Verizon conveniently forgets to mention that its version of 3G "1xEVDO" is rapidly going down the drain, no one else in the world (with little exception of select carriers in Korea) us using it. Verizon phones cannot roam anywhere in the world beccause of this aerial interface difference. Starting next year Verizon will be ditching its existing network and plunge head on into new brave and untested world of 3GPP LTE. I will observe this spectacle from a comfortable distance.
For those who don't know, Yast is basically the configuration tool for *everything* - repository and package management, network configuration, video driver configuration, user accounts, runlevel and login behavior, configuring a hypervisor, re-partitioning, managing GRUB... basically, it's a centralized management tool.
Your forgot to mention that Yast also manages Apache, Samba, security, sshd, printers/scanners, fax, network time ntp, etc. Pretty much Yast configures everything that is configurable:-)
> Seeing as you're sitting calmly at a computer and you still > didn't consider turning the damn engine off...
Never ever even think of turning engine off while driving in a modern car. If you do you will lose most of your car controls like power steering, power breaks, etc.
A full disclaimer is in order. I work for AT&T Research and my specialty is wireless. But here I offer my personal opinion and I do not speak for AT&T.
It is unfortunate, that too many technical people on slashdot, who should know better, still think that wireless cellular network is just another "series of tubes" that carry bits around (senator Stevens, anyone?). In reality wireless communications is very different from wireline (copper, fiber, cable) communications due to the physical nature of Radio Wave propagation in open media (air) versus transmission lines (copper, fiber, etc). It is basic physics and scarcity of useful spectrum that is responsible for most grievances of wireless users rather than "evil telcos". Your suggestion to increase cell tower density does not hold water and here is why:
(1) You cannot simply increase the density of cell towers to solve capacity problems. Modern cellular networks in densely populated areas like NYC are already interference limited. Just imagine a New York Stock exchange floor where every broker is shouting like crazy all the time and the noise is unbearable. Now you double the number of brokers on the floor and make them shout twice as loud. Would your network capacity increase? As a matter of fact, it would actually go down because noone can decode anything.
(2) Radio wave propagation characteristics put fundamental limits on what each user can do. Every bit sent to a user that is far away from his/her serving base-station (high RF path-loss) costs more in radio resources to a carrier than a bit sent to a user close-by because it has to occupy wider bandwidth (OFDM) or it would take more time slots (TDMA) or spreading codes (CDMA). Distant user takes radio resources away from other users and contribute harmful interference back to the system. That is why average user data rate is so different from its peak rate under ideal conditions.
(3) Unlike wireline networks, wireless is a shared medium with much less capacity due to shortage of useful spectrum. You can easily lay out fiber links with lots of excess capacity that nicely cushions peak load. Cellular wireless networks, on the other hand, run at much higher utilization and load levels and suffer from the ugliness of terrestrial radio wave propagation and interference.
There are some Good News though. New wireless technologies are coming. 3GPP LTE (Long Term Evolution) and WiMAX are two similar technologies that will squeeze some more juice from existing airways. But it would require huge capital expenses to roll out new networks. Moreover, IMHO user demand grows still faster that the capacity gains achieved by those technologies. More spectrum will be needed and it is very expensive and scarce. Someone will have to pay for all this, right?
In Russia a "professional holiday" is NOT a real holiday and it is NOT a day off. It is a mere sign of appreciation for a certain professional activity. You might hear nice words about your buddies on TV and Radio and you have one more reason to have some drinks that day. Most of "important" professions in Russia have their professional days -- from teachers, doctors all way to police and steel-mill workers. It is no surprise whatsoever that IT workers (aka programmers) get their professional day too.
The countries that have converted to SI are the countries that were late to the industrial revolution party.
Are you suggesting that Germany, Britain, France were late to industrial revolution party? By the way, metric system was established during France revolution, just couple decades after the US Declaration of Independence. Plenty of time to come on board, right?
For everything graphical like 2D/3D plots, complex drawings and even solid-body shapes in PDF format I would recommend "Asymptote: The Vector Graphics Language" http://asymptote.sourceforge.net/. After some learning curve (it is a full-blown interpreted programming language) I never looked back on anything else. Asymptote is GPL software and comes with good manual and tons of examples in the Internet.
Germany has reasonably strong consumer protection laws. She can "return" her merchandise to the seller for "full refund". In this case it amounts to unistalling the OpenOffice, deleting the installer, might be even taking a screen-shot of the message showing "uninstall complete" and send a polite and firm message to the scammers (optional).
Sorry, but you are wrong. Shannon Information Theory is universal and is applicable to any communication device including MIMO, etc. If you are really interested, there is plenty of good Info Theory books (Tomas & Cover; Galager, etc) that will help you in this area.
Please, for God's sake, do not take marketing "white papers" as source of scientific facts.
BTW, another frequently overlooked consequence of the Shannon Theory is that at any receiver a Signal-to-Noise-Radio per received information bit should be larger then -1.6dB for ANY technology. Communication engineering is, thus, squeezed simultaaneously by frequency and by power limitations. There is also interference which changes the playing field in dense deployments, but Slashdot is a wrong forum to discuss these issues in depth.
As someone who works in the field of wireless cellular physical layer (MIMO, FEC, etc.) I would offer a bit of a reality check. As a rule of thumb in a wireless mobile environment with large cells even with MIMO, LDPC or Turbo coding, advanced QAM modulation, etc one should not expect spectral efficiency more than 4 bits/second/Hertz for an average user. And even this number is optimistic and assumes low mobility speeds and low interference. For a 40MHz full-duplex channel (half the resources in uplink, half in downlink) one would optimistically expect 80Mbits/sec per cell downlink or uplink. This capacity will be shared amoung all the users served by the cell. If, as a user, you get 8Mbits/second sustained throughput, consider yourself lucky.
I checked the paper. It is overly simplified on many accounts. First of all, no respected physicist would ever use Imperial Measurement System (foot, mile, etc) in physics calculations. (I have no rational explanation of American fascination with outdated and illogical units.) Secondly and more importantly: a tiger is not a point-like-particle and its movement cannot be adequately described in the way used in the article. Some of the kinetic energy during its jump is transferred into rotation, movement of his body parts, etc. Unless all these complex interactions are properly accounted for, the problem is not solved. It is quite plausible, that the SF tiger did clear the fence but this paper's proof leaves a lot to be desired.
Perhaps you are alluding to the measure : bits/second/Hz/square km?
Well, the practical metric is bits/second/Hz/user. Ideally, each cell will serve small number of users at a high data rate. To achieve this goal, the cell coverage area should be smaller than in a typical "voice service" cell that can serve dozens of users at the same time.
The article is just plain wrong when it states that the 2.5GHz band is superior for data, it is not. Throughput is primarily dependent on bandwidth, so 20MHz at in the 700MHz spectrum will effectively carry the same amount of data as 20MHz in the 2500MHz spectrum.
As someone who professionally designs cellular networks I can tell you that for data services 20MHz at 2.5GHz is much better than the same 20MHz at 700MHz. The data rate is determined not only by the channel bandwidth but also by the amount of interference that is generated by neighboring base stations. This interference depends on the RF propagation characteristics. At 2.5GHz the RF signals die off much faster with the distance than at 700MHz. As a result your interference levels will be lower at 2.5GHz. The downside is, of course, that cell coverage area of each individual base station will get smaller and you have to deploy them at substantially higher density. Rule of thumb: for voice you are coverage limited and you want your 700MHz (or 850MHz, ATT, Verizon) and big cells. For data you want small cells and high frequency band (2 or 2.5GHz).
A solution to the FreeAgent spin-down problem was published on Ubuntu forums back in July 2007: http://ubuntuforums.org/showthread.php?t=494673 It works for me very well. Importantly, it does not disable disk's power control. Instead, it auto restarts the disk whenever needed.
Seems perfectly fair to me. The guy who invented the AR-15 aka M-16 gets a dollar for everyone that is made...Made him utterly rich. Thanks to the communist regime at the time when Mikhail Kalashnikov invented it he didn't get one cent. He was born a poor man, and died a poor man.
According to Wikipedia article http://en.wikipedia.org/wiki/Mikhail_Kalashnikov Mikhail Kalashnikov is still alive. And he is hardly a poor man either. He used to be president of the factory that manufactured AK-47. He was not stinking rich but he, indeed, enjoyed prosperity and name recognition throughout Rusia.
What will happen to a poor Joe Luser if his laptop with all his music gets lost or stolen and some kind soul uploads his 1000 music files onto P2P network. His name and email address is there for everyone to see. Apple and RIAA are after him. How will he prove himself innocent?
Could it be a desperate attempt of OLPC project to secure commitments from the 3-rd world governments? It is not a secret that Dr.Negroponte had difficulties to persuade targeted governments to cough up real money to buy XO machines. So far the responses do not go beyond polite "expressed interest". Does Negroponte really thinks that adding MS to the effort could help him to close the deals?
Everything was locked down by MAC address and every printer was given a specific IP address. Even the pc ports were locked by MAC address.
These days MAC address spoofing is a simple matter. This guy could have made his laptop to use printer's MAC address and printer's IP address. All this info is readily available via printer's "advanced setting menu".
Well, the first reaction of many people might be "O no, yet another scripting language finds it way from the obscurity into the lame light". Do we need an extra one if we already have Ruby, Python, Perl, Tcl, Scheme. And I say -- YES, Lua has its place, it is not redundant, it is not "me too" language. And here is why.
I have been expert Ruby coder for the last 5 years using Ruby for data modelling, extensive scripting, wrote load-balancing scripts, Rails Web development, binding C++ libraries to Ruby using SWIG, you name it.
Six month ago I got involved in LUA and I totally fell in love with it. What does make a beautiful programming language? Lots of features? wealth of libraries? simplicity of it? I think that language design is more art than science and the language beauty is the careful balance of features, simplicity, semantics, uniformity, etc. Like in a masterpiece painting it is the balance of color, shapes, motives and composition.
C, for example, ia a beautiful language in the category of "portable assemblers". In that category C is powerful thanks to its libraries, simple and easily implementable thanks to its syntax and semantics, portable due to very clever and clean hardware abstraction.
I think that Lua is to "high level scripting languages" is what C is to "portable assemblers". Lua has both OO and functional programming very naturally represented in its semantics. All objects are first class (including functions). Lua is small, very fast (in fact fastest scripting language according to http://shootout.alioth.debian.org/), has very good Virtual Machine, incremental Garbage Collector. As far as fundamantals are concerned, Lua is light-years ahead of Ruby. It still lags behind in library support, but the recent progress is very encouraging.
Anyway, give Lua a try. You will love it. Lua is nice, its codebase is tiny (about 10K lines). It runs on anything that support ANSI C compiler including embedded stuff (ARM, Palm, Cell phones, MIPS, x86, etc).
First of all, Plank constant is a unit of a quantity called "action" and is measured in Energy x Time (like JxS). Secondly, in high energy physics one is accustomed to so called natural units where velocity is measured as fractions of speed_of_light and Planck's constant value is chosen to be 1 (unit). This gives rise to a nice relations between units of time, length and mass. To cut it short if one can accurately measure time (with some nuclear clock) such measurements can be converted into measurements of mass or/and length.
Please, don't spread FUD around. You sound like Ericsson FUDers 5 years ago. CDMA (IS-95) *does* provide several times the capacity of GSM and order of magintude better capacity than analog (AMPS). Also the voice quality is better. This why CDMA has been chosen for the Third Generation of wireless standard (W-CDMA) and this is why Ericcson bought troubled Qualcomm Infrastructure division in the beginneing of this year.
Unfortunately many big boys from Telecom Industries quickly learned from Microsoft how to use FUD to attack better technologies. Your post is a good example of it.
Slashdot Mirror
Verizon conveniently forgets to mention that its version of 3G "1xEVDO" is rapidly going down the drain, no one else in the world (with little exception of select carriers in Korea) us using it. Verizon phones cannot roam anywhere in the world beccause of this aerial interface difference.
Starting next year Verizon will be ditching its existing network and plunge head on into new brave and untested world of 3GPP LTE. I will observe this spectacle from a comfortable distance.
For those who don't know, Yast is basically the configuration tool for *everything* - repository and package management, network configuration, video driver configuration, user accounts, runlevel and login behavior, configuring a hypervisor, re-partitioning, managing GRUB... basically, it's a centralized management tool.
Your forgot to mention that Yast also manages Apache, Samba, security, sshd, printers/scanners, fax, network time ntp, etc. Pretty much Yast configures everything that is configurable:-)
> Seeing as you're sitting calmly at a computer and you still
> didn't consider turning the damn engine off...
Never ever even think of turning engine off while driving in a modern car. If you do you will lose most of your car controls like power steering, power breaks, etc.
Mod the parent up! It is the best common sense solution every software engineer must know.
A full disclaimer is in order. I work for AT&T Research and my specialty is wireless. But here I offer my personal opinion and I do not speak for AT&T.
It is unfortunate, that too many technical people on slashdot, who should know better, still think that wireless cellular network is just another "series of tubes" that carry bits around (senator Stevens, anyone?). In reality wireless communications is very different from wireline (copper, fiber, cable) communications due to the physical nature of Radio Wave propagation in open media (air) versus transmission lines (copper, fiber, etc). It is basic physics and scarcity of useful spectrum that is responsible for most grievances of wireless users rather than "evil telcos". Your suggestion to increase cell tower density does not hold water and here is why:
(1) You cannot simply increase the density of cell towers to solve capacity problems. Modern cellular networks in densely populated areas like NYC are already interference limited. Just imagine a New York Stock exchange floor where every broker is shouting like crazy all the time and the noise is unbearable. Now you double the number of brokers on the floor and make them shout twice as loud. Would your network capacity increase? As a matter of fact, it would actually go down because noone can decode anything.
(2) Radio wave propagation characteristics put fundamental limits on what each user can do. Every bit sent to a user that is far away from his/her serving base-station (high RF path-loss) costs more in radio resources to a carrier than a bit sent to a user close-by because it has to occupy wider bandwidth (OFDM) or it would take more time slots (TDMA) or spreading codes (CDMA). Distant user takes radio resources away from other users and contribute harmful interference back to the system. That is why average user data rate is so different from its peak rate under ideal conditions.
(3) Unlike wireline networks, wireless is a shared medium with much less capacity due to shortage of useful spectrum. You can easily lay out fiber links with lots of excess capacity that nicely cushions peak load. Cellular wireless networks, on the other hand, run at much higher utilization and load levels and suffer from the ugliness of terrestrial radio wave propagation and interference.
There are some Good News though. New wireless technologies are coming. 3GPP LTE (Long Term Evolution) and WiMAX are two similar technologies that will squeeze some more juice from existing airways. But it would require huge capital expenses to roll out new networks. Moreover, IMHO user demand grows still faster that the capacity gains achieved by those technologies. More spectrum will be needed and it is very expensive and scarce.
Someone will have to pay for all this, right?
In Russia a "professional holiday" is NOT a real holiday and it is NOT a day off. It is a mere sign of appreciation for a certain professional activity. You might hear nice words about your buddies on TV and Radio and you have one more reason to have some drinks that day. Most of "important" professions in Russia have their professional days -- from teachers, doctors all way to police and steel-mill workers. It is no surprise whatsoever that IT workers (aka programmers) get their professional day too.
The countries that have converted to SI are the countries that were late to the industrial revolution party.
Are you suggesting that Germany, Britain, France were late to industrial revolution party?
By the way, metric system was established during France revolution, just couple decades after the US Declaration of Independence. Plenty of time to come on board, right?
For everything graphical like 2D/3D plots, complex drawings and even solid-body shapes in PDF format I would recommend "Asymptote: The Vector Graphics Language"
http://asymptote.sourceforge.net/. After some learning curve (it is a full-blown interpreted programming language) I never looked back on anything else.
Asymptote is GPL software and comes with good manual and tons of examples in the Internet.
Germany has reasonably strong consumer protection laws.
She can "return" her merchandise to the seller for "full refund".
In this case it amounts to unistalling the OpenOffice, deleting the installer, might be even taking a screen-shot of the message showing "uninstall complete" and send a polite and firm message to the scammers (optional).
Sorry, but you are wrong. Shannon Information Theory is universal and is applicable to any communication device including MIMO, etc. If you are really interested, there is plenty of good Info Theory books (Tomas & Cover; Galager, etc) that will help you in this area.
Please, for God's sake, do not take marketing "white papers" as source of scientific facts.
BTW, another frequently overlooked consequence of the Shannon Theory is that at any receiver a Signal-to-Noise-Radio per received information bit should be larger then -1.6dB for ANY technology. Communication engineering is, thus, squeezed simultaaneously by frequency and by power limitations. There is also interference which changes the playing field in dense deployments, but Slashdot is a wrong forum to discuss these issues in depth.
As someone who works in the field of wireless cellular physical layer (MIMO, FEC, etc.) I would offer a bit of a reality check. As a rule of thumb in a wireless mobile environment with large cells even with MIMO, LDPC or Turbo coding, advanced QAM modulation, etc one should not expect spectral efficiency more than 4 bits/second/Hertz for an average user. And even this number is optimistic and assumes low mobility speeds and low interference.
For a 40MHz full-duplex channel (half the resources in uplink, half in downlink) one would optimistically expect 80Mbits/sec per cell downlink or uplink. This capacity will be shared amoung all the users served by the cell. If, as a user, you get 8Mbits/second sustained throughput, consider yourself lucky.
I checked the paper. It is overly simplified on many accounts. First of all, no respected physicist would ever use Imperial Measurement System (foot, mile, etc) in physics calculations. (I have no rational explanation of American fascination with outdated and illogical units.) Secondly and more importantly: a tiger is not a point-like-particle and its movement cannot be adequately described in the way used in the article.
Some of the kinetic energy during its jump is transferred into rotation, movement of his body parts, etc. Unless all these complex interactions are properly accounted for, the problem is not solved. It is quite plausible, that the SF tiger did clear the fence but this paper's proof leaves a lot to be desired.
Perhaps you are alluding to the measure : bits/second/Hz/square km?
Well, the practical metric is bits/second/Hz/user.
Ideally, each cell will serve small number of users at a high data rate. To achieve this goal, the cell coverage area should be smaller than in a typical "voice service" cell that can serve dozens of users at the same time.
The article is just plain wrong when it states that the 2.5GHz band is superior for data, it is not. Throughput is primarily dependent on bandwidth, so 20MHz at in the 700MHz spectrum will effectively carry the same amount of data as 20MHz in the 2500MHz spectrum.
As someone who professionally designs cellular networks I can tell you that for data services 20MHz at 2.5GHz is much better than the same 20MHz at 700MHz. The data rate is determined not only by the channel bandwidth but also by the amount of interference that is generated by neighboring base stations. This interference depends on the RF propagation characteristics. At 2.5GHz the RF signals die off much faster with the distance than at 700MHz. As a result your interference levels will be lower at 2.5GHz. The downside is, of course, that cell coverage area of each individual base station will get smaller and you have to deploy them at substantially higher density. Rule of thumb: for voice you are coverage limited and you want your 700MHz (or 850MHz, ATT, Verizon) and big cells. For data you want small cells and high frequency band (2 or 2.5GHz).
Just my two cents from the tranches.
A solution to the FreeAgent spin-down problem was published on Ubuntu forums back in July 2007:
http://ubuntuforums.org/showthread.php?t=494673
It works for me very well. Importantly, it does not disable disk's power control. Instead, it auto restarts the disk whenever needed.
According to Wikipedia article
http://en.wikipedia.org/wiki/Mikhail_Kalashnikov
Mikhail Kalashnikov is still alive. And he is hardly a poor man either. He used to be president of the factory that manufactured AK-47. He was not stinking rich but he, indeed, enjoyed prosperity and name recognition throughout Rusia.
What will happen to a poor Joe Luser if his laptop with all his music gets lost or stolen and some kind soul uploads his 1000 music files onto P2P network. His name and email address is there for everyone to see. Apple and RIAA are after him. How will he prove himself innocent?
On the contrary, our brains themselves are massively parallel processing neuron networks.
Could it be a desperate attempt of OLPC project to secure commitments from the 3-rd world governments? It is not a secret that Dr.Negroponte had difficulties to persuade targeted governments to cough up real money to buy XO machines. So far the responses do not go beyond polite "expressed interest". Does Negroponte really thinks that adding MS to the effort could help him to close the deals?
Just my two cents.
Everything was locked down by MAC address and every printer was given a specific IP address. Even the pc ports were locked by MAC address.
These days MAC address spoofing is a simple matter. This guy could have made his laptop to use printer's MAC address and printer's IP address. All this info is readily available via printer's "advanced setting menu".
--slonik--
Well, the first reaction of many people might be
"O no, yet another scripting language finds it way from the obscurity into the lame light". Do we need an extra one if we already have Ruby, Python, Perl, Tcl, Scheme. And I say -- YES, Lua has its place, it is not redundant, it is not "me too" language. And here is why.
I have been expert Ruby coder for the last 5 years using Ruby for data modelling, extensive scripting, wrote load-balancing scripts, Rails Web development, binding C++ libraries to Ruby using SWIG, you name it.
Six month ago I got involved in LUA and I totally fell in love with it.
What does make a beautiful programming language? Lots of features? wealth of libraries? simplicity of it? I think that language design is more art than science and the language beauty is the careful balance of features, simplicity, semantics, uniformity, etc. Like in a masterpiece painting it is the balance of color, shapes, motives and composition.
C, for example, ia a beautiful language in the category of "portable assemblers". In that category C is powerful thanks to its libraries, simple and easily implementable thanks to its syntax and semantics, portable due to very clever and clean hardware abstraction.
I think that Lua is to "high level scripting languages" is what C is to "portable assemblers". Lua has both OO and functional programming very naturally represented in its semantics. All objects are first class (including functions). Lua is small, very fast (in fact fastest scripting language according to http://shootout.alioth.debian.org/), has very good Virtual Machine, incremental Garbage Collector. As far as fundamantals are concerned, Lua is light-years ahead of Ruby. It still lags behind in library support, but the recent progress is very encouraging.
Anyway, give Lua a try. You will love it. Lua is nice, its codebase is tiny (about 10K lines). It runs on anything that support ANSI C compiler including embedded stuff (ARM, Palm, Cell phones, MIPS, x86, etc).
First of all, Plank constant is a unit of a quantity called "action" and is measured in Energy x Time (like JxS).
Secondly, in high energy physics one is accustomed to so called natural units where velocity is measured as fractions of speed_of_light and Planck's constant value is chosen to be 1 (unit). This gives rise to a nice relations between units of time, length and mass. To cut it short if one can accurately measure time (with some nuclear clock) such measurements can be converted into measurements of mass or/and length.
Please,
don't spread FUD around. You sound like Ericsson
FUDers 5 years ago. CDMA (IS-95) *does* provide several times the capacity of GSM and order of magintude better capacity than analog (AMPS). Also the voice quality is better.
This why CDMA has been chosen for the Third Generation of wireless standard (W-CDMA) and this is why Ericcson bought troubled Qualcomm Infrastructure division in the beginneing of this year.
Unfortunately many big boys from Telecom Industries quickly learned from Microsoft how to use FUD to attack better technologies.
Your post is a good example of it.
--slonik
PS: don't speek without data