Shannon-Hartley says the theoretical maximum data rate for a channel with AWGN is proportional to bandwidth and the log of signal-to-noise ratio. For an off-the-shelf microphone/speaker pair, I think 16 kHz and 80 dB are probably decent guesses. That would give a theoretical maximum data rate of about 425 kb/s. The practical limit is probably much lower.
It may be possible to increase the bandwidth by increasing the sample rate on both ends, but this quickly leaves the realm of consumer audio equipment (and consumer pricing). At some point you'd exceed the reasonable frequency responses for each device, as well as the medium. I imagine that air attenuates ultrasonic frequencies more than lower ones, but that's just a guess.
I think they only care about preventing data flow in one direction while still allowing it in the other. This isn't strictly an air gap, but it fits their use of the term "data diode". The fact that the unidirectional flow of information is achieved through galvanic isolation is probably just a side effect. In the ideal case, no information can flow from the photosensitive element to the LED. A determined attacker could probably exploit lots of side channels here, though.
> 25 years ago it seemed like physics was mostly complete, and the only remaining work was exploring the corner cases and polishing out all the imperfections. It doesn't feel that way anymore!
Physicists thought the same thing c. 1900, but then one of the "corner cases" turned into the ultraviolet catastrophe[1]. The consequences of the solution to that problem kept the whole field busy for a good part of the 20th century.
I'm highly skeptical of the idea that physics is anywhere near complete. The relative success of our technology gives us the illusory impression that we're almost done, but it's not obvious that physics even has a single, complete description that we can describe. We assume it does for convenience, in the same way that we assume the laws are constant everywhere in spacetime. I view this as both exciting and terrifying, but mostly exciting.
Writing code _has_ helped me feel better on some bad days. Even looking back at old projects brings me contentment and reassurance sometimes. On its own, it can't provide the happiness that a balanced life can, but craft and achievement are definitely pleasing. I would consider it an essential part of a good life, regardless of what the actual activity is.
This is different from meaningless work that brings you nothing except a paycheck, which I agree is important to minimize or eliminate. We should apply machines to this kind of work as much as we can, except in cases where the work itself doesn't need to exist.
My wife is also T1 diabetic. In principle, yes, a major airport's medical team should have everything that a diabetic needs to survive. However, depending on the person's blood sugar level at any given moment, it may be necessary to give them either insulin or sugar immediately or they will become disoriented, unable to move reliably, and maybe pass out. Hypoglycemia and hyperglycemia can quickly become medical emergencies. Given all that, it makes sense for a diabetic to be highly protective of their insulin and sugar supplements. In a crash, the medical team is probably going to be pretty busy and might not provide optimal treatment to a diabetic right away.
A "pancreas kit" can fit in a bag small enough to be carried in one hand, so it shouldn't be necessary to hold up an evacuation by carrying something large. As others have mentioned, this is also likely an instinctive reaction, and it's hard to criticize someone for reacting that way in such a stressful situation.
My mother said similar things before her death, and I accepted them with love while privately dismissing them. But since then I've softened a little. I still don't believe in those ideas in a literal, empirical sense, but they have emotional value for me anyway.
I guess I'm trying to say that, at least for me, it's been more pleasant to entertain these ideas as comforting fantasy, and I don't think that small personal allowance has eroded my more practical abilities elsewhere. Not struggling so much against this kind of thinking has freed me in a certain way.
This blog post[1] may interest you. As you suggested, the workflow seems to be:
1. Try various techniques that might trick the firewalls on both ends to let the connection through. This requires a relay for the initial negotiation only.
>you can get a sport pilots license in as little as 20 hours of training
This is not enough training to operate safely, in my opinion. Even in VFR conditions, I think it would be negligent for an instructor to turn a 20-hour pilot loose without further oversight. Even if a student pilot has flown solo by that point in their training, their instructor still needs to sign off on all cross-country flights. Entering Class B with 20 hours is out of the question in my view.
I also disagree that the Sport license meaningfully decreases the cost of general aviation. The largest expenses are fuel and aircraft rental fees or maintenance, neither of which are mitigated in the long term by a shorter training period.
It sounds like you are probably more experienced than I am, so maybe I'm wrong.
I think this means that a previous iteration of this effort had a value of £249,000. The article is mainly about the current iteration, which has some other total value that is presumably larger. It isn't clear how much the current iteration is worth, at least from the article alone.
In general I agree that this might not be significant, unless the total value of the current contract is large or there are notable research or engineering results.
Specifically, this new stage of the project has £2.9 million of new funding, according to the linked press release. Still feels like pocket change, I wonder how much they can really do with that little
Edit: Here's the config I use to twitter -> nitter
Redirect: https://twitter.com/\*
to: https://nitter.net/$1
Hint: Any word after twitter.com leads to nitter
Example:https://twitter.com/some-username → https://nitter.net/some-username
Applies to: Main window (address bar), IFrames
That got me wondering what other frontends there are for popular sites, and though I don't use reddit, I know a lot of folks do, so this should work for a thing I just found called 'teddit' which is inspired by Nitter
Redirect: https://reddit.com/*
to: https://teddit.net/$1
Hint: Any word after reddit.com leads to teddit
Example: https://reddit.com/u/some-username → https://teddit.net/u/some-username
Applies to: Main window (address bar), IFrames
It may be possible to increase the bandwidth by increasing the sample rate on both ends, but this quickly leaves the realm of consumer audio equipment (and consumer pricing). At some point you'd exceed the reasonable frequency responses for each device, as well as the medium. I imagine that air attenuates ultrasonic frequencies more than lower ones, but that's just a guess.
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