Please create an account to participate in the Slashdot moderation system


Forgot your password?
Slashdot Deals: Cyber Monday Sale Extended! Courses ranging from coding to project management - all eLearning deals 20% off with coupon code "CYBERMONDAY20". ×

Comment If the ADC is more precise than needed (Score 1) 214

From my understanding, typically when you get random noise from the environment, you aren't exactly sampling the -actual- stuff -- there may not be any sounds, for example. Quiet rooms are not unusual. What you do is what an anonymous coward mentioned - you have a sensor that reads the temperature as 72.7230283037 degrees F. It's not REALLY that accurate, the last few digits are basically random. Maybe the light sensor says 43.584723028 lux, plus or minus 3 lux. It has more -precision- than it has -accuracy-. The decimal part is bullshit, random.

Obviously the device has to convert the analog measurement into a digital number that the CPU can manipulate. It uses an analog-to-digital converter to do this. A typical ADC might convert the reading from a microphone into an 8-bit integer, ranging from 0 (approximately silent) to 255 (very loud). A 16-bit ADC gives a range from 0-65,535. Phone calls traditionally use an 8-bit ADC because that's sufficient for voice. Voice calls don't have to be hi-fi, especially after you remove the highest and lowest frequencies which actually hinder intelligibility.

It would be wasteful for the manufacturer to use a 24-bit ADC on the microphone if they're only going to use 8 bit samples for phone calls, so they may only use an 8-bit ADC. In that case, the range of loudness is only 0-255, with no decimals, meaning any quiet room will register 0. There are no extra extra digits with "random" values. If the manufacturer intended to use it as a source of randomness they could use a 24-bit or 32-bit ADC, knowing that the smallest bits will be roughly random.

Comment computers are manufactured and LESS random (Score 1) 214

See the comment directly above yours,

Computers are actually -less- random that things like dice. To get a really good random number into a computer, one often connects it to some physical process. A camera pointed at a lava lamp is a well-known illustrative example. Computers are, at their heart, calculators, everything they do is reduced to simple math. And 1 + 1 always equals 2, every single time; there's nothing random about what a computer does. That's why when generating crypto keys it asks you to type on the keyboard and move the mouse - because the user can make random movements. The computer can't do random.

Further, you can inspect my dice, how do you inspect my rPi and know I haven't coded it to roll 8 more often than it should? You can look at -some- source code, but how do you know that's the source of the program I'm running? Confirming that is much more difficult than looking at a pair of dice.

Comment except they don't. Voltage of 120 batteries (Score 1) 196

You COULD use 7,000 cells at 3.7 volts each in series to get 25,800 volts. As you know, they run at 480V or so - the voltage of 120V lithium ion cells, as I originally said. So no, that's NOT a reason to use hundreds of little batteries rather than 100 much larger ones.

GP is also wrong, the maximum charge rate of lithium ion (in amps) is approximately equal to the capacity of the cell in amp-hours. That is to say, you can charge a lithium ion cell in an hour (plus safety factor) no matter what size it is. Two 500ma cells do NOT charge faster than one 1000ma cell. It takes an hour to charge, regardless of size.

Comment "Advanced battery technology" is a flashlight batt (Score 3, Interesting) 196

I knew that power tools and laptops used 18650 cells, which are slightly larger than AA batteries. Given the hype about "Tesla's advanced battery technology", I'm pretty surprised to learn the Tesla battery is also simply 7,000 flashlight batteries.

I see that the Tesla battery pack weighs 1,200 pounds. Reducing weight greatly improves efficiency, handling, braking, and acceleration, meaning lighter weight is all around better. It seems a bit wasteful of weight and materials to have 7,000 metal casings around 7,000 tiny batteries, connected with thousands of connections, rather far fewer larger cells. I'm surprised they don't use perhaps 24 or 100 larger cells instead, thereby eliminating thousands of unnecessary casings and connections.

Comment That's interesting (Score 1) 94

That's an interesting situation. I can certainly see a VPN with a port forward as being a reasonable solution, especially if you need a lot of storage. I'm assuming your ISP doesn't -also- offer IPv6 as well as the NAT IPv4.

SSH port forwarding is a fast, easy way to set up a VPN with port forwarding in one command. Even if you don't use it for this purpose, it's a good tool to have in your toolbox. It requires that you have a shell account internet-facing box, which might be a $5/month web hosting account. On Linux, Mac, Unix, BSD etc the command is:
ssh -R 2121:localhost:21

That means connecting to port 2121 on actually connects to port 21 on your local machine. On Windows, you can use puTTY to SSH, including port forwards:
SSH port forwarding is very flexible and you can set up new ports with one quick command. That flexibility does mean the syntax takes some getting used to. For a long time I used a script like this on my Mac to make it accessible from an internet-facing IP:

while ssh -R 2222:localhost:22
      sleep 30

If you have a recent iPad, there are Lightning flash drives that clip over the iPad.

A 50 GB "web hosting" account from provides FTP and http for $5-$10/month.

Comment see Rule of Capture (Score 1) 213

It is called the Rule of Capture in English, and has been recognized common law in British empire for hundreds of years. The first known written statute stating the principle was from Sparta, over a thousand years ago.

An interesting and well-known case on the application of Rule of Capture in America is Pierson v. Post.

Comment designed & marketed for specific unlawful purp (Score 1) 20

Other courts have noticed that Pirate Bay is called PIRATE Bay, and it is designed and marketed for a specific purpose, an unlawful one. A gun just a priced of metal, right? Under laws the laws of most countries, it's a piece of metal with a specific intended use, and it's regulated based on that.

One might argue that copyright terms are too long in many countries; you could even make an argument against copyright protection at all (though the argument doesn't fair well in the face of facts). You can't make a coherent argument that Pirate Bay isn't for pirating - for violating the -legal- rights of others. That makes it inherently different from Google or any general search engine.

Comment ownership of an object, sovereignty over territor (Score 5, Insightful) 213

There are two distinct issues here. First, the common law says that if a person harvests a wild animal, plant, or other thing, it is his to eat or otherwise use. That's about ownership of an object.

A different, though related concept, is that the first -country- to start using some territory has a claim of sovereignty over that territory. Meaning essentially that the area becomes part of that country.

The treaty says that -sovereignty- rules are different in space, no country can claim the moon or another planet as part of their country, by colonizing it. The treaty's Article 2 reads, "Outer space, including the moon and other celestial bodies, is not subject to_national_appropriation_by_claim_of_sovereignty_, by means of use or occupation, or by any other means."

The treaty says that Mars wouldn't become part of the the USA if the US colonized it. It does NOT say that you can't go to Mars, pick up a rock, bring it home, and then own that rock. That's ownership of an object, not sovereignty over territory, and the treaty doesn't prohibit ownership of an object.

Comment what's this goal? vps or dyndns and sftp/scp (Score 1) 94

> How would you go about it?
> Vpn?
> Web hosted ftp?
> Or something else?

What's the purpose, the goal? A $5 vps might be a solution, Google Drive might be. For being just like running an ftp server at home, dyndns solves the dynamic IP problem , sftp simplifies port forwarding and makes it more secure, but doesn't 100% solve the NAT issue. Some sort of vpn, possibly via an ssh port forward, to an external service may be needed if you must accept remote connctions conveniently. I suppose the actual purpose determines the best solution.

Comment Not really, Oscar grouch kinda lied to you (Score 2) 355

Many of th environmentalists who initially spread the fear about nuclear waste decades ago are now coming out in support of nuclear, trying to undo their fud.

They took two facts about two -different- things and implied they were both true of the -same- thing.

Consider a candle, and some gun powder. The gun powder is dangerous precisely because it releases its energy quickly. The candle releases its energy slowly, meaning that it lasts a long time and is safe.

Nuclear radiation is a lot like heat radiation- some materials release it quickly and a lot of energy released quickly is dangerous. Other materials release it very slowly, and are therefore very safe. The ones that release quickly are dangerous- for a short time.

Computers can figure out all kinds of problems, except the things in the world that just don't add up.