* Posts by Charles 9

16605 publicly visible posts • joined 10 Jun 2009

Robot solves Rubik's Cubes in 637 milliseconds

Charles 9

Re: As for that time...

"Interestingly the computation time is not included for human solvers - they get to examine the cube beforehand, and work out what they are going to do. So the 4.9 second record is simply for executing a series of pre-worked-out moves, with a few (very short) calibration stops along the route."

Which raises the possibility of a variant of the speed solve competition: from a blind start, thus taking into account on-the-spot mental solving as well as the mechanical manipulation into the time.

Charles 9

Re: As for that time...

"Has anyone learned if finding the optimal solution to any Rubik's cube is considered a P or NP problem?"

Found my own answer, though I never knew it as "God's Algorithm". Seems an optimal solution algorithm was written in 1997, and the Cube has been exhaustively studied. But then, I have to wonder why the record breaker took 21 moves instead of 20? Was it for reasons of mechanical efficiency (easier to do certain turns in sequence than others)?

Charles 9

Re: How complex is that problem anyhow?

It's mostly a matter of twisting the cube. It takes a tiny fraction to assess the cube and probably a touch more to determine a solution based on it. Still, the time is quick due to using a low-friction cube. Given its flimsier construction and looser tolerances, we can't expect the same results from the standard cube.

Charles 9

Re: Next challenge: Rubik's Magic

The Magic just isn't as fun. There's a set solution to each one, so fast solvers can do it in a second or so. At least with the Cube, the configuration can be randomized to keep things interesting.

Charles 9

Re: As for that time...

Ah, but they used a special low-friction cube, not the bog-standard cube humans have to solve. I'd love to know what's the fastest solving time, from first glance, using the standard cube. Also, the solution is substandard because it made 21 moves when any cube can be solved in 20 or less. So there's still room to improve.

Has anyone learned if finding the optimal solution to any Rubik's cube is considered a P or NP problem?

PS. I can't see the video due to my blockers.

Charles 9

Re: You know who you were.

Just to be straight, you did this to make it impossible to solve (you can also do this by flipping an edge piece)? A similar trick makes the sliding puzzle impossible to solve (switch two adjacent pieces).

Charles 9
Alert

As for that time...

Is this the COMPLETE time needed to solve the cube, complete with mechanical action? Given the sheep physical distance 20 moves would take, I would call that one heck of a feat.

Which means I don't think so. Probably just the time needed to construct an efficient solution while the actual motors take it nice and easy so as not to break the cube through overexertion.

Chirp! Let's hear it for data over audio

Charles 9

Re: WiFi pairing

Which is good because proper protocol should demand you be right next to the bloody thing when trying this. A cheap but short-range protocol that nonetheless is tough to get through walls (quick chirps will be hard to record through the attenuation of your average wall) would be a good thing.

But then again, why not a QR code, which is silent and also requires immediate physical presence to use?

Trump's torture support could mean the end of GCHQ-NSA relationship

Charles 9

Re: Torture works?

"As the CIA Torture Manual points out, you don't torture the person you want information from. You torture their wife or children within earshot."

Trouble is, what if the man involved has no family (they're all dead) or they've had a falling out and thus hate their family, meaning the torture appeases them? Plus you could end up with a masochist who gets off on torture.

Charles 9

Re: Re Big John

Or betrayal of the Electors...

IPv4 is OVER. Really. So quit relying on it in new protocols, sheesh

Charles 9

Re: IPv6 is OVER!

"But no-one has had to buy a new phone to use it, the complications are handled transparently by the networks."

Because telephones are pretty dumb devices. All the smarts are done by the exchange. However, IPv4 devices can't do that. There's a certain minimum degree of complexity involved. And one of the catches is that IPv4 devices expect a 32-bit address, period.

Charles 9

Re: IPv6 is OVER!

"Yes, all that endless row of people who ended up having to try to explain voltage and current using liquid flow analogies to an audience who's eyes immediately glazed over on any attempt to explain the subject directly must all have been ignorant on the matter themselves. Definitely. Yeah, that must be it."

IOW, YOU try explaining electricity to people who can't understand why 10mA (or whatever current you can get from a handheld stunner) can shock them off their feet.

Charles 9

Re: Granny factor

Because it's the engineers who are most likely to actually be fiddling with these numbers. Thanks to things like DNS and DHCP, why would Granny need to even know these numbers exist? If something goes wrong with their Internet, Granny's likely to call the grandson or some tech who would grok this stuff anyway.

In other words, for most people, IP numbers is Somebody Else's Problem.

Charles 9

Re: IPv6 is OVER!

"So add an extended header at the start of the data packet, put the extra address bits somewhere in that, and define some special SRC/DST values for the existing fields that say 'this is an extended v4 packet'."

Which does NOTHING for the "old device talking to a new device" problem, which IPv6 also has. No IPV4-only device can talk to anything outside the scope of IPv4 without a proxy. It doesn't matter whether it's IPv6, your idea, IPX, or whatever. IPv4-only devices can ONLY see IPv4 devices, and this cannot be solved in the scope of IPv4 alone. So again, if you have to break, why not break clean?

Charles 9

Re: Where I am working right now

So you just keep a couple backup numbers for when you need it, like:

(Google)

2001:4860:4860::8888

2001:4860:4860::8844

(OpenDNS Sandbox)

2620:0:ccc::2

2620:0:ccd::2

(Verisign)

2620:74:1b::1:1

2620:74:1c::2:2

Note that thanks to IPv6 address shortening, these addresses aren't really all that long. The Google ones are even all-numeric and only 16 digits total: not much more than the 12 you may end up using with IPv4. Even if you can't keep these in your head, a quick scribble on a piece of paper slipped into your wallet or phone makes for a handy note in case you need it.

See, IPv6 does try to accommodate. And as for keeping the local DNS address for when you need, don't they keep the notes handy by the access terminal? I figured anyone who's had to configure the DNS and so on would keep a hard copy nearby.

Charles 9

Re: IPv6 is OVER!

And keeping in mind adding just ONE bit breaks IPv4 compatibility. Completely. Period. Because the IPv4 stacks expects 32-bit addresses. Not 31 or less, not 33 or more, 32. It's hard-coded into the spec and can't be changed or extended.

IOW, the ONLY way to add more addresses is to break the mold. If we're going to break the mold, why not start from scratch with some future-proofing in the process. We're using 128 bits (1) so we can keep logical down-the-bits routing that keeps routing tables small and keeps routers from choking, and (2) to help keep the IPv4 exhaustion problem from happening again down the line as unexpected things (like, oh, more and more people starting to connect EVERYTHING to the Internet like what's happening RIGHT NOW) take up more IP space. It's the same reason ZFS uses 128-bit provisioning even if it could probably get away with 96 or maybe even 64 bits.

Charles 9

Re: IPv4 and IPv6

Another reason for IPv6's structure was to deal with routing table problems. Thanks to all the IPv4 address hawking, there's no longer any logical, down-the-bits progression of topology. That's the reason IPv4 routing tables have gotten so huge: to the point some routers choke at the size. The massive overprovisioning of IPv6 is intended to stem a repeat of this for as long as possible, much like how ZFS's filesystem provisioning is intended to make sure physical limits hit before the logical limits do.

Charles 9

Re: Meanwhile

"Such as ?"

Legacy kit that's still being used, still making money, and replacing it is simply not an option. Perhaps it's custom kit meaning replacing it is super-expensive and not guaranteed to work.

How does IPv6 deal with IPv4-single-stacked legacy kit that simply will not go away. Basically, they're STUCK on IPv4 for good or ill. IPv6 is not an option because their legacy kit cannot be upgraded or replaced. This represents a noticeable chunk of the Internet, and IPv6 threatens to leave them behind.

Oh, BTW, Walmart still sells VHS tapes because some people are really, REALLY incapable of understanding ANYTHING newer. Even DVD recorders (the closest analogues) confuse them. They want their VCRs, thank you very much. They'll raid secondhand stores to keep using VCRs, and they'll die before giving them up.

Charles 9

Re: Consumer routers?

It should've. I've had several routers over the last few years that could take an IPv6 address if offered. My current Netgear one, a couple years old, is certainly IPv6-ready and said so on the box.

Toblerone's Brexit trim should be applied to bloatware

Charles 9

Re: Major Bloat

"Dropbox. HTH, HAND."

Offline. Cloud not an option.

Charles 9

Re: Mars

If it's so bad, why do people eat so much of it? And don't say people don't know better because there are plenty of alternative chocolates out there that few seem to buy.

Charles 9

That's what someone else mentioned. There may be a lot of features, and the average user may use only a few of them, but those specific features differ from user to user, to the point that cutting ANY feature results in complaints from those users who actually use it.

Many apps try to be the jack of all trades in order to get the widest audience. Who cares if it's master of none, as long as they get the customers' money.

Charles 9

Re: Mars

At least they still MAKE them. The nickel Hershey bar disappeared nearly 50 years ago. They're not really to blame as inflation raises ALL prices: including the costs of the raw goods needed to make your Mars bar. The same for less or more for the same, you lose either way, and there's little to be done to prevent this.

Charles 9

Re: Just bring me back setups where I can choose what to install...

You've been outvoted. Joe Stupid can't understand your type of setup, he pays as much as you, and they outvote you. You lose.

Charles 9

Re: Windows

"Instead of gold plating and adding features, reduce bugs, inconstancies and vulnerabilities. Write NEW kinds of software instead of version 15 of Word or 12 of Windows."

Like WHAT? Just what kinds of software do we need that people are willing to buy that doesn't exist yet? Ever thought that people buy Word and Office and the like because they actually USE it? As in everyday?

IoT worm can hack Philips Hue lightbulbs, spread across cities

Charles 9

Re: Eh

" though it is possible that infecting just one would be enough."

The critical mass measure is the amount such that an initial infection would likely be able to spread completely through the population because each device has enough neighbors to prevent isolation.

Charles 9

Re: Tinfoil wallpaper time

Tell me, is it effective even in a room with glass windows that are normally radio-permissive?

Charles 9

Re: Hands up who is still a fan of IoT?

Even if you disconnect YOUR WiFi, what's to stop someone else setting up one from outside your premises that your devices can nonetheless reach, and indeed they may be able or even REQUIRED to do so as a Whispernet, which you'd have no ability to turn off unless you'd like to live TEMPEST-style with no windows.

Charles 9

Re: ANY i.o.t

Take it to the logical conclusion; the entire INTERNET is hopelessly flawed and must be replaced. Any ideas?

What do you give a bear that wants to fork SSL? Whatever it wants!

Charles 9

Re: 20K+ 25K

Lighter on resources, maybe, but what about computational power. A 68000 is a far cry from say a modern ARMv7.

Good luck securing 'things' when users assume 'stuff just works'

Charles 9

Re: Who bears the losses ?

"More effective if you replace the normal audio with a track that plays someone screaming.. Young woman is best for effect."

No, because then you'll just deaden people to screaming. It's like with car alarms. They're loud and annoying by design (for the same reason, to draw attention to it), but because of all the false alarms, people start ignoring them. Trip a bunch of false scream alarms, and you'll end up with a case of Cry Wolf Syndrome; people will stop turning up when genuine screams are heard.

Basically, ANY notification system in the world can be trolled to produce Cry Wolf Syndrome.

Charles 9

Re: Not far enough

That's been the catch. Once something has been broken into ONCE, the technique used to break in can be re-tuned as needed to evolve to cover variants. It's a difference in degree but not in kind. It's like how once the Java sandbox was broken, most any sandbox can be easily broken now. It's only a matter of time before the same thing happens to VMs. Plus the human angle is always available. After all, locks can't do much if someone manages to copy the keys.

SpamTorte botnet gets turbo-charged

Charles 9

Re: Major nuisance

They're actually getting pretty clever at getting around filters, or at least gaming them to the point you risk false positives and losing a legitimate e-mail in the process.

Adblock overlord to Zuckerberg: Lay down your weapons and surrender

Charles 9

Re: Do Site Owners Ever View Their Own Pages?

"Do Site Owners Ever View Their Own Pages?"

Yes, and they don't care. Don't forget there are masochists out there.

Charles 9

Re: The ultimate ad-blocker

"Security issues wouldn't be a factor unless you have an exploitable /dev/null. Bandwidth, set a maximum size - accept the first K or so and then break the connection. If the advertising agency has any wit they'll count that as the full advert sent and bill the client accordingly."

But what if the client CHALLENGES the claim and uses their own data to prove it?

Charles 9

Re: How ads work

So what do you do when EVERY home insurer gets in your face? Go without?

Charles 9

Re: Once around again on the same merry-go-round

They'll just make rubber ads. Smack them down, they'll bounce back and smack you instead. Ad people are ingenious. They'll come up with ways to make you see their ads no matter how much you try. That's why ad walls are appearing. Soon they'll probably develop inline ad proxies so that you can't filter the ad without filtering the content as well. Then it'll be all over the Internet. What'll you do after that? Abandon the Internet and go back to the Sears catalog?

Charles 9

Re: Simple solution...

No, because the client can demand PROOF, and they can obtain this for themselves by making test runs. Remember, this is a business contract, and fraud is BOTH a civil AND criminal offense (meaning not only can you be sued for the ill-gotten gains but you can also get thrown in prison for it).

Anti-ultrasound tech aims to foil the dog-whistle marketeers

Charles 9

Re: Keep doing what you're doing

So how do you find the source without an ad of some sort, especially if they're not listed in the phone book (which I don't have anyway)?

Browsers nix add-on after Web of Trust is caught selling users' browsing histories

Charles 9

"As several others have already said, WoT is a very flawed concept,"

Well, can you think of anything better? Because from where I sit, if WoT doesn't work, then NOTHING works because EVERYTHING here relies to some degree on trust that can all-too-easily be betrayed.

Charles 9

And why should we trust McAfee to get it right.

In fact, why should we trust ANYONE?

British firm to build world's first offshore automated ship

Charles 9

Re: motovation

The catch being that there isn't a whole lot of potential chaos factors in space. Same with aviation. Once aloft, airplanes don't have so many chaos factors to consider: turbulence and rogue aircraft, maybe, but not much else. Once you get to sea/ground level, the chaos factors increase considerably: terrestrial and aquatic life, unpredictable motions and waves (thus why we have rogue waves), not to mention the human factor. Put it this way: navigating at sea involves a certain amount of necessary complexity to account for uncertainties at sea such as currents and drift.

PS. And yes, intuition (or rather, subconscious or reflexive knowledge) does play a factor in various mental functions regarding detection and avoidance. These kinds of things we can't teach to AIs because we don't ourselves know how we do it.

In assault on American values, Lockheed blasts pickup with raygun

Charles 9

Re: Just add multiple projectiles to the vehicle to take out the self-illuminating laser.

Unless the laser itself is mobile. Then you have moving target versus moving target, and the laser has the advantage of attack speed such that you don't really have to lead the target to hit it unlike with projectiles.

Charles 9

Re: corner reflector

The rated capacity is based on the materials used to make the reflector. As for right materials, name something that can withstand a sustained high-intensity beam without being too bulky or heavy to be practical?

World-leading heart hospital 'very, very lucky' to dodge ransomware hit

Charles 9
Devil

Re: Of course

Wouldn't matter anyway. Someone will come along and retort, "Don't affect me. I'm heartless."

Charles 9

Re: Old technology called permissions

Ever heard of privilege escalation? Privileges are nothing to one who can SET them.

Charles 9

Re: Okay, somebody tell me why Internet access is not properly locked down

Until a HYPERVISOR attack comes along. They make jailbreak and sandbox escapes. A VM escape can't be fat behind.

Charles 9

Re: "One of our key weaknesses is our people and user behaviour,"

And then they got introduced at communal points where attribution couldn't be assured.

Charles 9

Re: Bleedin' obvious

Or worse, someone on the board...

Charles 9

Re: Luck?

It also meant the backup itself didn't get corrupted: something you have to watch with cryptoware.