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Comment Re:AC current maintained only by tradition? (Score 1) 578

The "war of the currents" was won by AC because at the time AC voltage conversion (transformer) was much simpler and more effcient than DC voltage conversion (motor-generator set). Efficient voltage conversion is nessacery for large scale electrification to work because without it either end use voltages are too dangerous or resitive lesses are crippling.

However taking a more modern look things are not so clear cut, certainly both DC and AC transmission and distribution systems are now feasible. Each has pros and cons.

Pros for DC
1: pretty much all current flow represents real transfers of power from source to load, unlike in AC systems where reactive and hardmonic currents inevitablly flow due to the characteristics of loads and the inductance and capacitance of cables
2: there is no need to synchronise generators before paralelling them
3: the peak voltage is equal to the rms voltage. Since insulation requirements are generally determined by peak voltage a DC system can operate at a higher RMS voltage for a given insulation thickness/insulator size.

Pros for AC:
1: large installed base of equipment which brings economies of scale and compatibility
2: much less prone to sustaining arcs which makes switches and circuit breakers much cheaper and unplugging stuff without turning off first much safer.
3: while voltage conversion of DC is now possible with reasonablly high efficiency the converters require complex power electronics. I'm sure a DC equivilent of a "pole pig" is feasible but I would expect it to be considerablly more expensive and probablly less reliable.

Comment Re:Netflix says "nothing has changed on our end" (Score 1) 437

NetFlix should be able to implement end-to-end security that makes sure the target device belongs to a USA IP address, even when a VPN is deployed.

They can verify that the traffic they receive and send comes from/goes to an IP address that is registered in the US. What a VPN does is allow the device to be moved outside the US while keeping the place it's packets appear on the internet from in the US. The VPN software need not be on the client device itself, it can be on a seperate system that acts as the client devices default gateway if desired/needed. I guess they could try looking at latency and assume anyone with an unexplained high latency was using a VPN but I expect the false positive rate would be unacceptable.

They can mess with the "partial VPN" soloutions (which are popular because they are cheaper and more conviniant than forcing all the traffic through a VPN) and they can block known VPN providers but there isn't a whole lot they can do against a "full traffic" VPN with it's endpoint located on a non-suspiscious US network.

Comment Re:AC current maintained only by tradition? (Score 1) 578

The key to remember which V, I and R you are talking about.

In a DC or single phase AC system* your cable is essentially** a pair of resistors in series with the load. Current through the resistors represending the cable the same as current through the load. Voltage accross the resistors representing the cable is not determined by voltage across the load.

For a given load power higher voltage means lower current which means less resistive loss for a given cable size (or alternatively a smaller cable size for the same loss).

* Things get a little more complex with 3 phase AC but the principles hold.
** Ignoring leakage

Comment Re:Chinese that speak English (Score 1) 578

For example when a French or Chinese air traffic controller is communicating with an aircraft of their own nationality it must be in English, so that all the traffic which is listening on the same channel knows what is going on.

Do you have a source for that claim? it contradicts wikipedia which claims "Pursuant to requirements of the International Civil Aviation Organization (ICAO), ATC operations are conducted either in the English language or the language used by the station on the ground.[2] In practice, the native language for a region is normally used; however, the English language must be used upon request.[2]" http://en.wikipedia.org/wiki/A...

Comment Re:Meanwhile... (Score 1) 578

UTF-16 is a system for "shoehorning" modern unicode into systems designed arround early unicode (e.g. Java, The NT line of windows) in the same way that UTF-8 is a system for "shoehorning" unicode into systems designed around sequences of bytes where values 0-127 are ASCII and values 128-255 are something vendor/locale specific.

The main downside of UTF-16 is because the multi-unit case is much rarer than in UTF-8 bugs regarding it are much less likely to be noticed and dealt with early.

Comment Re:Chinglish (Score 1) 578

The rarely used meaning relates to the last, with lead meaning a cord used with animals to guide them - but even that definition is a derivative use of the 2nd.

there appears to be a difference between British english and american english here. Here in england we would normally call the thing used to guide/control animals a "lead" (e.g. you will see signs saying "keep your dog on a lead")while americans seem to preffer the term "leash" (at least that is my experiance from watching american shows on animal planet)

We brits also use the term lead to refer to other cords, for example "mains lead" (power cord in american english) or "extension lead" (extension cord in american english)

Comment Re:Did these fly from Area 51? (Score 1) 197

Also people subconsciously process the images from their eyes and this processing can sometimes mislead the conscious brain. In particular we take the 2D images from our eyes and process them into a 3D scene. Unfortunately a 2D image does not directly tell us the size of or distance to an object, merely the angle the object takes up in the view. This angle is roughly proportional to size/distance.

The brain uses several cues to try and resolve this ambiguity.
1: binocular vision, this works great at short distances but it quickly falls off in effectiveness as the distance between the eyes becomes negligable compared to the distance to the object.
2: position in the scene, if the object is on a surface then the brain can use it's mental model of the surface to resolve the distance to the object and hence work out the size. but this doesn't apply to a flying object
3: occlusion, if one object can be seen to be behind another that gives an obvious cue about thier respective distance. Unlikely to apply to flying objects though since the only thing occluded is likely to be clouds and the average person has no mental feel for the distance to those.
4: expected size of the object, this is about the only one left for flying objects.

So if people expect flying saucers to be huge they will see them as huge, even if in reality they are just someone playing a prank with an RC model.

Comment Re:Cheaper (Score 1) 349

If an origin/destination pair has lots of competition the prices will be driven down to a level not much higher than the cost. If it has little to no competition the price will likely be set much higher.

Since there are often multiple routes between major locations there is likely to be more competition on the multi-hop journeys between major locations than on journeys to/from the more minor locations on the way.

Comment Re:HDD Advantage (Score 3, Interesting) 190

BINGO

The underlying issues with flash can be and are successfully hidden by the controllers in modern SSDs for most workloads (very heavy write loads can be problematic) but that hiding comes at a price. The firmware in a SSD is far more complex than an a HDD and so for a given level of engineering effort it will be less reliable. In particular i've noticed corruption after unclean shutdown to a far greater extent on SSDs than HDDs.

Comment Re:Who cares about rotational speed these days? (Score 1) 190

AIUI the microservers in question have five SATA ports and one eSATA port on the motherboard. They also have a PCIe slot that you can use.

http://www.icydock.com/icy_tip...

Looks like you have to watch your models though, it seems the latest generation have moved to using slimine optical drives :(

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