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Submission + - Automated uploaded-file verification? 1

VernonNemitz writes: There are a lot of ways for hackers to abuse a web site, but it seems to me that one of them is receiving less attention than it deserves. This is the simple uploading of a malware file, that has an innocent file-name extension. I'm looking for a simple file-type verification program that the site could automatically run, on each uploaded file, to test it to see if it is actually the type of file that its file-name extension claims it is. That way, if it ever gets double-clicked, we can be assured it won't hijack the system or worse. At the moment I'm only interested in testing .png files, but I'm sure plenty of web site operators would want to be able to test other file types. A quick Googling indicates the existence of a validator project under the OWASP umbrella, but is it the best choice, and what other choices are there?

Comment Re:Well duh (Score 1) 294

"possibly be compatible with the US Constitution" --The fundamental problem is that the US Constitution does not define "enemy". It defines "treason" in terms of "enemy", but it doesn't define "enemy". At this time Congress or the President has to officially declare some entity to be an enemy of the US, for the concept of "treason" to apply. It is not enough for that entity to declare the US to be an enemy --such a declaration is not automatically reciprocated. But perhaps it should be. Yet, even if it did, we can recognize that the concept of "enemy" has flavors. The lead article uses the phrase "Beijing's political enemies", which is a different thing than a "you must be destroyed" sort of enemy. Which still doesn't help, with respect to the US Constitution.

Comment Re:There must have been fuel on Moon... (Score 4, Interesting) 151

While the lead comment of this particular thread is funny, there actually is fuel on the Moon, in the form of oxygen in rocks, and hydrogen from the Solar Wind. There is also plenty of solar energy available, for cracking oxygen loose from the rocks, and for collecting/concentrating the hydrogen. Let us imagine a Moon-girdling system of solar power collectors and hydrogen collectors, plus power transmission lines so a single large oxygen-extraction plant can operate continuously even when it is night on the Moon.
NOW imagine we aren't the only species in the Universe that does something like that. If they use Alternating Current in those power-transmission lines, then we could put radio telescopes on the Moon and detect radio waves of the AC-power frequency from distant civilizations. (Can't detect any AC from a home-world that has an ionosphere; can only detect AC from airless worlds.) If they use Superconducted Direct Current, we are out of luck with respect to detecting them. Note AC could be cheaper than SDC, but SDC will be more energy-efficient --yet stellar energy is "free" after the capital cost of infrastructure, so some alien civs might use AC and others might use SDC (and I have no idea which we might use, unless we decided to be paranoid and use SDC to be less detectable).

Comment Negativity and the Subconscious (Score 2) 247

The old motto "Don't be evil" has always bothered me because the phrasing encompasses two negative things. It is my understanding that the subconscious mind tends to ignore words like "don't", and only focus on the rest of any statement that includes it --which in this case would be a statement that is still a negative thing! So, the new motto "Do the right thing" is, in my view, a vast improvement over the old one. Sure, the subphrase "right thing" is open to interpretation, and we can be sure that sometime someone will choose a problematic interpretation, but for the most part it is quite a positive motto.

Comment A gap not normally considered (Score 1) 92

Each memory address is normally associated with 8 bits of data (not counting correction bits). But processors nowadays routinely consume 64 bits at a time. That means getting the data from 8 different addresses simultaneously. Things would be simpler if they put all those 64 bits at one address --if every single address had 64 bits of data associated with it. In the previous processor generation, gobbling 32 bits at a time meant accessing 4 different addresses simultaneously, and the total accessible address space of the processor was essentially 30 bits instead of 32 bits --while you were allowed to access 4 addresses starting at Address Zero, you were not allowed to access 4 addresses starting at Address One or Address Two or Address Three. It could have been allowed if every address had had 32 data-bits associated with it. With 64-bit processors today needing to access 8 addresses at a time, the total effective address space is 61 bits instead of 64 bits (still a huge number, I know). Anyway, my main reason for writing this is, wouldn't memory run slightly faster if it didn't have to access all the data from 8 addresses simultaneously, but instead just got 64 bits, nicely parallel from any one address?

Comment Re: Nostalgia is nice (Score 2) 124

Nostalgia is nice, but "retro" can accommodate it in a modern way. Like putting more efficient engines in a lighter-weight (composite fiber construction) look-alike, of the original Concorde. Building a modern look-alike might cost less (3D manufacturing for special parts) and be safer, too (no years of age and wear-and-tear on a new plane).

Comment Re:Evidence of error? (Score 1) 365

I think you are not noticing a fundamental point of physics. But before getting to that, a separate point needs to be addressed first. The Type III civilization uses the energy of its galaxy; it doesn't have to generate that much extra energy. Just like a Type II uses all the energy of its star; it doesn't need to be generating the equivalent of a star. One way to make a Type III is by filling a galaxy with Dyson Spheres. So, the only way to see that galaxy at all (besides stars not yet englobed) should be in the infrared or lower, not the visible/higher frequencies.
Now the physics point: Like extracting energy from a waterfall, higher-energy stellar photons can be used to do work, and leave the system as lower-energy photons. But the same total energy must leave as arrives. Else the "system" processing that energy-flow will get hotter and Type II or Type III civilization would overlook such an important thing, in creating Dyson Spheres around stars.

Comment Evidence of error? (Score 1) 365

According to the article linked in the news blurb, "encapsulating the energy of stars by so called Dyson spheres or swarms is one way to harness enormous energies" --the thing that bothers me is, nothing is described about how an advanced civilization using the total output of stars changes the measurable total output of stars. It makes sense to think that light-frequency-and-higher emissions would be reduced, while infrared emissions would be increased --something any appropriately-large dust cloud can do! It seems to me that we should want to analyze visibly dust-free-zones for excess infrared. And radio waves pass fairly well/equally through all dusty and non-dusty zones, which is why radio astronomy is popular, so...what am I missing?

"The most important thing in a man is not what he knows, but what he is." -- Narciso Yepes