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Comment: Re: Most unlikely technology in 1981: Handheld GPS (Score 1) 276

always thought the most unlikely technological development in my lifetime was the handheld GPS device. It would be "most unlikely" because it required tremendous, simultaneous, and largely unforeseen advances in several different technologies, each of which was hard to predict in 1981. The list is at least:

1. Low power, low voltage, low noise L-band receivers, sensitive enough to be compatible with the weak signal coming from the internal antenna of a handheld device;
2. Stupendous amounts of digital signal processing, also at low power and low voltage;
3. Digital map databases of (substantially) every road in the world, accurate to a few meters;
4. A substantially world-wide, wideband wireless data link to get the digital map into the handheld device in the first place;
5. Low power, low voltage, high resolution, multicolor flat panel displays;
6. Gigabytes of low power, low voltage data storage memory; and
7. High energy density, high power density batteries capable of supplying the whole thing.

And, perhaps most impressive of all, the manufacturing technology to make all of the above small enough to fit in a handheld device, at a price low enough to sell by the zillions.

Of the list above, probably only #2 could have been predicted, and then only if one were willing to extrapolate the then-relatively-new Moore's Law by a very large amount. (Recall that Mead and Conway had only written their Introduction to VLSI systems the previous year; until then it was not clear that such complex chips could even be designed on human time scales, let alone built for a profit.)

The fact that a handheld GPS device is now an anachronism, since the technology is now small enough and low-power enough to be integrated into other handheld devices, like smart phones, pleases me no end.

Add to that list an item 0:
That a satellite cluster deigned, paid for, and deployed for military use would be freely available for civilian use. (President Regan's decision to allow that, in the wake of the Korean Air flight 007 wasn't made until 1983 and the satellites weren't launched until 1989).

Without the military necessity and funding behind it there's basically no chance that the GPS satellites would have been deployed, and without Regan's decision there's no reason they would necessarily have supported unencrypted civilian use.

But yeah, I like your unlikely technology prediction. Although certainly much less capable handheld GPS units existed long before the map based raod navigation one's you were primarily referring to.

Comment: Re:Germany lost the BoB because of Hitler's stupid (Score 1) 353

it would still have the option of training new pilots in Canada

Which they were already doing (Which you probably knew or you wouldn't have mentioned it.)

Yes. I should have used "ability to train", or "ability to continue to train", instead of "option of training".

I did know they did flight training in Canada, and didn't mean to imply otherwise.

Comment: Re:Germany lost the BoB because of Hitler's stupid (Score 2) 353

The Germans lost the battle for many reasons. They were losing aircraft fast, not just in combat but due to maintenance needed. Planes have to be pulled out of the line and refurbished every so often. They can't fight forever. Unknown to the Germans, the British were far out producing them in fighter aircraft. Almost double the production. The problem the British faced was a lack of pilots to man those aircraft, and a degradation of the support infrastructure. Same as pilots, the ground crew, maintenance and airfield engineers were wearing out. But, so were the German ones. It turned into a battle of attrition. The Germans were deeper to begin with, but the British were losing less over time. The Germans eventually broke first. Their change in tactics was to cover the wearing out of their air force.

And don't forget the limited range of the German fighters.

The Battle of Britain was more the battle for southeast Britain. Unless RAF Fighter Command cooperated, by staying in a losing fight, there was basically no way for the Luftwaffe to seize and maintain air superiority in support of a seaborne invasion.

The RAF had plenty of bases north or west of the Luftwaffe fighter's effective range; so if the attrition started going too badly against the RAF they had the option of temporarily pulling back to train up additional units, but could still surge forward if / when the invasion began. And Luftwaffe bombers would get shredded trying daylight unescorted raids against those more distant airbases.

Ultimately, as painful as it might have been to people on the ground in that southwest portion of Britain, the Luftwaffe could only inflict a level of attrition that the RAF was willing to accept. It would be quite different if the Luftwaffe had the range to put fighters over any part of the UK, because then the RAF has to come up and fight, or its units get destroyed on the ground by fighter sweeps or escorted tactical bombing missions; though at least it would still have the option of training new pilots in Canada - so it wouldn't be quite as bad off as the Luftwaffe was by the end of the war where there was a good chance a trainee pilot would be shot down by Allied fighters before finishing flight training.

Comment: Re:Wake up SAE. Standardize TREs now. (Score 2) 191

by Jonathan_S (#46260521) Attached to: Elon Musk Says Larger Batteries Might Be On the Way

I like the idea of towable range extenders, but if you're renting one, what are the advantages over automated battery swapping instead?

I can see a couple advantages to towable range extenders.

Probably the biggest one is that once you've rented it you can continue to extend the range indefinitely by utilizing existing widely deployed infrastructure (stopping at a gas station to top up the generator's tank). So you can use to for trips into areas where the charging or battery swap stations haven't reached yet.

It also sidesteps the issue or concern about people swapping out, or receiving, an old reduced effective capacity battery pack at a swap station.

And the rental place needs less infrastructure than a battery swap place. To do battery swap you need the tools (or automated machines) and access to pull the existing pack and install a new one. For a towable rental you barely need more than an empty lot to park them until they've been rented.

And when a battery swap place gets a battery back they need a pretty hefty electrical connection to charge it back up for the next use. The towable rental place needs a gas can (or to take the returned genset by a gas station to top it up); plus they could use the rental car style gas fees to encourage people to return the range extender with a full tank - no practical way to do the same for battery swap.

Comment: Re:The fog of time (Score 1) 160

by Jonathan_S (#45863233) Attached to: Development To Begin Soon On New <em>Star Control</em> Game

You could just wander into the stars, get lost, run out of gas, or fall afoul of an enemy you weren't prepared to defeat, lose the game and have to find a 20-gameplay-hour-old savegame to usefully recover.

You could certainly get taken out by an enemy you couldn't defeat; wander into Ur-Quan space with too slow a main ship, or those damned slylandro probes. (Doesn't do much good to emergency escape if you can't run clear in hyper)

But short of providing a fight with the traders, or in the very near end game (after they fled), it was virtually impossible to permanently run out of gas. The traders always come alone eventually and give you more. I once got bored and pushed it and I think I ran out my ship out of fuel five or six times in a row and they kept showing up like AAA (even if you have no resources or info to trade them you still get gas to get back to Earth)

Comment: Re:Japanese Military (Score 1) 282

by Jonathan_S (#44509419) Attached to: Japan Unveils Largest Warship Since WW2

The new USS America [wikipedia.org] has a flight deck of the same size. France's (only) aircraft carrier is about ten meters longer. The gigantic Nimitz-class supercarriers are the exception to the rule.

Just using flight deck length is misleading.
While the French Charles de Gaulle carrier is only 13 meters longer, it's almost 70% wider and and overall it's twice as big (displacement).

Here's a bit more detailed listing,
name (year launched)
tonnage (standard), length x beam (flight deck)

Izumo (2013)
19,500 tons, 248 x 38 m

HMS Invincible (1980)
22,000 tons, 209 x 36 m

HMS Ark Royal (1955)
36,800 tons, 245 x 52 m

Charles de Gaulle (2001)
37,085 tons, 245 x 52 m

USS America (2012)
45,000 tons, 257 x 32 m

USS Midway (1945)
45,000 tons, 295 x 34 m

HMS Queen Elizabeth (2016, planned)
70,6000 tons, 284 x 70 m

USS Nimitz (1975)
100,000 tons, 332 x 77 m

The Izumo is less than half the displacement of a late-war WWII design, and lacks the flight deck area of more modern carriers (which due to their angled flight deck are substantially wider at the flight deck than at the waterline). Unsurprisingly it's closest to the displacement to the Royal Navy's old through-deck cruisers (aka 'Harrier carriers') which had the similar mission of supporting helicopters for anti-submarine patrol.

Comment: Re:Valet Key (Score 1) 453

by Jonathan_S (#44336913) Attached to: TSA Orders Searches of Valet Parked Car At Airport

Does the valet key somehow negate the manual trunk release? Honest question, as I own a hatchback.

Not automatically, but (most?) cars have a disable switch you can throw to disconnect the trunk release button/lever. It's always behind a lockable area that the valet key can't open - I've seen them in the trunk itself (often a lever on the side of the lock mechanism) or in the glove compartment.

Hit that disconnect, lock the trunk and glove compartment with the normal key and then the valet key won't be able to access the trunk. (My old car you also had to lock the folding rear seats with the normal key; those weren't linked to the trunk release button, so it was more of a pain)

Comment: Re:Harrier? (Score 1) 86

een done. S-72 and X-50 prototypes. Its very unstable. The bring a rotor to a controlled stop thing is easy, existing rotor brakes can be geared to align it fairly precisely when it comes to a stop. The lift transition is the issue. It's not just that lift is basically 0. It's that one half of the rotor disc (the theoretical abstract describing the lift forces) has to completely reverse the airflow of the lifting surface.

Its essentially an expanded case of the Retreating Blade Stall problem.

But the retreating half of the rotor disc has to, as some point, go from generating lift from a retreating motion through the air (moving backwards relative to airframe, due to rotation) to generating lift from an advancing motion through the air (moving forwards, relative to airframem though no longer rotating). The easiest way to think about it isnt to think of it as going from rotating to fixed, but rather think about a rotor that is simply being reversed in direction (simplfies a lot of math).

So at some point in the middle there, half the rotor disc will fall below stall speed, and experience a stall similar to the effect of a Retreating Blade Stall. Worse, won't regain sufficient lift until its now going ~100 KIAS in the opposite direction. Think of it as stalling between -100 and +100 KIAS (example number) as it crosses the transition.

The only craft I can see being able to cross that boundary zone would be a very small, very lightweight rotor that is able to make extremely fast accelerations, and thus cross the zone before it's able to affect the craft much. A full scale craft would simply have too much inertia/momentum to be able to make the transition fast enough, without tearing itself to pieces. Likewise for any craft trying to stop the rotor and use forward motion to generate the lift.

Theoretically couldn't it work if the craft had enough sufficient fixed wings to provide most of the lift necessary for level flight at transition speed?

Then you should be able to trim the rotor disk to near zero lift (beginning a relatively mild decent) before braking it to a stop. Once stopped, retrim it for forward lift and level off.

Mind you those big wings would likely do ugly thing to the airflow in vertical lift mode...

Comment: Re:Security is only as good as its weakest link. (Score 1) 164

by Jonathan_S (#42865497) Attached to: How To Sneak Into the Super Bowl With Social Engineering

"Track performance and give bonuses to the people who manage to stop the intruders."

Ensure the bonus even goes to the average schmo hot-dog vendor who challenges somebody who doesn't have their ID showing. It's not a new strategy, but turning it into a game like this shifts cultures. Suddenly all the con-man defenses of "seriously, don't you know me?", "man, you're uptight, chill." or "Bob says it's okay" fall out the window to your "hey, I get $50 if you don't have a badge".

Not to pick on hot-dog vendors. They're probably more people savvy than most of your security team.

But like implementing bonuses for lines of code written, or number of bugs eliminated, be careful to put in safeguards against people gaming the system.

If all you do to "intruders" is ask them to leave it probably won't be long before someone gets the bright idea to ask a few friends to drop by and try to slip in. Or even for a coworker or two to "forget" their badge in order to split the reward.

Comment: Re:Particle problems, too? (Score 1) 80

by Jonathan_S (#42487929) Attached to: Three-Mile-High Supercomputer Poses Unique Challenges

This is ridiculous. Just pressurize the server room or whole building and be done with it. That layer of air would automagically reappear for the heads to glide over the platters.

Of course that means that the room pressurization would be a single point of failure for every hard drive you had. Lose pressure and every drive suffers a head crash simultaneously... Oops.

If I didn't need the storage volume I'd certainly prefer drives like SSDs that didn't require pressurization to work at that altitude. One less thing to go wrong. (Although the ability to pressurize the building when necessary to make maintenance / upgrades easier on the IT guys would be cool and useful)

Comment: Re:I love the 'privacy' arguments here. (Score 3, Insightful) 297

by Jonathan_S (#42224909) Attached to: Black Boxes In Cars Raise Privacy Concerns

I don't agree, and largely because you don't have a 'right' to drive within the United States, which is likely where they'll draw any legal help for challenges within the US. You also have limited rights in public places. What's the difference between a black box in the car and investigators measuring your travel speed using a camera from a gas station across the street? Or even in the same parking lot?

I'd say about the same difference between unmarked cars following your car around 24/7 and a GPS tracking device.

Yet the Supreme Court unanimously found that there was a significant difference in that scenario; that the later required a warrant (while the former didn't)

Sometime technology makes something so easy or so covert to widely accomplish that it, in practice, makes it effectively a change in kind not just degree. When that happens laws are written, or courts can find, that because something has become far easier to do that additional protections are required to maintain an acceptable level of practical freedom.

Comment: Re:logic for need of an exp. date (Score 1) 584

by Jonathan_S (#41433719) Attached to: Federal Judge Says No Right To Secret Ballot, OKs Barcoded Ballots

Requiring an expiration date on the ID also limits how long the person the ID is legitimately issued to could illegally vote in their old district/state after moving away.

The address on the ID was presumably accurate when issued; but who knows how long it'll remain accurate. Getting a new ID issued with the new address doesn't alter the old ID, and it's not like voting stations are checking any kind of ID revocation list.

Comment: Re:Indie games! (Score 3, Informative) 197

by Jonathan_S (#40692455) Attached to: The Decline of Fiction In Video Games

What I really miss is the X-Com: UFO-style turn based strategies. I know there are some of the replicas (sort of) out there, but none of them even approaches the "X-Com: UFO Defence" in terms of gameplay. X-Com: Apocalypse was nice upgrade of the graphics and even had some gameplay improvements, but after that all sequels and clones kinda lost the point.

Were you aware that there's a new X-Com: Enemy Unknown game coming out this October from Firaxis (Sid Meyer's company, the ones who make Civilization).

From what I've seen it looks pretty true to the original game's play. As a fan of the first couple X-com games I'm really looking forward to it.

Comment: Will it be practical? (Score 4, Insightful) 142

by Jonathan_S (#40438027) Attached to: "Twisted" OAM Beams Carry 2.5 Terabits Per Second

This is very cool, but the current super high bandwidth demonstration is being done with optical light over very short (1 meter) distances.

The article did point to an article from a couple months ago about the first ever OAM transmission; which was done with radio waves. But the antennas used look very directional and there was no mention of bandwidth.

Optical might be useful to further increase the speed of fibers, and highly directional radio might help for satellite broadcast or to compete with microwave relay towers. But requiring highly directional antennas, on both ends, isn't good for mobile wireless.

Hopefully we'll see another story soon where someone figures out how to detect and transmit OAM encoded radio waves from non-directional antennas.

Comment: Re:Didn't Sony say the same thing at first? (Score 1) 105

by Jonathan_S (#39594439) Attached to: Microsoft: 'Unlikely' Credit Card Details Lifted From Xbox 360s

If someone was claiming they hacked the Xbox/Live network and got access to credit cards, the comparison might be accurate. In this case, they're claiming they got credit card information from a device that doesn't have it.

And even if it did have it, I think there's better ways for bad guys to get credit card numbers then buying an Xbox one at a time, using a modding tool, grepping the filesystem and pulling out numbers.

It also sounds like there's no evidence from the article that the numbers were actually credit card numbers. I know every Discover card starts with 6011, but not all 16 digit numbers that start with 6011 are Discover cards, as an example. You also can't assume that any 16 digit number that starts with a 3, 4, or 5 and ends with a valid check digit is a credit card number.

Very true. And since Microsoft only appears to accept Visa, Mastercard, and AmEx (not Discover) for xbox live makes the chance that the investigators recovered a previous owner's Discover card number even less likely.

Premature optimization is the root of all evil. -- D.E. Knuth

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