Phase speed is the speed at which wavefronts move through the medium, and it isn't limited by the speed of light. A techie example of a phase speed is the speed at which text scrolls across a rolling LED sign (we've all seen them). You can make the text scroll as fast as you like, in principle, because individual LEDs don't have to communicate with one another -- they just turn on and off at set times. You can even make the text scroll faster than light!
Um, no, you can't. If the signal to turn on a led has to get from one end of the device to the other, that signal can't travel faster than c. Electrical impulses are also limited by this.
If you're thinking, 'well, lets just put the signal generators at both sides' that won't get you anywhere, because you still have to synchronize the two, which will be off by a factor depending on the length of electrical path. Either way you cut it, I don't think you can do it.
How is this different than having a serial number on the paper? They still have to do something external for them to tie it back to you. I would generally consider either one anonymous enough, unless they ask for a credit card or name or something, of course.
I *just* bought a Vx last week, and even with these new ones, I'm not sorry I did. Couple reasons. 1. that SDMI slot looks evil. 2. USB connectivity is proprietary.
That is, Palm (unlike Handspring) won't release the specs on the USB protocol they are using in their USB cradles. This was an issue with the later models of the Vx, as they also have USB cradles.
In a nutshell: Currently, there is no way to connect a Palm-brand PalmOS device with a USB connector with Linux. Sucks.
He put a random number generator in the definition of the thing, so is it really surprising that the output is random?
I'd say yes. Take the flip of a coin, a very basic random number generator. You know what the probability is of it being heads if it is a fair coin. It's 0.5.
He's saying that he can't find the actual probability that any given program will halt or not. He's saying that probability is 'maximally unknowable'.
I don't have a big formal math background, but I think i was able to pick up what he says in the lecture transcript.
The interesting point of the matter deals with Turing machines and the halting problem. If you have a well defined turing machine, it will either halt or not depending upon its input (the program). Turing's idea was that you can't determine beforehand whether a given program will halt (for all possible programs). That is, the only guranteed way to see if a program halts or not is to run it. If it halts in the time you observe it, good. If not, then will it halt in n+1 time? Unknown.
Chaitin defines W as "the probability that a program generated by tossing a coin halts." And he says that this W will be a real number between 0 and 1 that is well-defined. He says once you define the language of the turing machine, W becomes well defined. He then claims that W is 'maximally unknowable' - that is, it is irrational like PI and e, having no mathematical structure. But it is not just irrational, he says that you can't generate W like e or PI from a formula.
You can get it in the limit from below, but it converges very, very slowly --- you can never know how close you are --- there is no computable regulator of convergence, there is no way to decide how far out to go to get the first N bits of W right.
He also claims that W is 'irreducible information' - it cannot be compressed because it is truly random.
From here it gets pretty complex, but my understanding of it is that this introduces true randomness into pure mathematics, which people think shakes things up quite a bit. He compares it to the introduction of quamtum mechanics into Physics.
Oh, so its perfectly OK that if I use their software, they restrict my speech on what I can say about that software? No way in hell! They and all the other major db vendors that pull the same stunt can shove their EULAs where the sun don't shine!
Am I the only one here that thinks that a C|Net article on OCing has no bearing to most of the slashdot community? C|Net has a reputation for barely technical articles, glossing over subjects and missing out on all the important details. The real details are available (and have been for a long time) on sites like AnandTech, Tom's Hardware and others. Besides, most of the/. crowd already knows about overclocking and is not going to benefit from a story like this. This is not news for nerds. This is not stuff that matters. If I could moderate this story, it would definately get a -1, Redundant.
The Rochester Institute of Technology (RIT) has a Software Engineering program that will graduate its first class this May. It is a spin-off of the CS department. (See also here)
Anyone had any luck getting DOS door games running under linux? DOSemu? Howabout DOSemuing a whole BBS? Does this work? How do you do telnet access? Some wierd-o FOSSIL driver or something? I'd be curious, and might even setup something if it is feasible.
I've never heard of Rute before, but thanks for the MLP. That is one hell of a piece of documentation.
What about the new California system??
on
eLection '04
·
· Score: 2
Check it out here. Polling places use computers and a private network to relay vote tallys. I also heard that they use a touch screen computer display to actually cast their ballots, but I havn't seen any reports confirming this.
I just wanted to point something out here. While I agree this does seem to be a good endorsement for Linux's role, I have to wonder about some of these conclusions. One in particular was interesting to me:
7. The performance advantages of RISC over Intel-based servers will decline by about 20 percent to 30 percent each year [..]
They mention nothing to back this up, and it just plain doesn't make sense to me. This kind of conclusion without any presentation of a reason behind if makes me take this whole report with a grain of salt.
The P6 processors have microcode that you can change at runtime. However, these changes DO NOT GET SAVED ACCROSS POWER CYCLES . This is used by Intel to fix some errata in the shipping microprocessor. The way it is implemented, since it is not written permanently, the system BIOS has to write microcode updates to the CPU at boot time, on every reboot. This enables Intel to make revisions take effect with simple BIOS updates that everyone is used to. This was very interesting for me, as I had no idea that BIOS updates held such weight with the P6 family of processors!
If you look at the PPro Processor Specification Update (the accompanying PDF), you will see that some of the erratum are marked as: "Workaround: It is possible for BIOS code to contain a workaround for this erratum." This indicates an erratum that can be fixed by microcode updates.
The advantage to having this is significant, in my opinion. You don't have to buy a new processor stepping to get erratum fixed. Granted, there will be plenty of erratum that can't be fixed with a microcode change, but this is at least a step in the right direction.
As was pointed out by another poster, Linux 2.4 has/dev/microcode support for P6 processors. What this allows you to do is update your microcode on boot. Why would you want to do this? Intel issues new microcode updates to the BIOS writers. If you get your hands on new microcode before there is a full flashable BIOS revision available, this will allow you to install the new microcode at bootup, removing one layer of your dependency on your BIOS writer.
Anyway, I think this shit is really cool, but not something I plan on using unless there is a serious errata found in my processor that can be fixed this way. It sounds like quite a bit of hastle for marginal benefit in most cases. However, its great that Linux provides us this option.
Anyone have any ideas about hacking microcode? I donno if Intel releases specs on it. Could be very interesting.
That could be a good reason to stick with GNUmeric and pico.
Pico?! Are you kidding me? What a useless text editor! You could at least say emacs or vim. What kind of self-respecting geek uses pico?
Whenever you walk by a computer and see someone using pico, be kind. Pause for a second and remind yourself that: "There, but for the grace of God, go I." -- Harley Hahn
With Linux 7.0, SuSE has made a series of improvements to the Linux kernel that could (unofficially) be called 2.2.17, thanks to a variety of extensions.
If anything is going to push these to market, its going to be the Internet porn business. "Now available for download, $50.99, Sylvia Saint's Pelvis in Postscript-3D"
SPECfp2000 results are available for the UltraSparc-III 900 MHz. It scored a 482. Pretty damn quick, especially when you consider that its score is more than 50% higher than the Pentium-III 933 Mhz, which got a 305.
Of course, if you consider cost, it nearly evens out.. but people don't buy Suns cause they are cheap.
Wow, thats rediculously stupid. Here we are with all these modern digital phones and we are using ancient tech to trasmit data. How dumb. Thanks for clearing that up for me.
The main reason for this is the kind of network the two use; WAP uses circuit switched network while i-Mode uses packet switched data network, which is more suited to transferring data than circuit switched networks. Also, the packet based network contributes to the ?always on? nature of the i-Mode
I can't believe WAP uses real circuit switched networks! This has to be a misunderstanding of this author. I don't know the details of WAP, but can anyone confirm that it doesn't use circuit switched networks? Perhaps the author misinterpreted something.. perhaps WAP phones make a dedicated connection to a WAP server for a certain amount of time, and the author interpreted that as circuit switched. Any know know any details?
(OT): Web sites requiring 'x' to view pages
on
Lego Mindstorms DJ
·
· Score: 1
When I go to this link, thanks to junkbuster my cookies are blocked and I get this:
No cookie.
To access this site your browser must be accepting cookies.
Why oh why do they make these pages cookie dependant? Howabout javascript? Just as annoying and even more common. God forbid I should want to web browse with Lynx or something else without javascript support. The cookies really annoy me. I *might* be able to understand wanting to track people around your site or whatever, but damnit, it shouldn't totally preclude viewing the page! Tons of sites do this.. mindstorms.lego.com is not alone. Try www.staples.com or a hundred others. Why don't people follow standards? There are reasons they exist!
</rant>
sorry for that tirade.. but i'm just not going to look at sites like this anymore.
Slashdot Mirror
Phase speed is the speed at which wavefronts move through the medium, and it isn't limited by the speed of light. A techie example of a phase speed is the speed at which text scrolls across a rolling LED sign (we've all seen them). You can make the text scroll as fast as you like, in principle, because individual LEDs don't have to communicate with one another -- they just turn on and off at set times. You can even make the text scroll faster than light!
Um, no, you can't. If the signal to turn on a led has to get from one end of the device to the other, that signal can't travel faster than c. Electrical impulses are also limited by this.
If you're thinking, 'well, lets just put the signal generators at both sides' that won't get you anywhere, because you still have to synchronize the two, which will be off by a factor depending on the length of electrical path. Either way you cut it, I don't think you can do it.
How is this different than having a serial number on the paper? They still have to do something external for them to tie it back to you. I would generally consider either one anonymous enough, unless they ask for a credit card or name or something, of course.
I *just* bought a Vx last week, and even with these new ones, I'm not sorry I did. Couple reasons. 1. that SDMI slot looks evil. 2. USB connectivity is proprietary.
That is, Palm (unlike Handspring) won't release the specs on the USB protocol they are using in their USB cradles. This was an issue with the later models of the Vx, as they also have USB cradles.
In a nutshell: Currently, there is no way to connect a Palm-brand PalmOS device with a USB connector with Linux. Sucks.
I'd say yes. Take the flip of a coin, a very basic random number generator. You know what the probability is of it being heads if it is a fair coin. It's 0.5.
He's saying that he can't find the actual probability that any given program will halt or not. He's saying that probability is 'maximally unknowable'.
The interesting point of the matter deals with Turing machines and the halting problem. If you have a well defined turing machine, it will either halt or not depending upon its input (the program). Turing's idea was that you can't determine beforehand whether a given program will halt (for all possible programs). That is, the only guranteed way to see if a program halts or not is to run it. If it halts in the time you observe it, good. If not, then will it halt in n+1 time? Unknown.
Chaitin defines W as "the probability that a program generated by tossing a coin halts." And he says that this W will be a real number between 0 and 1 that is well-defined. He says once you define the language of the turing machine, W becomes well defined. He then claims that W is 'maximally unknowable' - that is, it is irrational like PI and e, having no mathematical structure. But it is not just irrational, he says that you can't generate W like e or PI from a formula.
He also claims that W is 'irreducible information' - it cannot be compressed because it is truly random.
From here it gets pretty complex, but my understanding of it is that this introduces true randomness into pure mathematics, which people think shakes things up quite a bit. He compares it to the introduction of quamtum mechanics into Physics.
Oh, so its perfectly OK that if I use their software, they restrict my speech on what I can say about that software? No way in hell! They and all the other major db vendors that pull the same stunt can shove their EULAs where the sun don't shine!
Am I the only one here that thinks that a C|Net article on OCing has no bearing to most of the slashdot community? C|Net has a reputation for barely technical articles, glossing over subjects and missing out on all the important details. The real details are available (and have been for a long time) on sites like AnandTech, Tom's Hardware and others. Besides, most of the /. crowd already knows about overclocking and is not going to benefit from a story like this. This is not news for nerds. This is not stuff that matters. If I could moderate this story, it would definately get a -1, Redundant.
The Rochester Institute of Technology (RIT) has a Software Engineering program that will graduate its first class this May. It is a spin-off of the CS department. (See also here)
Anyone had any luck getting DOS door games running under linux? DOSemu? Howabout DOSemuing a whole BBS? Does this work? How do you do telnet access? Some wierd-o FOSSIL driver or something? I'd be curious, and might even setup something if it is feasible.
Not only is this old news, but its old news that was covered by Slashdot before!
This Slashback announced it on September 26 (albeit without confirmation).
And this Kuro5hin story featured it on October 19th, after the solution was confirmed, complete with a link to the solution details (PDF) !!
Holy cow.
I've never heard of Rute before, but thanks for the MLP. That is one hell of a piece of documentation.
Check it out here. Polling places use computers and a private network to relay vote tallys. I also heard that they use a touch screen computer display to actually cast their ballots, but I havn't seen any reports confirming this.
Also, California is apparently running non-binding on-line voting demonstrations.
I just wanted to point something out here. While I agree this does seem to be a good endorsement for Linux's role, I have to wonder about some of these conclusions. One in particular was interesting to me:
7. The performance advantages of RISC over Intel-based servers will decline by about 20 percent to 30 percent each year [..]
They mention nothing to back this up, and it just plain doesn't make sense to me. This kind of conclusion without any presentation of a reason behind if makes me take this whole report with a grain of salt.
um, hello? Unless we're talking about frozen methane or some other weirdness, glaciers = water.
PCs need video cards to POST. I donno about other platforms.
The P6 processors have microcode that you can change at runtime. However, these changes DO NOT GET SAVED ACCROSS POWER CYCLES . This is used by Intel to fix some errata in the shipping microprocessor. The way it is implemented, since it is not written permanently, the system BIOS has to write microcode updates to the CPU at boot time, on every reboot. This enables Intel to make revisions take effect with simple BIOS updates that everyone is used to. This was very interesting for me, as I had no idea that BIOS updates held such weight with the P6 family of processors!
/dev/microcode support for P6 processors. What this allows you to do is update your microcode on boot. Why would you want to do this? Intel issues new microcode updates to the BIOS writers. If you get your hands on new microcode before there is a full flashable BIOS revision available, this will allow you to install the new microcode at bootup, removing one layer of your dependency on your BIOS writer.
If you look at the PPro Processor Specification Update (the accompanying PDF), you will see that some of the erratum are marked as: "Workaround: It is possible for BIOS code to contain a workaround for this erratum." This indicates an erratum that can be fixed by microcode updates.
The advantage to having this is significant, in my opinion. You don't have to buy a new processor stepping to get erratum fixed. Granted, there will be plenty of erratum that can't be fixed with a microcode change, but this is at least a step in the right direction.
As was pointed out by another poster, Linux 2.4 has
Anyway, I think this shit is really cool, but not something I plan on using unless there is a serious errata found in my processor that can be fixed this way. It sounds like quite a bit of hastle for marginal benefit in most cases. However, its great that Linux provides us this option.
Anyone have any ideas about hacking microcode? I donno if Intel releases specs on it. Could be very interesting.
That could be a good reason to stick with GNUmeric and pico.
Pico?! Are you kidding me? What a useless text editor! You could at least say emacs or vim. What kind of self-respecting geek uses pico?
Whenever you walk by a computer and see someone using pico, be kind. Pause for a second and remind yourself that: "There, but for the grace of God, go I." -- Harley Hahn
This box is a 486, and is rather slow and old. It's connected to the internet with a 56k modem, and is located in Shrivenham, Wiltshire, England.
Having your 56k 486 slashdotted must really ruin your day.
With Linux 7.0, SuSE has made a series of improvements to the Linux kernel that could (unofficially) be called 2.2.17, thanks to a variety of extensions.
Um. Hello? Anyone awake in Germany?
Why not use the real 2.2.17 kernel?
If anything is going to push these to market, its going to be the Internet porn business. "Now available for download, $50.99, Sylvia Saint's Pelvis in Postscript-3D"
Talk about netsex.
Heh
Hey, thanks for the info and the correction. That definitely deserves a +5. Next time, I'll know to compare the base values.
SPECfp2000 results are available for the UltraSparc-III 900 MHz. It scored a 482. Pretty damn quick, especially when you consider that its score is more than 50% higher than the Pentium-III 933 Mhz, which got a 305.
Of course, if you consider cost, it nearly evens out.. but people don't buy Suns cause they are cheap.
Wow, thats rediculously stupid. Here we are with all these modern digital phones and we are using ancient tech to trasmit data. How dumb. Thanks for clearing that up for me.
The main reason for this is the kind of network the two use; WAP uses circuit switched network while i-Mode uses packet switched data network, which is more suited to transferring data than circuit switched networks. Also, the packet based network contributes to the ?always on? nature of the i-Mode
I can't believe WAP uses real circuit switched networks! This has to be a misunderstanding of this author. I don't know the details of WAP, but can anyone confirm that it doesn't use circuit switched networks? Perhaps the author misinterpreted something.. perhaps WAP phones make a dedicated connection to a WAP server for a certain amount of time, and the author interpreted that as circuit switched. Any know know any details?
When I go to this link, thanks to junkbuster my cookies are blocked and I get this:
No cookie.
To access this site your browser must be accepting cookies.
Why oh why do they make these pages cookie dependant? Howabout javascript? Just as annoying and even more common. God forbid I should want to web browse with Lynx or something else without javascript support. The cookies really annoy me. I *might* be able to understand wanting to track people around your site or whatever, but damnit, it shouldn't totally preclude viewing the page! Tons of sites do this.. mindstorms.lego.com is not alone. Try www.staples.com or a hundred others. Why don't people follow standards? There are reasons they exist!
</rant>
sorry for that tirade.. but i'm just not going to look at sites like this anymore.