Follow Slashdot stories on Twitter

 



Forgot your password?
typodupeerror
×

Comment Re:Read the article to see how pathetic they are (Score 4, Informative) 137

An ISP that cannot handle their customers getting 100MB/day is not worth being named an ISP imho.
We are talking Wide Area Wireless Network here. You know, there are laws of physics that prevent you from achieving 100MB/day/user in a limited spectrum with cells covering 5 square kilometers.
Comparing mobile wireless network with fixed fiber or cable is simply silly.
Learn to use WiFi on top of a fast fiber/cable link.

And yes, I do wireless network engineering for living.

Comment Limits to Heat Engine Efficiency (Score 1) 570

No matter how ingenious a heat engine design is, an old Carnot theorem
http://en.wikipedia.org/wiki/Carnot's_theorem_(thermodynamics)
limits its efficiency
http://en.wikipedia.org/wiki/Heat_Engine#Efficiency
In practical terms the wiggle room to improve heat engines is small and will only provide incremental gains not sufficient to solve our energy problem. It will simply postpone it by few years.
The real inefficiency is a massive use of personal transport where a mass transit is much more economical.

Comment please, be accurate with dimentsions (Score 1) 184

According to Abdulaziz Alhaidari's calculations, if one were to roll up graphene into a nanotube, this could compactify dimensions (from the sheet's two down to the tube's one),...
The sentence above conveys a wrong impression that tube is one dimensional. Dimensionality of a tube is still the same as of the plane and it is still two. What is different is its topology. Tube has one one dimension with a topology of a line (infinite in both directions) and another one which is a circle and is compact. And it, indeed, could cause some strange effects like pseudo-mass.

Comment Re:Welcome to the third world (Score 1) 249

Russia, as a country with minimal rule of law and an average IQ of 96, qualifies as third-world...

Are you seriously suggesting that a country with an average IQ of 96 can win a World War II in Europe, sent first satellite (sputnik) into space followed by a first man in space, develop nuke and thermo-nuke weapons, keep the whole world on its toes for about half a century and all that with an average IQ of just 96. I do not want to be rude or disrespectful but I wonder what is your IQ?

Comment cheaper by a dozen (Score 1) 187

I do not think that $ by $ comparison is valid here.
Actually, GSM networking equipment for AT&T's network is cheaper to buy that similar CDMA equipment that Verizon and Sprint uses. GSM market is sooo much larger than CDMA so that the economy of scale plays nicely here. You might get further with 21B$ upgrading your GSM network than with 25B$ for CDMA.

Comment Re:Surprised? (Score 1) 214

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.

Comment Re:Why switch to openSuse? (Score 2, Informative) 207

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:-)

Comment Re:Invest (Score 1) 501

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?

Comment hold your horses (Score 5, Informative) 306

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.

Robotics

Submission + - military robot feeding off dead bodies

slonik writes: It has been reported in the news that Pentagon is working on a autonomous robot that harvest energy off any biomass including dead bodies found on a battle field. A bizarre combination of 19-the century mechanics, 21-st century AI and 20-th century horror movies.

Slashdot Top Deals

He has not acquired a fortune; the fortune has acquired him. -- Bion

Working...