Posts by Nigel 11

Re: Not a meterorite

It's literally boiling the water in the atmosphere as it comes in.

A masterly understatement. It's literally boiling the iron or whatever that it's made of. It's probably going past that, all the way to plasma. Afterwards, the iron, silicon, whatever condenses (as oxide, mostly) and hence the thick trail.

If you watch the car footage you can actually see the trail appearing to burn for a few seconds. I expect that's a Nitrogen - Oxygen fire, or possibly or additionally an Oxygen - Iron fire if the meteor was iron.

One of the worries prior to testing the first nuclear bomb was that it would ignite an (exothermic) Oxygen - Nitrogen combustion, that some thought might propagate to consume the Earth's entire atmosphere and everything living therein. I wonder if someone else pointed out that were that possible, a meteor strike would have done it long ago? Or did they just chance it?

Re: How 'sensitive'? Not very.

Much better if society can be persuaded to mount an "immune response" BEFORE the next outbreak of ethnic cleansing, rather than after.

A lesson from history. In the late 19th century the unified state of Germany was formed to great public acclaim. Its new citizens queued up to obtain their papers. The form they filled in was quite simple. One of the questions was "Religion" to which many happily replied "Jewish". After all, this new state had for the first time granted them constitutional protection against harassment and discrimination.

Scroll forwards to the late 1930s and their parents' replies stored in dusty filing cabinets doomed not just the parents, but children and grandchildren not even born at the time.

Re: There's the Kool-aid...

people like me will get sick of trying to retrain them and just go with linux instead.

There's also Linux-lite, aka OpenOffice / LibreOffice running on a Windows PC. It's probably easier to re-train someone off Office 2003 onto OpenOffice, than it is to re-train them onto Office 2007. And the OO folks seem mercifully free of the desire to inflict new interfaces on their users in order to look cool.

And of course the price of OO / LO is very competitive indeed.

Ooh err missus

Blow? Hole? Continu??!!!!!!!!

Re: We should be told...

No, the day after they turn it up to full, they should announce that they accidentally destroyed the universe last night, but nobody apart from a few particle physicists actually noticed.

Re: no disincentive

For some criminals, especially the violent ones, you are right. Some aren't deterred. Their crime doesn't make any economic sense in the first place. But I'm fairly sure that most of those who steal for a living consider their personal risk-reward ratio. Upside: ££££. Downside: self-assessed cost of punishment times chance of being caught. Commit crime if upside > downside. Especially so for those whose crime is planned rather than impulsive.

Crimes against infrastructure cost society a large multiple of the gain to the criminal, and the sentence should therefore be disproportionately heavy. The criminals won't suddenly go straight. But they will go back to the sort of crime where the gain to the criminal approximately equals the loss to the victim or his insurer. In other words they'd stop nicking cable, and go back to nicking cars or breaking into banks, and society at large would be better-off.

Re: I would like

For warrantied quality, buy enterprise-grade drives. They do cost about twice as much as bog-standard desktop ones, though. Personally I'd much prefer two drives mirrored - one made by WD and the other by Seagate, so as to minimize the chance of both coming from the same defective batch. But that's not an option in a laptop.

Re: SciFi Toasts BRAIN

I don't know the details of AES etc, but it's a much greater class of problems than just asymmetric crypto-breaking that could in theory be tackled by a quantum computer.

Basically, N qubits can represent all numbers from 0 to 2^N-1 at once!. You then perform a series of operations on those qubits that if performed on a single number, would tell you (yes or no) that it was a member of the set of solutions smaller than 2^N-1 of your problem. For asymmetric cryptography, that search is for one of two large prime factors. You then observe your system in the quantum sense. It must collapse into one of the possible solutions of your problem - one of the two prime factors, which is all you need to break a code. For other problems there might be a known or unknown number of solutions larger than two, but provided the number of solutions is smallish, repeated runs of your quantum computer would statistically guarantee you'd find all of them ... even if knowing just one isn't all you need to get the rest conventionally.

As the number N of coupled qubits becomes large, quantum computing becomes exponentially closer to magic. That, or we discover a reason why it stops working when N is bigger than some new-physics-determined number.

The observable universe contains something of the order of (only!) 2^84 hadrons. This is why I find it inconcievable that a quantum computer could work with N qubits in the hundreds or thousands, let alone all the way up to millions, trillions and beyond. (Avogadro's number is ~10^26! )

Greg Egan writes the hardest of hard SF. For one possible implication of a working quantum computer for large N, read "Luminous"!

Re: 1TB? no problem!

Something wrong with that heat calculation.

1Pb = 360 (say) 3Tb drives. Power consumption of WD 3Tb "Red" active read/write = 4.4W. http://www.storagereview.com/western_digital_red_nas_hard_drive_review_wd30efrx . 360 x 4.4 = 1584W. You can run that off a single 13A domestic outlet, even allowing for PSU inefficiency and all the cooling fans.

You WILL have to make sure your domestic Petabyte server does a phased disk spin-up, because the power demand of a disk drive while it's spinning up is usually about 20W for about ten seconds. 360 x 20W is 7.2kW, about the same as a somewhat weak electric shower unit, so you'd just have to spread the load over two domestic circuits and four 13A plugs if you weren't sure it would never spin up all the drives at once.

BTW those WD Red drives are extraordinarily quiet, so you wouldn't need ear-plugs provided you could find some enclosures that used big 12cm fans, rather than huge numbers of 6cm fans.

Re: And yet ...

Because rats beed as fast as rabbits. And rats hide down holes too small for cats. And rats are astonishingly intelligent for smallish rodents. (Some of the rat stories I've heard, there must be significant intelligence overlap with humans. There again, some of the dumb human stories I've heard ...)

Cats do catch rats, but they have to hunt carefully because a rat can seriously injure a cat. So the cat has to be hungry to bother, and the rat species isn't in any danger.

If you want a lot of rats killed quickly, get someone in with ferrets and/or terriers. But a week later, you'll still have rats. Smarter rats.

Re: Full height drives

Why not go to a 10lb bag and go back to full height drives

Because a disk drive is an example of something that works better miniaturized. The smaller the platter, the faster it can spin without disintegrating or distorting. The smaller the arm carrying the head, the less it flexes and vibrates, so the faster the settling time after a seek. Both mean that a 2.5 inch datacentre disk has intrinsically lower latency than a 3.5 inch one.

It's like how a flea can accelerate itself at 300G, whereas it takes a lot less to make a human go squishy.

Also you don't need so much energy to move smaller head assemblies, so the drive generates less vibration to upset its neighbouring drives. With tens or hundreds packed close together, this is yet another advantage. I've heard tell of homebrew servers with four desktiop drives bolted into a single metal cage, that degraded quite atrociously under heavy loads. Those rubber drive-mount grommets in the better full-tower cases are definitely not just for show. They provide vibration isolation between drives.

Vibration is also the reason why a big stack of many tens of platters in a full-height enclosure wouldn't work well, if at all.

I wonder how long before we see the 1.8 inch datacentre drive? The one disadvantage of a smaller drive is smaller capacity, but 1Tb is more than enough in many applications.

Re: Doctors caring & empathetic?

Screw up a bloodwork culture and/or misdiagnose something serious, and you can start (fail to prevent?) an epidemic which wipes out the human race / kick-starts the zombie apocalypse. Car mechanics don't build nuclear weapons, so they are far less capable of that scale of destruction.

No, you still laven't thought this through, even at the extreme. Suppose those screwed-up brakes are on a vehicle carrying the zombie plague blood samples to the path lab? In any case, it's not usually a doctor doing the path lab work that can distinguish the merely individually lethal cases from the imminent global pandemic cases. Certainly it won't be a surgeon.

As others have pointed out, cool and detached may be necessary for a surgeon because (a) he can't afford to get emotional while things are going badly for the patient and (b) sooner or later he will make a mistake that causes a death, and if he's too empathetic that's the end of his career. Highly empathetic doctors will go into other branches of medicine. General practice for example, or geriatric care, or psychiatry.

in fact thinking about it, a surgeon is very close to an engineer working on a human body. He needs to be a self-motivated perfectionist. He dosen't need to be empathetic, in fact it may be a handicap if he is.