But what if we are not talking about coloring the surface of arbitrary 3-d shapes (I assume that is a manifold?), but rather 3-d _volumes_? I.e. Without any non-local tunneling?
Is there a minimum coverage needed for that case? Or am I too stupid to see that this is the same case as with manifolds?
I have a linksys ap+router (befw11s4 I think) and it works fine in wide-open mode, but not so well either in WEP or MAC-restricted mode -- often needing resets to let my two clients associate with it.
So it was cheap. I should have figured it was a piece of shit. (NB: it DOES work flawlessly in idiot mode tho, with the one restriction on requiring FTP downloads to be in PASV mode).
Question: is the netgear box any better? Any other recomendations?
I have the +802.11 version of this thing, and it does need a reset every so often to let my notebook associate with it (that's the 802.11 equivalent of getting an ethernet "link").
I've resisited upgrading the firmware as linksys (according to discussion sites) have bad software testing methodologies, and new firmware is more of a crapshoot than it has a right to be. Apparently my only-somewhat buggy firmware is a sweet spot, and several subsequent versions have been posted to the linksys website to only be quietly pulled a few days later.
In firmware even more than linux kernels, NEVER be the first kid on the block to get one.
1) contact with the tube will negate the lack of friction which makes the system workable -- so the emergency hatch would need to telescope to touch the ceiling. fine.
2) piercible? ok. Spelling aside, you can make the membrane out of whatever you desire, however, it still needs to hold against 1 atmosphere. It's very difficult to do that with somethat that is piercable AND durable enough to last a while.
3) So now you've pierced the wall --- you're in dirt. Great. That solved that problem real good!
yes. this IS a problem. However, it's a problem easily solved. Just equip each car with x hours of emergency air. As soon as something goes wrong, open the evacuated tunnel to the atmosphere. Choose x so that all the cars can withstand the induced wind thus induced.
So the camera is a trusted device. It embeds a secret digital key. When I take a picture proving the existence of little green men, the camera stores, in the watermark signal, a signed md5 sum of the reconstructed(*) image. (I'm assuming just one such signal, several signals tell you how the image has been altered, not just if)
Someone now questions whether this ufo pic I have is real: all I have to do is calculate the md5sum of the image, get the public half of my camera's key (printed on the bottom?) and verify that this indeed matches the signed image key.
Kinda neat.
(*) However, I'm curious. The embedded signal needs to contain the bits it replaces AND some payload data. How can this be a lossless embedding? Did these guys go and invent a recursivly applicable lossless compressor? So I suspect it is not lossless, but merely a lot better than other schemes.
so can anyone figure out how to lay out the dots, so that each OVERLAPPING area of dots is unique?
I can figure out a backtracking solution to the 1-D case, but that would seem to run in n**2 time. Now I REALLY doubt that they've used an n**2 algorithm for n~= 2**64 (I estimate you'll need 64 bits to get the required accuracy).
Basically, the 1-D case is: create a sequence of bits so that no substring of length m (chosen a-priori, in our case 64) occurs twice.
To make things simpler: we can increase m, and accept a less optimal solution (optimality is how many unique sequences occur)
To make things harder: 1) we want to be able to quickly map the unique number to the offset, and 2) we want a hierarchial solution (so that we don't have to layout the whole sequence at once-- they don't have enough storage to store the whole sequence). This point interacts well with choosing a larger m.
It shouldn't be too hard (or large) to get signed md5 sums of each file from some reputable source. For all I know, already availible, but I've not seen it at the granularity of single files.
Can sny rocket scientists out there explain how two bodies in the same orbit can have different velocities, AND how the relative velocities can change over time?
They claim that for 90 odd years, the asteroid will accellerate ahead of us, to catch up with earth from behind, at which point it will fall back and we'll cath up with it. And then it repeats.
weird! I can't figure out how this is comes about, and the article didn't think it worth mentioning.
Sorry to yell and all, but c'mon, what sort of geeks are you?
The Four color conjecture is interesting because its confirmation was the first computer assisted proof.
It was proven manually that all maps are reducible to 1500 odd cases. These were then exhaustively tested over 1000 odd computer hours to verify that indeed they could all be colored using no more than four colors.
> Wonder if Bill W had any say in that sort of usage of a pic of Calvin
C&W were _never_ licenced for any merchanise. Anytime you see a calvin T-Shirt (*sniff* I still have mine) or sticker, it's a copyright infringement. BW resisted the truckloads of money this would bring in, as it would compromise the magical world that Calvin lives in.
BW is an artist of great integrity, and suspect his reclusiveness after the end of C&H (I mean, it's been how many years?) is mostly due to disgust with the publishing industry. But this is pure speculation on my part.
As for the pissing calvin stickers, I assume that the picture of a spiky-haired boy is generic enough to not warrant action by the publishers, or else that action is unlike the "real" calvin enough to be protected as satirical use of calvin's reputation.
Given the speed of processors, how likely is a line in the cache to survive a context switch, even if it weren't flushed explicitly? I would imagine fairly small. (I'm punting on which L cache I mean: too lazy to think hard about it.)
However, I've always wondered if there was a performance win to multiple threads running in the same memory space as compared to multiple processes, for this very reason.
Anecdotally no: I spoke to the BeOS guys at a conference back in the days of wanting every cycle you could get, and they didn't give threads from the same process as the previous thread any higher probability of running next, which would be the natural thing to do if it were a performance win.
I'm smiling because that was the method of security that M$ use(s/d?) for activeX controls. Widely derided as unworkable, and prone to misuse (IIRC, someone got hold of a M$ private key, and they had to revoke it.)
actually, 500MB removable and cheap storage would be great.
mp3 players, digital cameras, digital books... all of these want small, cheap, media in the 500MB range.
It just wouldn't fly for prerecorded music. (And not only because of their crappy DRM scheme) Music media is dead. I predict that CDs will be the last major music media. SACD and DVD-Audio may have a breif blossom, but for the most part, the current generation of adults are happy with CDs, and the current adolescent generation will wonder why people care about the physical media when you transfer files from your mp3 server to your ipod.
Unfortunately, prerecorded music was exactly the niche Dataplay aimed at.
I was going to say that this would be a perfect match for the 10MP cameras coming out, but I expect those to eat batteries nearly as fast as they eat RAM so they'll be be used mostly in a tethered environment.
I tried to, but couldn't, justify the zipcar argument. (I'm in the s/e as well, btw)
For w/e trips, a rental is cheaper, and for infrequent short trips, such as shopping, a cab is cheaper. That's all I need a car for, pretty much. Ok, so I can't impress dates with my car, but zipcar would hardly help there either.
The only niche for a zipcar would be if I often had a day's worth of errands, as pretty much the only arguments are convenience of pickup, and letting you run around town on your own.
I was toying with rolling something like this for myself and friends: pool a bit of money, buy a cheap car, insure it to the wazoo. Since I need a car less that 10% of the time, almost 10 people could share the car. Resident parking the SE isn't that bad. I figured it should be easy to get access to a decent car for a bit under $100 a month. In the end, that failed the cab/rental acid test as well: $100 is quite a bit of cabbage and rentals; more than I spend at any rate.
Do rental agencies deliver? That would make zipcar even less attractive.
You have a couple of options. First of all, you can recover quite a bit of energy from the work performed by pressure: These devices all have sealed bladders that provide most of the bouyancy on the upslope.
However, when compressed, they will get hot, and this heat can be used to drive a sterling engine against the temperature sink of the ocean. Likewise, on rising, the bladders will cool, allowing you to drive the sterling engine in reverse, with the bladder as the sink and the ocean as a heat source.
To provide the necessary extra bouyancy to go from dive to rise, a chemical could be released into a reservoir of seawater (off hand I can't think of such a chemical: you need something which expands the volume of seawater). However, you could likely carry enough of such a chemical for many dives. To go from rise to sink, you need merely vent the cavern, fill it with sea-water, and start over again.
Ah the solution is that the blinkes aren't total activity on the subnet, but rather ACK packets coming into the hub. So the reason the link to the main computer is blinking like mad and the mp3 player isn't is that the main computer is acking, while the mp3 isn't.
I dunno. I have a netgear dual speed hub (according to its faceplate: the DS104, if you must know) that does exactly what you claim a switch does. I must admit that I'm a bit hazy on the details as to how it goes about mapping MAC addresses to IP addresses (I just plug things in), but according to the little blinkies, when I'm downloading mp3s to the 100bT file server, the 10bT i-opener isn't getting any packets. Likewise, when I nfs read aforementioned mp3s from the i-opener, none of those packets make it to the AP, which is also connected to the hub.
So the hub clearly directs traffic, and also lets pairs of ports of the hub talk at their highest common speed.
I think you got your defns bassackwards. Could be that the market for switches has disapeared, and hubs are now cheap enough to fill that space too. However, I think your defn of a hub sounds like a bridge, but networking class was many years ago, and I'm not willing to assert that statement as a fact.
Slashdot Mirror
Fantastic!
Great visualisation.
But what if we are not talking about coloring the surface of arbitrary 3-d shapes (I assume that is a manifold?), but rather 3-d _volumes_? I.e. Without any non-local tunneling?
Is there a minimum coverage needed for that case? Or am I too stupid to see that this is the same case as with manifolds?
thanks for the link and info.
yess.
I have a linksys ap+router (befw11s4 I think) and it works fine in wide-open mode, but not so well either in WEP or MAC-restricted mode -- often needing resets to let my two clients associate with it.
So it was cheap. I should have figured it was a piece of shit. (NB: it DOES work flawlessly in idiot mode tho, with the one restriction on requiring FTP downloads to be in PASV mode).
Question: is the netgear box any better? Any other recomendations?
I have the +802.11 version of this thing, and it does need a reset every so often to let my notebook associate with it (that's the 802.11 equivalent of getting an ethernet "link").
I've resisited upgrading the firmware as linksys (according to discussion sites) have bad software testing methodologies, and new firmware is more of a crapshoot than it has a right to be. Apparently my only-somewhat buggy firmware is a sweet spot, and several subsequent versions have been posted to the linksys website to only be quietly pulled a few days later.
In firmware even more than linux kernels, NEVER be the first kid on the block to get one.
YMMV of course.
yet these guys have a patent on exactly that.
Strange that the patent examiners would be unaware of at least 30 years of open speculation.
If I didn't accept their competence as an absolute, I'd start wondering about the credibility of the patent office.
where do I start?
1) contact with the tube will negate the lack of friction which makes the system workable -- so the emergency hatch would need to telescope to touch the ceiling. fine.
2) piercible? ok. Spelling aside, you can make the membrane out of whatever you desire, however, it still needs to hold against 1 atmosphere. It's very difficult to do that with somethat that is piercable AND durable enough to last a while.
3) So now you've pierced the wall --- you're in dirt. Great. That solved that problem real good!
yes. this IS a problem. However, it's a problem easily solved. Just equip each car with x hours of emergency air. As soon as something goes wrong, open the evacuated tunnel to the atmosphere. Choose x so that all the cars can withstand the induced wind thus induced.
and how much have _you_ given? Who cares if it's small in relative numbers, it's the absolute values that matter.
Oh... I get it, I think.
So the camera is a trusted device. It embeds a secret digital key. When I take a picture proving the existence of little green men, the camera stores, in the watermark signal, a signed md5 sum of the reconstructed(*) image. (I'm assuming just one such signal, several signals tell you how the image has been altered, not just if)
Someone now questions whether this ufo pic I have is real: all I have to do is calculate the md5sum of the image, get the public half of my camera's key (printed on the bottom?) and verify that this indeed matches the signed image key.
Kinda neat.
(*) However, I'm curious. The embedded signal needs to contain the bits it replaces AND some payload data. How can this be a lossless embedding? Did these guys go and invent a recursivly applicable lossless compressor? So I suspect it is not lossless, but merely a lot better than other schemes.
so can anyone figure out how to lay out the dots, so that each OVERLAPPING area of dots is unique?
I can figure out a backtracking solution to the 1-D case, but that would seem to run in n**2 time. Now I REALLY doubt that they've used an n**2 algorithm for n~= 2**64 (I estimate you'll need 64 bits to get the required accuracy).
Basically, the 1-D case is: create a sequence of bits so that no substring of length m (chosen a-priori, in our case 64) occurs twice.
To make things simpler: we can increase m, and accept a less optimal solution (optimality is how many unique sequences occur)
To make things harder: 1) we want to be able to quickly map the unique number to the offset, and 2) we want a hierarchial solution (so that we don't have to layout the whole sequence at once-- they don't have enough storage to store the whole sequence). This point interacts well with choosing a larger m.
It shouldn't be too hard (or large) to get signed md5 sums of each file from some reputable source. For all I know, already availible, but I've not seen it at the granularity of single files.
Can sny rocket scientists out there explain how two bodies in the same orbit can have different velocities, AND how the relative velocities can change over time?
They claim that for 90 odd years, the asteroid will accellerate ahead of us, to catch up with earth from behind, at which point it will fall back and we'll cath up with it. And then it repeats.
weird! I can't figure out how this is comes about, and the article didn't think it worth mentioning.
Sorry to yell and all, but c'mon, what sort of geeks are you?
The Four color conjecture is interesting because its confirmation was the first computer assisted proof.
It was proven manually that all maps are reducible to 1500 odd cases. These were then exhaustively tested over 1000 odd computer hours to verify that indeed they could all be colored using no more than four colors.
> Wonder if Bill W had any say in that sort of usage of a pic of Calvin
C&W were _never_ licenced for any merchanise. Anytime you see a calvin T-Shirt (*sniff* I still have mine) or sticker, it's a copyright infringement. BW resisted the truckloads of money this would bring in, as it would compromise the magical world that Calvin lives in.
BW is an artist of great integrity, and suspect his reclusiveness after the end of C&H (I mean, it's been how many years?) is mostly due to disgust with the publishing industry. But this is pure speculation on my part.
As for the pissing calvin stickers, I assume that the picture of a spiky-haired boy is generic enough to not warrant action by the publishers, or else that action is unlike the "real" calvin enough to be protected as satirical use of calvin's reputation.
yeah, it's only 1.5 orders of prefix magnitude away from visible light. red light is about 450 THz.
I think this explains why it is kinda directional, if I remember my phys101 correctly.
Given the speed of processors, how likely is a line in the cache to survive a context switch, even if it weren't flushed explicitly? I would imagine fairly small. (I'm punting on which L cache I mean: too lazy to think hard about it.)
However, I've always wondered if there was a performance win to multiple threads running in the same memory space as compared to multiple processes, for this very reason.
Anecdotally no: I spoke to the BeOS guys at a conference back in the days of wanting every cycle you could get, and they didn't give threads from the same process as the previous thread any higher probability of running next, which would be the natural thing to do if it were a performance win.
heh.
I'm smiling because that was the method of security that M$ use(s/d?) for activeX controls. Widely derided as unworkable, and prone to misuse (IIRC, someone got hold of a M$ private key, and they had to revoke it.)
le plus ca change...
actually, 500MB removable and cheap storage would be great.
mp3 players, digital cameras, digital books... all of these want small, cheap, media in the 500MB range.
It just wouldn't fly for prerecorded music. (And not only because of their crappy DRM scheme) Music media is dead. I predict that CDs will be the last major music media. SACD and DVD-Audio may have a breif blossom, but for the most part, the current generation of adults are happy with CDs, and the current adolescent generation will wonder why people care about the physical media when you transfer files from your mp3 server to your ipod.
Unfortunately, prerecorded music was exactly the niche Dataplay aimed at.
I was going to say that this would be a perfect match for the 10MP cameras coming out, but I expect those to eat batteries nearly as fast as they eat RAM so they'll be be used mostly in a tethered environment.
I tried to, but couldn't, justify the zipcar argument. (I'm in the s/e as well, btw)
For w/e trips, a rental is cheaper, and for infrequent short trips, such as shopping, a cab is cheaper. That's all I need a car for, pretty much. Ok, so I can't impress dates with my car, but zipcar would hardly help there either.
The only niche for a zipcar would be if I often had a day's worth of errands, as pretty much the only arguments are convenience of pickup, and letting you run around town on your own.
I was toying with rolling something like this for myself and friends: pool a bit of money, buy a cheap car, insure it to the wazoo. Since I need a car less that 10% of the time, almost 10 people could share the car. Resident parking the SE isn't that bad. I figured it should be easy to get access to a decent car for a bit under $100 a month. In the end, that failed the cab/rental acid test as well: $100 is quite a bit of cabbage and rentals; more than I spend at any rate.
Do rental agencies deliver? That would make zipcar even less attractive.
well, not to be reasonable or anything, but m$ IS a software company, not a hardware company, so they WOULD show both macs and PCs.
Kinda like the blues brothers (well, not really, but I like the quote): "we have both kinds [of music]: Country AND Western!"
man! they pissed on your rug? Shit. And that really pulled the room together, ya know?
I know what you mean, but eventually, people DID get fired for buying IBM. IIRC, it was compaq that finally falsified that truism.
I'm lazy: can anyone figure out for me whether I can play warcraft 3 w/o rebooting?
Also, where can I buy wc3 on the cheap?
Can anyone recommend a side-scroller that runs under linux?
You have a couple of options. First of all, you can recover quite a bit of energy from the work performed by pressure: These devices all have sealed bladders that provide most of the bouyancy on the upslope.
However, when compressed, they will get hot, and this heat can be used to drive a sterling engine against the temperature sink of the ocean. Likewise, on rising, the bladders will cool, allowing you to drive the sterling engine in reverse, with the bladder as the sink and the ocean as a heat source.
To provide the necessary extra bouyancy to go from dive to rise, a chemical could be released into a reservoir of seawater (off hand I can't think of such a chemical: you need something which expands the volume of seawater). However, you could likely carry enough of such a chemical for many dives. To go from rise to sink, you need merely vent the cavern, fill it with sea-water, and start over again.
Ah the solution is that the blinkes aren't total activity on the subnet, but rather ACK packets coming into the hub. So the reason the link to the main computer is blinking like mad and the mp3 player isn't is that the main computer is acking, while the mp3 isn't.
I dunno. I have a netgear dual speed hub (according to its faceplate: the DS104, if you must know) that does exactly what you claim a switch does. I must admit that I'm a bit hazy on the details as to how it goes about mapping MAC addresses to IP addresses (I just plug things in), but according to the little blinkies, when I'm downloading mp3s to the 100bT file server, the 10bT i-opener isn't getting any packets. Likewise, when I nfs read aforementioned mp3s from the i-opener, none of those packets make it to the AP, which is also connected to the hub.
So the hub clearly directs traffic, and also lets pairs of ports of the hub talk at their highest common speed.
I think you got your defns bassackwards. Could be that the market for switches has disapeared, and hubs are now cheap enough to fill that space too. However, I think your defn of a hub sounds like a bridge, but networking class was many years ago, and I'm not willing to assert that statement as a fact.