Apple's Education customers probably had some small part in this, too -- I screamed at Apple pretty loud saying we weren't ready, and they replied that we should buy our next year's machines by January.
Never mind that our next budget year isn't 'til June.
I think this will allow schools to make one more year's worth of purchases that are still OS 9 compatible.
One more year of OS X's maturation (both client AND server) will really really help schools make the transition.
(Not to mention we have to save our pennies and budget for new versions of Office, PhotoShop, etc., since we don't want to buy more RAM to run X just to use all classic apps...)
I'm still having bad dreams about how we're going to train everyone to use OS X, or how a mixed 9 and X environment will work.
(I don't care how flawed it was, people will MISS that darn old Chooser)
According to this site, the "velocity of propagation" of signals in the blue pair in CAT5 cable is 66% that of "c", the true speed of light. (A few percent of that is because of the twists -- if you completely straightened out the individual wires, they'd stretch longer than the original length of the cable)
Of course there's the difference between the speed of one electron vs. the speed that voltage changes (i.e. information) travel along the wire.
According to this guy, the actual movement of electrons is VERY very slow through a normal wire, on the order of centimeters per hour.
What about superconductors?
I didn't have tons of luck Googling, but I found a message board posting that states that the electron drift rate is much higher in superconductors.
And then there's this physics Q&A about why electrons don't travel at actually the speed of light.
Right. Okay. Go read the article! (This is the correct response to 90% of the posts in this thread)
18K is relatively warm compared to plain-old superconducting metals. When superconductivity was discovered in 1911 occurring in Mercury, later in other metals as well, it was at only a few degrees Kelvin. 18K is relatively warm compared to that.
Half a century later, in 1986, we found ceramic compounds that would superconduct at much much higher temperatures. Those compounds superconduct by a different process, so they're dubbed Type 2 superconductors. (as opposed to Type 1 for metalic elements)
The article doesn't say -- or they probably don't even know for sure -- what type of superconductivity was observed in Plutonium. Or if they were using pure elemental Plutonium or some compound that contained it.
And finally, lots of other comments here make fun of how "useful" Plutonium is. Duh. It's not:
The discovery has no immediate practical value but is important because it adds a new dimension to the study of superconductivity, Stewart said.
"You can't make practical materials out of something as radioactive and chemically poisonous as plutonium," he said, "but John Sarrao and this collaborative team have made a big leap in understanding superconductivity from a fundamental point of view."
Basically, it means that superconductivity is still not completely understood -- this uncovers yet another twist, and will help to develop the theories further.
Some workstations turn up their ethernet link by software, and then try to use the port right away to, for instance, obtain a DHCP lease.
Spanning tree starts doing its work as soon as it sees ethernet link. So, there's a delay between the time the link comes up and when traffic starts to pass.
Apple's DHCP implementation was bitten by this on some of their machines, affecting the startup of the Appletalk stack, which unlike DHCP, will not retry its initial auto-configuration and address discovery.
I've always been skeptical of "intelligence" added to layers below 3. There are always unforseen interactions and consequences to ANY variance from a set standard.
Anyone who actually reads/. immediately recognizes these duplicate postings.
Wouldn't the editors of/. be expected to READ it as well?
Why weren't there so many duplicates three years ago? What's changed?
Okay, griping done -- now, what is a constructive way of dealing with this?
How about a policy: Post more than three duplicates (previous story 1 year old) and you lose your story-posting priveleges? And CowboyNeal will beat you silly with a nerfbat.
It's getting downright silly.
How about the ability for moderators to mark a story redundant? Give the story itself a Karma of, say, 1000, so it would take a lot of such moderations. Keep the Karma hidden, to help prevent abuse.:(
I'm surprised nobody else mentioned that the Achilles' Heel of CDs are their TOP side, not the bottom.
CDs have all the data pressed or burned on a very thin layer just beneath the surface of the TOP side of the disc. Scratch that layer, you're actually scraping bytes right off the disc, permanently.
Scratches on the bottom side of the disc, a layer that includes almost the entire thickness of the disc, are minor by comparison.
DVDs are much easier to fix by polishing, because the data layer is in the exact middle of the disc -- indeed even "single-sided" DVDs are two half-thickness discs glued together. Thus the data layer is shielded from both directions, and it's much harder to permanently zarch a DVD.
There's something missing here, since viruses can't eat!
Could it possibly have been a competeing strain of bacteria which eat meat and harmful bacteria, yet don't bother humans?
It's important to remember that viruses are creepy, dead bits of genetic code. They are not cells, they have no life processes of their own. They barely have moving parts. Think of them as evil "keys" that float around and perfectly fit through the "keyholes" in susceptible cells. Once they fit in the cell's lock, the cell does all the work of opening up the virus capsule, extracting and incorporating its RNA, and then manufacturing more viruses according to that RNA.
I really wish Slashdot's editors would READ SLASHDOT!
I can understand reposts that are a couple weeks apart.
But these few-days-apart repostings are increasingly common, and it's getting really irritating. Back in the days of five-digit usernumbers, this almost NEVER happened.
Can't the editors of Slashdot be expected to have read all the Slashdot stories for at least the past week, so as to recognize obvious duplicates? I think it would be reasonable to expect them to search for duplicates for the past year, but that's just me.
How long before moderators can act on the stories themselves? Add a "-5 Repost" option...:)
It is a phase-change technology -- instead of "burning" a dye layer as in CD-R, CD-RW melts a layer of metalic material.
If a spot of this material is heated above its melting point, and then allowed to cool very quickly, i.e. turn the laser on full and then turn it completely off, it solidifies in a kind of cloudy manner, refered to as the amorphous state. This happens because while melted, the various molecules float around in a random orientation. When cooled quickly, they are "frozen" in this random state. This makes that spot cloudy enough so that light isn't reflected clearly by the reflective layer below.
On the other hand, if you heat that same spot again to its melting point (full-power laser) but then let it cool slowly using a lower-power laser to keep it slightly heated, the moluecules have time to crystalize, lining up with each other to form a nice, clear crystal. When the laser finally turns all the way off, that spot is now frozen in this transparent state, no longer cloudy, so that light passes through and reflects brightly off the mirrored surface below.
The downsides are: The contrast between the cloudy==unreflective and clear==reflective states is not as great as a pressed CD or opaque-dye CD-R, so it takes a more sensitive reader. I believe that CD-RW capable readers specifically recognize that it's a CD-RW, and use different thresholds of brightness for determining 1s and 0s. That's why older players aren't compatible.
The other one is that this melting/solidifying process gradually damages the crystaline layer. After enough "meltings", it wears out and gets permanently cloudy.
Right... and currently the Earth's magnetic north pole is near our geographic south pole.
Doesn't stay there for long, in geologic time frames, however. Our magnetic pole changes fairly regularly, according to geologists who care about such things.:)
No, I need to find a naturally occuring dipole that an Alien would be likely to find in another galaxy. One whose polarity I could describe unambiguously.
Of course, if one stands in the northern hemisphere, looking at the sun, the definition of "left" and "right" is one way.
Move to the southern hemisphere. You're now the other-side-up, and left and right are reversed.
This is now wandering off-topic even further, but: Have you every tried to define "left"? Pretend you're on the phone with aliens, who want to know what we define as "left".
Up, down are easy -- gravity based definitions are fine. But then try to describe clockwise, or right.
I come close when I have the alien move an electron in the "up" direction, and then try to define clockwise in terms of the direction of the magnetic field lines created.
But then you need a way to define the polarity of the magnetic field -- and I can't think of a naturally occuring magnetic dipole to compare it to.
Nasty brain twister, if you let yourself be kept up at night thinking about such things.:)
An amateur station transmitting signals to control a model craft may be operated as follows:
(a) The station identification procedure is not required for transmissions directed only to the model craft, provided that a label indicating the station call sign and the station licensee's name and address is affixed to the station transmitter.
(b) The control signals are not considered codes or ciphers intended to obscure the meaning of the communication.
(c) The transmitter power must not exceed 1 W.
Still, 1000mW is a lot more than the unlicensed transmitters use.:)
With Apple's "Airport" implementation, there seems to be a 200-300ms loss of connectivity -- if I'm using "ping -f" over the link I lose about 40-60 packets.
Carrying on a tcp transfer, there's at most a brief pause as a couple packets are retransmitted. Sometimes I don't notice a hiccup at all.
This is without any WEP turned on.... it might add some extra time.
A number of assumptions are at play: The access points you're crossing among are all on the same LAN segment, they all have the same "name"/SSID, and your network switches can handle the idea of an MAC address that was coming from one port suddenly coming from another -- most switches work fine. (Hubs wouldn't be an issue, obviously)
At least the way Apple implemented their clients, nothing in such a switch between same-SSID WAPs triggers interface up/down -- there's no DHCP request, everything stays the same.
Makes me wonder how the software posted about here deals with transitions between "cells" of a meshed network.
Or was that a special article that only I could see?:)
On the other hand, I'm really curious why Tuesday's article now has only 28 comments, while this current one, three days later, has well over a hundred. Both were in the Science section of slashdot... what am I missing?
- Peter
More information about the anti-matter?
on
A Shocking Space Movie
·
· Score: 3, Interesting
So in typical Slashdot fashion, they talk about the stream of anti-matter.
It's only mentioned briefly in the actual article as well:
"The jet looks like steam from a high-pressure boiler," said David Burrows of Penn State, another coauthor of the paper, "except when you realize you are looking at a stream of matter and anti-matter electrons moving at half the speed of light!"
So how do they know that one of these streams is made up of anti-electrons?
Ira Flatow is having a conversation about anti-matter on Science Friday as I'm typing this. It's a fascinating topic, so I always hate to see it just glossed over in press releases like this.
At 44GB per tape and 28.2Mbps data rate, these decks will make nice backup drives.
The decks have IEEE1394(Firewire) interfaces, and have a raw-data mode typically used for recording encrypted data from satellite broadcasts, so it will be trivial to write drivers to allow data storage and retrieval.
Now, I said "cheap" in the subject -- $1000 is already not bad for a 44GB media size, but if D-VHS takes off in the consumer market the prices will plummet!
The concept here is that all ER technicians will have the simple scanning device that will pull important medical data off the chip.
If you're unconscious, and the ER tech can just scan off you that you're diabetic and allergic to penicillin, that's a Good Thing.
Of course, conspiracy theorists say that every time you have surgery, the Government is implanting these in us without our knolwedge, and using it to track us. Oooooh!
Toward the end of the article they talk about the Pen's ability to use any surface.
In reality, it's an optical mouse head on the tip of a pen. It's not your typical pen-based input device.
Granted, this has some cool applications, but makes it very un-pen-like for cursor movement -- you'd be drawing on whatever surface just like you'd be moving a mouse, with no absolute positional control, just delta.
And all this has NOTHING to do with replacing a keyboard. Why did the article keep bringing that up? They didn't mention handwriting recognition at all, which would be the essential component.
Not to mention that keyboards would still be needed for high-speed data entry.
Has someone named this syndrome? The "Wow, this new technology will replace all the current technology, look, isn't it cool?"-syndrome that the mass news media falls into all the time.
To store the energy a mixture of methanol and water is employed...
Pure methanol is not needed. It's possible that the ratio of methanol to water can be adjusted to ensure fire safety while still providing enough useful energy for these devices to be successful.
- Peter
Slashdot Mirror
Apple's Education customers probably had some small part in this, too -- I screamed at Apple pretty loud saying we weren't ready, and they replied that we should buy our next year's machines by January.
Never mind that our next budget year isn't 'til June.
I think this will allow schools to make one more year's worth of purchases that are still OS 9 compatible.
One more year of OS X's maturation (both client AND server) will really really help schools make the transition.
(Not to mention we have to save our pennies and budget for new versions of Office, PhotoShop, etc., since we don't want to buy more RAM to run X just to use all classic apps...)
I'm still having bad dreams about how we're going to train everyone to use OS X, or how a mixed 9 and X environment will work.
(I don't care how flawed it was, people will MISS that darn old Chooser)
- Peter
According to this site, the "velocity of propagation" of signals in the blue pair in CAT5 cable is 66% that of "c", the true speed of light. (A few percent of that is because of the twists -- if you completely straightened out the individual wires, they'd stretch longer than the original length of the cable)
Of course there's the difference between the speed of one electron vs. the speed that voltage changes (i.e. information) travel along the wire.
According to this guy, the actual movement of electrons is VERY very slow through a normal wire, on the order of centimeters per hour.
What about superconductors?
I didn't have tons of luck Googling, but I found a message board posting that states that the electron drift rate is much higher in superconductors.
And then there's this physics Q&A about why electrons don't travel at actually the speed of light.
- Peter
18K is relatively warm compared to plain-old superconducting metals. When superconductivity was discovered in 1911 occurring in Mercury, later in other metals as well, it was at only a few degrees Kelvin. 18K is relatively warm compared to that.
Half a century later, in 1986, we found ceramic compounds that would superconduct at much much higher temperatures. Those compounds superconduct by a different process, so they're dubbed Type 2 superconductors. (as opposed to Type 1 for metalic elements)
The article doesn't say -- or they probably don't even know for sure -- what type of superconductivity was observed in Plutonium. Or if they were using pure elemental Plutonium or some compound that contained it.
And finally, lots of other comments here make fun of how "useful" Plutonium is. Duh. It's not:
Basically, it means that superconductivity is still not completely understood -- this uncovers yet another twist, and will help to develop the theories further.
Secrets of the universe stuff, you know.
- Peter
Good GOD! EDITORS! WAKE UP!
/. care about all these duplicates?
Why don't the higher-ups at
- Peter
Well, mostly transparent to end stations.
Some workstations turn up their ethernet link by software, and then try to use the port right away to, for instance, obtain a DHCP lease.
Spanning tree starts doing its work as soon as it sees ethernet link. So, there's a delay between the time the link comes up and when traffic starts to pass.
Apple's DHCP implementation was bitten by this on some of their machines, affecting the startup of the Appletalk stack, which unlike DHCP, will not retry its initial auto-configuration and address discovery.
I've always been skeptical of "intelligence" added to layers below 3. There are always unforseen interactions and consequences to ANY variance from a set standard.
- Peter
Anyone who actually reads /. immediately recognizes these duplicate postings.
/. be expected to READ it as well?
:(
Wouldn't the editors of
Why weren't there so many duplicates three years ago? What's changed?
Okay, griping done -- now, what is a constructive way of dealing with this?
How about a policy: Post more than three duplicates (previous story 1 year old) and you lose your story-posting priveleges? And CowboyNeal will beat you silly with a nerfbat.
It's getting downright silly.
How about the ability for moderators to mark a story redundant? Give the story itself a Karma of, say, 1000, so it would take a lot of such moderations. Keep the Karma hidden, to help prevent abuse.
- Peter
No no no! CD players are designed to focus though 1.2mm of plastic to the surface very very near the "top" side of the CD. See a diagram of CD layers.
It's DVDs that have the same thickness of plastic on both sides, as my original post said.
It is true, though, that some CD-R manufacturers paint on a stronger anti-scratch coating, making it harder to scratch off the reflective coating.
I'm surprised nobody else mentioned that the Achilles' Heel of CDs are their TOP side, not the bottom.
CDs have all the data pressed or burned on a very thin layer just beneath the surface of the TOP side of the disc. Scratch that layer, you're actually scraping bytes right off the disc, permanently.
Scratches on the bottom side of the disc, a layer that includes almost the entire thickness of the disc, are minor by comparison.
DVDs are much easier to fix by polishing, because the data layer is in the exact middle of the disc -- indeed even "single-sided" DVDs are two half-thickness discs glued together. Thus the data layer is shielded from both directions, and it's much harder to permanently zarch a DVD.
- Peter
There's something missing here, since viruses can't eat!
Could it possibly have been a competeing strain of bacteria which eat meat and harmful bacteria, yet don't bother humans?
It's important to remember that viruses are creepy, dead bits of genetic code. They are not cells, they have no life processes of their own. They barely have moving parts. Think of them as evil "keys" that float around and perfectly fit through the "keyholes" in susceptible cells. Once they fit in the cell's lock, the cell does all the work of opening up the virus capsule, extracting and incorporating its RNA, and then manufacturing more viruses according to that RNA.
- Peter
I've always thought they should better advertize the real pronunciation of Uranus. Why not spell it "urinous"?
:)
At least I find the yellow stuff less offensive...
- Peter
I really wish Slashdot's editors would READ SLASHDOT!
:)
I can understand reposts that are a couple weeks apart.
But these few-days-apart repostings are increasingly common, and it's getting really irritating. Back in the days of five-digit usernumbers, this almost NEVER happened.
Can't the editors of Slashdot be expected to have read all the Slashdot stories for at least the past week, so as to recognize obvious duplicates? I think it would be reasonable to expect them to search for duplicates for the past year, but that's just me.
How long before moderators can act on the stories themselves? Add a "-5 Repost" option...
- Peter
It is a phase-change technology -- instead of "burning" a dye layer as in CD-R, CD-RW melts a layer of metalic material.
If a spot of this material is heated above its melting point, and then allowed to cool very quickly, i.e. turn the laser on full and then turn it completely off, it solidifies in a kind of cloudy manner, refered to as the amorphous state. This happens because while melted, the various molecules float around in a random orientation. When cooled quickly, they are "frozen" in this random state. This makes that spot cloudy enough so that light isn't reflected clearly by the reflective layer below.
On the other hand, if you heat that same spot again to its melting point (full-power laser) but then let it cool slowly using a lower-power laser to keep it slightly heated, the moluecules have time to crystalize, lining up with each other to form a nice, clear crystal. When the laser finally turns all the way off, that spot is now frozen in this transparent state, no longer cloudy, so that light passes through and reflects brightly off the mirrored surface below.
The downsides are: The contrast between the cloudy==unreflective and clear==reflective states is not as great as a pressed CD or opaque-dye CD-R, so it takes a more sensitive reader. I believe that CD-RW capable readers specifically recognize that it's a CD-RW, and use different thresholds of brightness for determining 1s and 0s. That's why older players aren't compatible.
The other one is that this melting/solidifying process gradually damages the crystaline layer. After enough "meltings", it wears out and gets permanently cloudy.
HowStuffWorks.com has a nice article about CD-R and RW technology.
- Peter
http://www.linuxtelephony.com/
The earth is a natural dipole!!
:)
Right... and currently the Earth's magnetic north pole is near our geographic south pole.
Doesn't stay there for long, in geologic time frames, however. Our magnetic pole changes fairly regularly, according to geologists who care about such things.
No, I need to find a naturally occuring dipole that an Alien would be likely to find in another galaxy. One whose polarity I could describe unambiguously.
Tricky...
- Peter
Of course, if one stands in the northern hemisphere, looking at the sun, the definition of "left" and "right" is one way.
:)
Move to the southern hemisphere. You're now the other-side-up, and left and right are reversed.
This is now wandering off-topic even further, but: Have you every tried to define "left"? Pretend you're on the phone with aliens, who want to know what we define as "left".
Up, down are easy -- gravity based definitions are fine. But then try to describe clockwise, or right.
I come close when I have the alien move an electron in the "up" direction, and then try to define clockwise in terms of the direction of the magnetic field lines created.
But then you need a way to define the polarity of the magnetic field -- and I can't think of a naturally occuring magnetic dipole to compare it to.
Nasty brain twister, if you let yourself be kept up at night thinking about such things.
- Peter
How hard is it to make it a link?
h tml
http://www.msu.edu/~brownd41/mirror/gotfog/index.
- Peter
Specifically:
Still, 1000mW is a lot more than the unlicensed transmitters use.
- Peter, N0MNS
With Apple's "Airport" implementation, there seems to be a 200-300ms loss of connectivity -- if I'm using "ping -f" over the link I lose about 40-60 packets.
Carrying on a tcp transfer, there's at most a brief pause as a couple packets are retransmitted. Sometimes I don't notice a hiccup at all.
This is without any WEP turned on.... it might add some extra time.
A number of assumptions are at play: The access points you're crossing among are all on the same LAN segment, they all have the same "name"/SSID, and your network switches can handle the idea of an MAC address that was coming from one port suddenly coming from another -- most switches work fine. (Hubs wouldn't be an issue, obviously)
At least the way Apple implemented their clients, nothing in such a switch between same-SSID WAPs triggers interface up/down -- there's no DHCP request, everything stays the same.
Makes me wonder how the software posted about here deals with transitions between "cells" of a meshed network.
- Peter
I guess I can accept reposts a couple months after the fact, but just a couple DAYS?
:)
On tusday, Slashdot ran Earth: The Ring World
Or was that a special article that only I could see?
On the other hand, I'm really curious why Tuesday's article now has only 28 comments, while this current one, three days later, has well over a hundred. Both were in the Science section of slashdot... what am I missing?
- Peter
It's only mentioned briefly in the actual article as well:
So how do they know that one of these streams is made up of anti-electrons?
Ira Flatow is having a conversation about anti-matter on Science Friday as I'm typing this. It's a fascinating topic, so I always hate to see it just glossed over in press releases like this.
- Peter
I think his comment was that the actual stories on
- Peter
The decks have IEEE1394(Firewire) interfaces, and have a raw-data mode typically used for recording encrypted data from satellite broadcasts, so it will be trivial to write drivers to allow data storage and retrieval.
Now, I said "cheap" in the subject -- $1000 is already not bad for a 44GB media size, but if D-VHS takes off in the consumer market the prices will plummet!
Here's wishing it'd happen soon...
- Peter
The concept here is that all ER technicians will have the simple scanning device that will pull important medical data off the chip.
If you're unconscious, and the ER tech can just scan off you that you're diabetic and allergic to penicillin, that's a Good Thing.
Of course, conspiracy theorists say that every time you have surgery, the Government is implanting these in us without our knolwedge, and using it to track us. Oooooh!
Give me a break.
- Peter
Toward the end of the article they talk about the Pen's ability to use any surface.
In reality, it's an optical mouse head on the tip of a pen. It's not your typical pen-based input device.
Granted, this has some cool applications, but makes it very un-pen-like for cursor movement -- you'd be drawing on whatever surface just like you'd be moving a mouse, with no absolute positional control, just delta.
And all this has NOTHING to do with replacing a keyboard. Why did the article keep bringing that up? They didn't mention handwriting recognition at all, which would be the essential component.
Not to mention that keyboards would still be needed for high-speed data entry.
Has someone named this syndrome? The "Wow, this new technology will replace all the current technology, look, isn't it cool?"-syndrome that the mass news media falls into all the time.
- Peter