Posts by Nigel 11 3191 publicly visible posts • joined 10 Jun 2009
My guess: a spherically symmetrical collapse wouldn't.
Two neutron stars or black holes orbiting each other will eventually merge. They lose energy by gravitational radiation ( and probably by drag induced by infalling gas, etc.), and get closer, which increases the radiation, until there should be a realy intense pulse just as the two stars or holes merge. Bigger, I think, than any single-body collapse could accomplish. (Caveat: "obvious" answers in GR, often aren't)
Awesome indeed.
http://en.wikipedia.org/wiki/Magnetar
A magnetar's 10^10 tesla field, by contrast, has an energy density of 4.0×10^25 J/m3, with an E/c2 mass density >10^4 times that of lead.
remarkable things happen within a magnetic field of magnetar strength. "X-ray photons readily split in two or merge together. The vacuum itself is polarized, becoming strongly birefringent, like a calcite crystal. Atoms are deformed into long cylinders thinner than the quantum-relativistic de Broglie wavelength of an electron." ... At 10^10 teslas, a hydrogen atom becomes a spindle 200 times narrower than its normal diameter.
The magnetic field of a magnetar would be lethal even at a distance of 1000 km due to the strong magnetic field distorting the electron clouds of the subject's constituent atoms, rendering the chemistry of life impossible
Does anyone know what is the maximum magnetic field strength that could exist in even wierder circumstances? Is it where the engergy density of the field would cause collapse of space-time into a black hole, or is there some other limitation?
so Maxwell's equations have the full symmetry that would result from it:
Feel free to write the equations with full symmetry. Then there's a supplementary equation that you use to generate the more useful but less symmetric forms, because as far as we know magnetic monopoles do not exist.
There's actually a proof that in a universe with spherical topology, at least two magnetic monopoles must exist. It's the same as the one that says you can't get all the hairs on a (perfect, seamless) tennis ball to lie parallel to the surface at once. So either the universe has a toroidal or more complex topology, or magnetic monopoles do exist somewhere out there. (Possibly, outside the observable universe, at which point things start to get a bit philosophical. )
I read a paper about giant waves once. (I found that the maths was nearly as heavy as the seas it described). Basically, once sea waves get very large, they cease to behave in line with simple theory, and start to attract each other. This means that the distribution of size of ocean waves has a long (and very dangerous) tail. Where the ocean is shallower than a good few times the height of the wave, things get even worse.
"Freak wave" seems a reasonable term for something that a mariner will see no more than once or twice in a lifetime of seafaring.
400Hz is also MIL spec. It's used on ships and planes because 400Hz motors can be smaller and lighter. It's not used on utility grids becaujse long-distance transmission losses are prohibitively high. 400Hz pre-switched-mode power supplies were also lighter, and needed less huge electrolytic capacitors.
Did CDC sell a lot of kit to the US Military? I'm guessing that they did.
@AC 6th July 09:39 think about the then-acceptable fuel (in)efficiency of a 1968 gas-guzzler, and consider that one can greatly increase the range of any electric car by adding more batteries. However, that's at the expense of performance (more weight) and efficiency (more energy wasted speeding up and slowing down the extra battery mass).
I suspect that the top speed of 50mph had quite a bit to do with the weight of the batteries needed to get that range. A lot of progress HAS since been made. Today an electric car can be competitive on most fronts except range and capital cost, and perhaps the biggest thing holding e-cars back is the lack of a standardised national recharging infrastructure.
Didn't English evolve from a Germanic language anyway? So this is just it coming full circle :-)
In general, no. English is actually a relatively recent new language (compared to Greek, German or French).
It was formed by the amalgamation of the Germanic language spoken by the English Saxons, with the Norman-French spoken by the 1066 invaders. As the communities merged, a creole (technical linguistic term) developed. To see what was happening, get a copy of Chaucer's "Canterbury Tales" that has the original on one side of the fold and a modern English translation on the other. Chaucer was near the start of the process. The Saxon proto-English used by the peasants, and the French proto-English used by the nobles, are still quite different, but coming together (his pilgrims understood each other without translators). It's a good read, by the way. Then watch a play by Shakespeare (who perfected the unified English Language, or maybe even invented it). You shouldn't need any translation.
The process slowed down after Shakespeare, but hasn't stopped. In particular, the grammars of Norman French and Saxon were incompatible, and English has been and is progressively jettisoning its grammar. It is quite possible English will evolve into a pure placement-positional language over the next few centuries (more like Chinese in structure, than anything else of Indo-European origins). The collision between two languages may also be the reason why English has voraciously assimilated words it needed to plug gaps real or imagined in its own vocabulary, from any source, or by neologistic invention. (Is neologistic a word? Do I care? )
Back to "shitstorm", it's no surprise at all that both parts of the word are of Germanic origin. English has preserved a distinction between "polite" words of French (noble) origins, and "rude" ones of Saxon (peasant) origins, which are synonyms or almost so. (e.g. "tempest" vs "storm", "execrement" vs "shit"). Many languages (including, I'm told, Gaelic and Arabic) don't have any rude words, and one has to employ florid combinations if one wishes to offend. "May the fleas of a thousand camels infest your armpits" and suchlike.
Where do German verbs go? It depends whether you're trying to be formal / pompous / incomprehensible or not! Informally, after the subject and before he object, like English. Formally (and almost always so in writing) at the end of the sentence. You can skip ahead with your eyes, but not with your ears.
I too was wondering how a combination of two English words both obviously of common origin to the German, could be called an Anglicism? I'd have expected it to be almost immediately back-translated into German. Or would a native German speaker find that "Shitstorm" trips off the tongue more easily than "Scheissturm"?
I think magnetic storage will hold on at the large data end. When one combines bit-patterned media and heat-assisted recording (BPM and HAMR) one can anticipate drive capacites measured in tens of Terabytes. This is technology that's already working in the lab. I should think that the question at present, is whether anyone will ever want single drives that size? Having Terabyte flash caches up front may well drive demand.
I don't think power consumption is too much of a problem for the forseeable future. An SSD uses something like one watt spread out over maybe 40 square centimeters. (And note, some of that is the controller not the flash chips). A CPU or other highly active logic chip uses maybe 100 watts originating in maybe one square centimeter, but spread out over a heatsink footprint of maybe the same 40 square centimeters. So provided there's good thermal connectivity between stacked chips, one could stack a hundred of them (with a decent heatsink on top) without exceeding the thermal loadings that are commonplace in desktop PC CPUs and high-end graphics cards. (I doubt we'll be seeing 100-deep stacks any time soon, but thermal loading isn't the reason).
Price/Gbyte? Well, it'll be interesting to see just how far and how fast economies of (vast!) scale can drive down the price of manufacturing flash chips.
Presumably Apple buy LEDs from companies in (say) China that aren't paying royalties. If they were buying royalty-paid proucts from (say) Cree, there would be no case.
I'd like to know whether Apple got a cease-and-desist letter some years ago, or not.
But even if not, they're using a patented technology on which royalties have not been paid. I think the way the law works, the aggrieved party sues Apple and Apple can sue their supplier in turn. (Except, the supplier is in China? Well, that's the choice they made).
Do patents apply to personal use?
In the UK, that's a definite no. One of the purposes of the patent system is to place inventions in the public domain, so that everyone else may attempt to create further advances on the technologies so disclosed. To profit thereby you'll have to license the original patent, or await its expiry. Infringement is manufacturing or using a patented device or technology for profit.
In the days before patents existed, inventors kept the methods by which they manufactured things secret, and the method of manufacture often died with its inventor. This was not in the public good.
Not all patents are bad. It's the stretching of patent law into areas for which it was never intended that's bad, along with USA-style law and lawyers. Software should be covered by copyright, not by patent. The imitation of business methiods should be permitted - first-mover advantage should be sufficient reward. And so on.
It's certainly not trolling, if it's a genuine patent on a genuine invention. If Philips, Cree etc. are paying royalties on the patents, that suggests to me that this is the case. (In the case of Cree, that's a royalty on a large percentage of everything they make). These are large companies that are perfectly capable of out-lawyering a university if they feel they have a case (and probably even if they didn't, but I'll assume that they are honorable and/or care about the PR).
The track-ball was probably better, at least until the modern optical mouse (no moving parts) arrived. You can still buy them. They cost a bit more.
For driving a CAD or artistic-design system, track-pads(*) with pens or wands remain commonly in use. Absolute rather than relative position control. Again, better, but definitely a lot more expensive.
The mouse is definitely the best idea if cost is factored in.
(*) not to be confused with the finger-sensing track-pad on a laptop.
I think it probably is a coincidence. I was using computers with mice well before 1987. Back then, the mouse was an inferior but cheaper interface compared to a track-ball. A 2-axis joystick was also sometimes used. Given that the computer cost a 4- or 5-figure sum, the added cost of a track-ball wasn't a particularly noticeable extra and neither would the royalties on a mouse have been. Mice took off when computers got cheap enough that the cost of the interface device became a significant part of the system price.
Mouse evolution: each was perceived as a huge leap forward in quality.
Mk. 1 two wheels scraping on desk. Diagonal motion had a very nonlinear relation to vertical or horizontal motion!
Mk. 2A one ball scraping on desk, driving two wheels inside the mouse. Contact rotation sensing. These mice degraded quite rapidly as the contacts wore out or got dirty.
Mk. 2B as Mk. 2A, but with optical rotation sensing.
Mk. 3, optical mouse with no moving parts, as is universal(?) today. Early versions required the use of a mouse-mat with a particular pattern printed on it. Losing the mat was like losing the mouse!
Youngsters have probably never experienced the joys of trying to get the accumulated fluff and sticky muck off the rollers and wheels in a physical-contact mouse.
I also have another reason for not buying Sony. It's the heap of unrepairable broken-down Sony laptops that was in my office until they recently got carted away as scrap. There's no corresponding heap of broken-down Toshibas or IBMs. Of late, I've been replacing lots of Sony-branded CDRW and DVDRW drives in desktop systems. Not just a single "lemon" model, either. Samsung drives of similar vintages are soldiering on.
Let's not forget the whole 'Pearl Harbour' thing on our trip down Memory Lane...
That's a very silly straw man. If I were convinced that nobody still worked at Sony who bore responsiblity for the betrayals of trust Sony inflicted on us, I'd start considering the purchase of their products again. They might have sacked everyone responsible, all the way up to the board. Most employers call deliberate criminality "gross misconduct". Sony didn't.
It's a personal choice. I'm denying them my money in revenge for the chunk of my life that their rootkit activities wasted (by making my work environment generally less pleasant). I'm glad to see, so are quite a few others.
A suggestion for Angela Merkel. Give Snowdon asylum in Germany. Quote the national-interest exception to any extradition treaties if the USA asks for him. That's how to find out every last detail, and also how to send a very strong signal that we really really are not amused.
Of course, it won't happen.
@AC 15:27. It's not a common philosophy, but one can believe that nothing really exists except one's own thoughts. "Am I a man dreaming I am a butterfly, or a butterfly dreaming it is a man". If you work in IT and are familiar with the concept of virtuality, it's actually a less strange idea than it might be otherwise. How can you prove that you and I are not simulations of human brains, in a historical simulation being run by the beings that supplanted humanity during the technological singularity that has already happened out there in the real solar system.
Occam's razor comes in handy with thoughts like this, but that's an axiom not a proof.
What is the difference in belief in God and belief in No_God? Answer: two letters and an underscore.
The problem is belief, without evidence. In a universe containing very good evidence for its own creation, is it really wise to deny all possibility of a creator just like that? As soon as you start thinking that's OK, you are on as much slippery path to logical inconsistency and moral ruin, as those who assert that the creation was 6000-odd years ago because this book says so.
I'm a militant agnostic, otherwise known as a scientist. Yes, I do have to start with a few axioms (which I'll drop if anyone ever finds a way to disprove them). One is that there exists an objective universe outside my head. Another is that Occam's razor is a really good idea.
wonder if we can set up a country with entry requirements based on a support for the scientific method - a citizen is free to worship any god or gods they please, so long as they can first devise a proper peer-reviewed experiment proving that said god(s) actually exist.
I believe in the universe, but I'm b*****ed if I can think of an experiment that proves it exists. What would the control be? I'm not even sure that I can prove that I exist.
didnt Buddhism produce some of the finest warriors of their time (the Japanese samurai)?
Samurai beliefs had wandered a long way from the source. If they were still Buddhist at all, they were a sect on the fringes. And on the fringes of the fringe, the Japanese suicide-asassin sect, the name of which I've forgotten. Devote your life to learning to kill, kill the man your Abbot ordered you to kill, then kill yourself to attain Nirvana if you survive your mission. Truly bizarre.
Buddhism begat many of the martial arts. The forms of unarmed combat that specialize in redirecting an opponent's attack against himself are probably truest to their source. It is not necessary to become a punchbag to believe in non-violence.
Terminal? Hardly.
What's happening is that the desktop market is both saturated (in the West) and mature. People who need desktops (for business and for serious hobbies) have them already. Why buy a new one? 1. Because the old one has broken down. 2. Is there a two? Windows 8 is a new reason NOT to buy a new one if the old one still works. Ignoring that, desktop sales will go from one every 3-5 years to one every 6-10 years: down to 40% of the boom-time sales, then flat for the forseeable future. That's still a huge market.
The winners from Microsoft's incompetence will be Apple and (maybe) Linux. Also I can't see Windows 8 making much of a dent in iPad and Android tablet sales.
The tablet market will soon enough be mature and saturated. I suspect Tablets aren't replacing desktops, except for home data consumers who only ever had a desktop because it was all they could get at the time. Tablets are mostly supplementing desktops.
I would be interested to know what other "box" you think the OEM's should of been building
That's easy. On the desktop, an iMac-alike that runs Windows and Linux, priced at the usual industry margin rather than Apple's huge mark-ups. (Dell are actually selling something like this - for the first time in ages I was somewhat impressed by a bit of Dell hardware). On the lap-top, what we have but with higher-resolution screens (again, much like Apple hardware). 1360x768 isn't enough pixels on twelve-inch screens, let alone 17-inchers.
Just don't import Apple's hardware (un)reliability!
I also believe there should have been a lot of mileage in a Tablet with a passive docking station (stand plus bluetooth keyboard and mouse), where the interface switched from touch-optimised to desktop-optimised when you "docked" it. That's what Windows 8 might have been: competition for the iPad when un-docked, Windows 7 desktop when docked. That it isn't is Microsoft's fault.
Actually Apple gets desktop computing right - the UI on an iMac has nothing much wrong with it. So Microsoft obviously wasn't aping Apple, when it decided that the world really wanted a mobile phone interface on a 1920x1080 monitor (or two, or four).
Microsoft could let manufacturers pre-load Windows 7, and let retail customers choose between 7 and 8 on the same hardware at the same price. (Yes, I know one can buy systems loaded with Windows 7 that come with a Windows 8 "upgrade" disk - but they cost more). That Microsoft won't let the market decide, suggests Microsoft is now running on ego, not economics.
One last thought. You can run a diesel engine on any fuel, if the compression ratio is right. Diesel (the inventor) patented one that ran on coal dust, though don't ask me how he got it into the cylinders. In the old days before fuel injection etc. you could run a diesel car or lorry on petrol with nothing short-term worse than loss of power. I'd hope that the army's diesels still can run on anything: diesel, kero, petrol, cooking oil ... In a war your fuel supplies may be adversely affected by the enemy.
So emergency generators should use specialized diesels running on LPG, I think. Of course a bog-standard lorry engine will be cheaper, but at a higher likelyhood of failing when an emergency happens.
I already knew that bacteria can thrive on petrodiesel as well as biodiesel.
Some think that the bacteria that cause problems kilometers underground for the oil industry, are not always introduced into the crude oil by the drilling process. It's possible that life has been surviving there, since the oil was organic-rich sludge at the bottom of a pre-historic sea.
So why do emergency generators run on diesel, not petrol or (best of all? ) LPG?
I think that it has become almost a sport to take a swipe and Unity and Gnome. Anyone who uses Unity everyday will now take an oath to say how good it is.
I have no idea how true I'd believe that to be about Unity, but it's really bad statistics. You are citing a self-selected sample set. In other words, the folks who hate Unity are almost by definition the folks who don't use it. The only exception will be those who are working for an employer who insists that they use it.
As for Gnome, I slagged off the Gnome 3 folks not for producing a UI that I really disliked, but for packaging it in such a way that I couldn't choose to re-install Gnome 2 on a Gnome 3 distribution. They did a Windows 8 "upgrade" on me, which is not the Linux way. Cinnamon and Mate fixed that in two different ways. Mate is the true Gnome-2 fork, but I found that I preferred Cinnamon over Mate and KDE and XFCE (and all these to Gnome-3). Choice is good, especially if one gets it at log-in time.
in passing I think allowing sample self-selection was Microsoft's big mistake with Windows 8. They didn't realize that the folks who contributed during the pre-release by definition liked it, and the folks who hated it had tried it for an hour or two and then just blew it away. And of course, in the MS world one can't just download and use a different UI or three, and very likely one is told what to use by one's employer.
If you like Cinnamon but not so much the rest of the Mint distribution, Cinnamon is also available for Fedora through the standard package installer. In fact downloading Cinnamon is the first thing I do after installing Fedora, because I really dislike Gnome 3 and prefer Ciinnamon to KDE or XFCE. (Haven't checked if Mate is available for Fedora, since Cinnamon made me rather lose interest).
Scientific Linux 7 should be coming fairly soon (3 months after RHEL 7 ships? ), and will be based on Fedora 17. I hope that means I'll be able to install Cinnamon on Scientific Linux, which may come fairly close to perfection in my eyes.
I don't recommend Fedora in general because it's a bit bleeding-edge for my taste, and forces you onto an upgrade treadmill in that there's no long-term support for Fedora releases. However, it does tend to have support for the latest hardware, so I reach for it when SL lacks the hardware support I need.
Is there a commercially supported stable linux that does not charge an arm and a leg for private use ? The coorporate red hat prices are a bit steep I think.
Depends what you mean by "supported".
If you want to pay so there's someone on a phone who will help you with any "issues", there are various organisations out there who will do that for popular distributions. I don't have any experience of who is how good.
If you mean you want the long-term security updates and platform stability that you can get by paying for RHEL, then look at Centos or Scientific Linux. Both are built from RHEL Open source. Both are free. For most usages, they are interchangeable. Both, for example, can use all(?) binary packages from Red Hat's EPEL repository (Extra Packages for Enterprise Linux).
Centos claims 100% bug-for-bug compatibility with RHEL.
Scientific Linux (the most misnamed distribution?) is an almost-clone of RHEL and can be used virtually anywhere that RHEL can. It might also be mis-named "CERN LInux". It's supported at CERN and used extensively by CERN. The not quite a clone bit is that if CERN finds a bug or needs a kernel feature that RHEL don't fix or ship, CERN will fix or build it themselves. In practice I have never found anything that works on RHEL that doesn't work on the same-numbered release of Scientific Linux. It also ships with auto-updating turmed on. Centos ships with that off.
There's always a risk that the Centos distribition might go away. There were reports of bust-ups amongst the project leaders around the time of RHEL 6.0, but it's still with us.
I doubt that Scientific Linux could go away any time before CERN goes away. That makes it my choice for a free Enterprise-grade Linux. YMMV.
What sort of tasks produce this sort of results?
The most spectacular one for me was installing Windows XP + apps (i.e., developing images for deployment). Even after I worked out that VMWare had optimized formatting a virtual disk into an (almost-?) no-op and after adding back the time saved at that point, it was still considerably faster installing into a virgin VM than installing onto the hard disk of the same system natively. Some day, out of curiosity, I may repeat the measurements under native Linux KVM or Virtualbox and with Windows 7, but VMWare workstation on Linux was there first and that's when I was doing this stuff. It's someone else's baby now, and he insists on doing it all the all-MS way.
Why? My guess is that Linux's cacheing of the hard disk to RAM is greatly superior to Windows'. Operations like copying a large folder containing a lot of files were also faster within a VM than when Windows was in direct control of the disk. Or maybe it was just that 32-bit XP couldn't use all 4Gbytes of RAM, but 64-bit Linux could. (In fact so can 32-bit Linux, via PAE, though not all on one single process).
The even greater saving of time was from VMware VM snapshotting. Snapshot - sysprep - image - test depoly - find bugs - what then? On the VM as opposed to a native installation, you just revert to the snapshot, which takes mere seconds (and saves waiting for a boot!), then start fixing the bugs. You can also do much the same at the Linux LVM level, except it's probably a good idea to make sure the VM is shut down at the time you take the snapshot, if the VM is unaware that a snapshot is being taken.
KDE is probably the "heaviest" of the Linux desktops. If you have a powerful desktop system it's OK. As for whether you like the KDE experience ... try it and see. The nice thing about Linux is that you can choose between desktop UIs at log-in time.
But another good thing about Linux is that it can be very usable on elderly hardware, which you can obtain for free or almost-free because it's not man enough to run Windows 7 comfortably. My feeling is that KDE and Windows 7 desktops are similarly demanding. Something lighter is better on such hardware.
Boggle. On any Distro I know, install Chrome or Chromium (or other open browser of your choice) and then forget about Firefox until you are sure you are happy with your chosen replacement. Then use the package manager to un-install Firefox, if you are really keen to reclaim a smallish amount of disk space.
Or you could close your eyes and jump: un-install Firefox first and then install Chrome or whatever. You can always put Firefox back later.
Linux is a perfectly adequate alternative to Windows right now, and has been for years. EXCEPT ...
People often don't want alternatives. They want exact bit-for-bit and feature-for-feature identity. For example, they don't regard Openoffice as an MS office alternative, neither on Linux nor on Windows. Ditto Gimp versus Photoshop (much bigger bucks at stake here). Ditto Octave versus Matlab. Some even object to browsers that aren't MSIE.
And then there are existing organisations that have locked themselves into MS proprietary file formats, and now can't afford to escape. Access databases are one obvious lock-in.
But if you are starting an organisation right now, think long and hard before you let Microsoft get a toe in your door. The best time to break free, is never to enslave yourself in the first place.
It's more a matter of conservatism and long planning stages, resulting in Microsoft "lemons" being squeezed out (sorry) before any deployment happens. IT is there to support the business. Disasters happen when the tail is allowed to wag the dog.
Most enterprises avoided Vista altogether because they were happy with XP for the forseeable future, and their techies were able to say "don't go there" before any serious commitments were made.
Many enterprises are still migrating XP to Windows 7. Many would prefer that XP remained viable forever, but Microsoft have hit the XP kill switch. There's no reason that Microsoft couldn't have incrementally improved XP, including replacing its kernel, without inflicting a painful migration. Or have given us proper migration tools for going from XP to 7. So that was perhaps the first sign of the rot setting in at Microsoft.
The posts above should give you a pretty good idea of what enterprise techies are telling their bosses about Windows 8. Soon, we'll be reading about what happens to the bosses and companies who override their techies because they prefer to believe Ballmer's promises. It'll be interesting. I wonder if it'll take down a bank? (Kidding - I hope). Most companies will wait and watch for now. It's been a good strategy in the past.
IMO "Windows 9" will be the last chance saloon for Microsoft. If they EOL Windows 7 without providing a Windows that enterprises are happy with, the decision will be taken that if there's got to be a really painful migration, then why should it involve Microsoft at all? Until then there is still time for Microsoft to fix things.
Sooner or later if Microsoft carry on the way they are at present, a big company with deep pockets and a long-term plan will decide to challenge Microsoft with a Linux-based Enterprise Desktop and some heavyweight migrate-from-Microsoft support. A company like IBM or Samsung or possibly a company from outside IT altogether. (Anyone remember what Nokia did before entering the mobile phone business? )
Years ago I watched as Digital Equipment self-destructed because of managerial greed, incompetence, and hubris. Now I feel that Microsoft is treading the same path to corporate oblivion.
My thought also: WD and HGST will merge, so duplicating research is pointless. Hydrid drives is WD's job.
As for "robust device drivers" I understand what he is saying. A modern CPU is more powerful than the microcontroller in a hard drive, especially when it comes to algorithms that can't be accelerated by custom hardware. So letting an OS combine an SSD-based cache with conventional disk drives may be the best-performing solution. However, it does require someone to write that driver and to support it. (Is it a hint that post-merger, HGST may be getting into the software business? )
The nice thing about a hybrid drive is that you know exactly who to blame if it mangles your data. I feel pretty confident that the caching in hybrid drives will be robust and reliable, even if it's far from optimal for any particular usage pattern .
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