter either.
Far worse- all of the nuclear bonds holding the earth together would suddenly be 10% too short. The earth has been shrunk by 10%, and it doesn't like that. The earth would explode back out to its original size, overshoot, and finally relax to its original size; liberating immense energy. Everything on the earth would disintegrate. Without doing the maths a quadrillion on the Richter scale sounds about right. (Note that the Richter scale is a logarithmic scale.) That would matter.
No. If you're not using VPN software you're incompetent. WEP is garbage, and SSID is sent in the clear.
You can sniff my packets all you like; you'll find they smell encrypted, I use VPN software...
I remember seeing people saying that when men landed on the moon. I'm still waiting for peace to break out.
It's not the same; and I am comparing Antartica with Mars, not America. America was essentially habitable. A few indians, and you don't want to go too far north otherwise you freeze your manhood off, but it's habitable.
I consider Mars as a "backup" for civilization.
I consider space as a backup for civilisation. Mars is a subset of space.
I'm so sick of the whining about "oh, there's less atmosphere", "it's too cold", "it's too far", "we don't have the technology yet", "why do we have to go".
Oh well, in that case if you're sick of whining, then we obviously have to go right away.
I think we either go to Mars or stagnate and die.
Yeah, that's obviously going to happen. We go into space, we go to the moon, we go to Phobos and Deimos, and lots of other places, but the human race would be doomed if we never go to Mars. Uh huh.
True but irrelevant. We are only interested in the ones we can get to. There's thousands of NEAs; and I include Phobos and Deimos as NEAs, well half the time anyway ;-)
OK, few points: there are advantages to going to a fixed planet rather than a stray comet or asteroid. First, it's easier - we have more data, more accuracy, and less chance for a course error.
I don't buy that argument; asteroids are easy to track to excellent accuracy, it's trivial astronomy; even amateurs do that routinely.
You're CRAZY if you think that you can't find a considerable amount of fuel on Mars as well.
There's no known energy source on Mars, apart from solar, and that's even weaker than on Earth. You could take a nuclear reactor with you, but there are issues with that too; noteably political.
Do the benefits outweigh the additional costs? Don't know.
That's the $100 billion question though isn't it?
As I recall from my physics courses, if it's something, by definition it's in the bottom of a gravity well.
Not really. With most asteroids and quite a few moons you are talking more like a gravity puddle at the very most. Phobos has an escape velocity which is about the speed a man can run.
And while we're on the subject of asteroid mining, sure they tend to have lots of heavy elements, but if you're looking for light stuff (say, oh, I dunno... reaction mass!?!), you need a heavy duty gravity well to hang on to it and collect it.
Comets and carbonaceous asteroids have plenty of ice. They aren't in any kind of heavy duty gravity well. Ice can be turned to steam for an ISP of 190 seconds, or electrolysed and burnt for an ISP of 455 seconds.
After expelling enough reaction mass to get to Mars in a reasonable amount of time ... you honestly think bringing enough fuel to reach Martian escape velocity (remember, 1/3 G)
Surface gravity isn't it. Escape velocity of Mars is about 5km/s; that's only half that of Earth.
is really going to make that much of a difference?
Yes. It makes a big difference. ~6km/s is quite a considerable amount of fuel.
Heck, landing on Mars has the advantage over its satellites in that it at least has SOME atmosphere, so you don't need near as much shielding once you get there.
The Mars atmosphere provides only very modest shielding. On either Mars or an asteroid you will have to bury yourself underground to survive long term.
"If not now, when?
When the costs come down to nearer the costs that Dennis Tito can afford, then. If you think you can finance a trip before that- sure go ahead. Good luck.
We aren't at the point where Mars makes any kind of sense. It's a bit like Columbus discovered America and now we've been to American 6 times and everyone is saying- hey we've never been to Antartica! Antartica is the next step! It's the future of mankind!
Even that is pushing the analogy too far. Antartica is a lot more habitable than Mars. Mars has no atmosphere- well just 1% of earths- it's a vacuum; the lightbulbs in your house have more gas in them. Sure we can live on Antartica, or Mars, but we can't thrive there right now. We have the technology, but the economics aren't there- it's gonna cost hundreds of millions per person. That's no way colonise anywhere. It's pure flags and footprints. We go, we plant the flags, we come back. That's it. Yeah, it'd be glorious. But so what? It leads nowhere.
We need to mine something that isn't at the bottom of a gravity well. Mining something at the top means you can slide it downhill to LEO, or towards Mars. Until we have mining, Mars is out of reach for practical settlement; as is most of the solar system for that matter.
Phobos or Deimos- yes. The moon- maybe, a NEA or a comet, yes. Mars? Later.
Altruism.
Actually you can download the updates manually if you wish; they're on their website somewhere or other. This is a supported patch technique.
I don't really agree with this. In most systems I work on they do both- in different places. In one place speed isn't important (e.g. UI), in another it is (e.g. database lookups that are called from a zillion places).
It sounds to me like this guy has trouble picking the appropriate patterns from the start
No engineer always knows what pattern to use; for one thing the known requirements often change as you work towards delivery, and the patterns that best address these requirements often change with them.
I mean sure, a good pattern is along the lines of 'avoid having requirements that change', but that pattern is often inapplicable.
Probably, as there's no security per se on the internet unless you encrypt.
Still security is still an issue- but not for you, for the ISP. They don't want somebody else leaching their bandwidth without paying.
The ultimate solution is VPN software- that way, gateway software permitting, they can put per-user bandwidth restrictions on you. Even if you gave away your password to someone else it wouldn't help as the ISP can just traffic shape you.
And it is better for you too. With VPN software it is encrypted across the WiFi network, so there's less chance of your neighbours hijacking your connections; atleast until it reaches your ISP anyway. (After that all bets are off).
The only downside of VPN software is there is often a slight performance penalty, latency and (sometimes) bandwidth; but it can still to be faster than ADSL.
Otherwise, ieee802.11b can give them connectivity- and may be able to give them faster throughput than ADSL can in fact.
Anyway, my experience doesn't align with yours. My ieee802.11b gives me much better link than I get from my ADSL line. Maybe you just have crappy equipment.
Hey- you're actually right for once!
Read up a few posts...
I never said that anywhere.
As you rightly point out, sometimes switch statements are useful-- another good reason to keep them in the language, huh ? (-;
Of course, I love switch statements, but the syntax is much more dangerous than it needs to be. If fact you don't actually need 'if' statements, just use switch ;-)
So defining it for C++ would have made it incompatible? On reflection: No, I don't see that.
But that wasn't the point. My point was that many, many features of the language are unnecessarily dangerous; even an int; you haven't really grokked this point.
In that case I have no sympathy. If their product was so much use in Asia then they should have produced a plug-in. I mean it isn't like Asia isn't going to be a huge market or anything is it? ;-)
Good job I bookmarked slashdot really. What are we going to do? How can we survive this terrible decision by the software company of the beast? ;-)
Sounds to me like you need one of those aluminum hats. You know; like the crazies wear. Otherwise, no comment ;-)
No, its very easy to support. You or I can write an entire book on the very obvious failings of C/C++ syntax. But, quite frankly I just can't be bothered here. You show no signs of being experienced enough with C++ and other languages to begin to appreciate it; plus in a few months all of these posting will be deleted. Only when you've learnt 20 or 30 computer languages and used atleast 10 in anger does it become clear just want went wrong- and what didn't (there's lots of good things about C/C++ too.)
Oh, ok, one more unbelieveably trivial example. Consider 'int'. What size is it? Yeah I know, its undefined 'for performance reasons'. WTF? What this really means is that a very significant fraction of programs are non portable; sure they might work, but as the size of the program grows, the probability approaches zero. If they had defined 'int' to be 32 bits, and created a different type, say 'nativeint', then only if you really need the performance would you use it. If you understand enough to know you want performance you use it. If you don't understand enough- I don't want people who don't understand what they are doing using 'int'. The standard language defaults are almost uniformly unnecessarily dangerous... and yes theres that equivocation again.
Where did I say that?
But all this can be addressed by using object oriented code and STL.
Well, I certainly don't agree that switch statements disappear in sensibly written OO code, in fact absence of them is a sign of an inexperienced designer. Using polymorphism for that impacts both readability and speed, and implies a use of inheritance that is quite detrimental. Nearly all new OO designers misuse inheritance.
If you allocate memory ahead of time in C++, most of these "safety" issues that you complain about can also be avoided.
What colour is the sky in your world?
Gee do you think? Perhaps you'd do that. We didn't. We were/are actually using classes extensively, some people (I count myself in this, I have been OO'd for more than a decade) actually know how to write them. We didn't do any compiling C with the C++ compiler either; we had two compilers that interworked fine.
Java isn't used for the realtime stuff, because you can't implement real time software when you have non-deterministic garbage collection.
Actually, we aren't doing this, but IRC; garbage collection issues can be avoided in Java. If you allocate memory ahead of time you can avoid triggering the garbage collector entirely. We were actually having to do the same thing in C to avoid fragmentation. Most of our soft realtime has response times of upto 2 seconds. Hard realtime is down to about a millisecond and has deadlines you have to meet.
Anyway modern incremental garbage collectors run plenty fast enough for soft realtime...