Fox News demostably has lousy coverage. Numerious media studies have show that people that primarily get their information from Fox News are grossly misinformed.
It's something of a truism that stating what you do/are up front is exactly the opposite of what you really are or do. I understand the motto of Fox News is:
"We report, you decide?"!
As if! That's up there with the "DemocraticPeople's Republic of Korea" [*].
"We report what we think you should think, you decide what we told you to think.
That's at least one good thing with modern communication, it's really quite difficult these days to pull the wool over people's eyes, unless of course they want you too!
--------------
[*] In case there's any ambiguity it's neither democratic, the "People's" or a republic.
When I brought back a bar of the Lindt 99% from Switzerland for people to try one said [I paraphrase]: "Ah chocolate, cool". Before I could introduce him to the ritual of eating it he'd grabbed a nice chunk and started chomping...
lets say it is spinning at 120rpm (pretty fast given how heavy this thing is)
As you elude to, the energy of a flywheel is (to a good approximation):
$1/2 I \omega^2$
where I is the moment of inertia (not the mass) and omega the angular speed. The mass can be surprisingly low, if it's all concentrated away from the axis of rotation. With modern materials and engineering one can obtain very high angular speeds.
Of course Americans work harder than say, Britons. I live in Britain now and OMG they ARE lazy. I would *love* to work here because they just dont work =o).
Their thirty-five hour week isn't a critisism of course, more something for us Brits to aspire too!;-)
...ntry, but they do not know how good they live as some of them have also never go out..
Agreed. For all it's faults - of which there are many - this is still a "green and pleasant land". The fact that the main political parties are generally hard to tell apart indicates to me that we really don't have any significant problems, we like to pretend we do (the usual mantra, Schools, Hospitals etc), but really lets get a sense of perspective!
I keep telling her to switch completely to digital and she tells me I don't know what I am talking about, she is probably right...
I too have a fridge full of film (Velvia, Astia, Provia), however I accept that I'm a dinosaur and proud of it! Modern digital SLRs perform better than 35mm film in practically every respect and challenge medium format in quality. Only with large format is that not true - and large format is something of a niche! Soon of course even this will bow to the digital revolution.
I suspect she's like me, stuck in the past and quite happy to stay there for the time being! There's still something magical about transparency film. The colour reproduction is very special, with a gamut wider than you can sense in either prints or monitors. Although the gamut of modern digital sensors is just as good, there's no way of actually sensing it, as the display devices aren't up to snuff! Wide gamuts make an enormous difference to an image. The colors you see in nature are far more diverse than those that can be reproduced in print or on a computer screen. It's only by actually seeing these things first hand that one can appreciate the difference, prints look strangely grey an lifeless in comparison.
Ah, transparency film!
I'll stop evangelising now - I'm probably preaching to the converted anyway!
Perhaps my conceptual problems stem from sloppy use of nomenclature I've thought of the "kernel" as both a chunk of code and the threads executing the code - clearly incorrect.
At the risk of repeating myself, is the following on the right lines as a set of definitions?
Code - Instructions. Either abstract or at the machine level.
Kernel - A set of code that can be executed by threads.
Thread - A notional concept that executes code.
Task - A collection of threads.
Ah!!
"kernel_task" isn't the kernel, it's a collection of threads that run kernel code, but those aren't the only threads running kernel code - those threads just happen never to have run any userland code, unlike threads associated with other tasks.
I really think that explanation needs a whiteboard! Having read your post hand-in-hand with an overview of XNU I think I nearly "get it". There is still much confusion in my mind however.
My understanding is that the kernel of Darwin is a hybrid of a monolithic kernel (e.g. Linux / Windows) and a pure microkernel (e.g. NeXTstep), presumably this is a pragmatic performance tradeoff.
When you therefore state "kernel_task is the Mach task to which all kernel threads belong"., I assume you are describing just the Mach part of the kernel. In other words the section dedicated to fundemental things such as interprocess communication and virtual memory. I assume that higher level operations that make use of system calls such as network access would not be spawned by Mach, but by userland processes.
Does this imply that Mach is in a sense a process of itself? It sounds sufficiently weird and recursive to be vaguely right; this would explain why one can see the kernel itself in a list of running processes.
Perhaps part of the problem is that "the kernel" is a term that is too ambiguous in this context. It could be used to mean Mach, which is highly fundemental, or the much wider BSD system that exposes a familiar API that user processes can call.
Does my rambling make sense? I know very little CS, I'm just an ignorant physicist and still think preemptive multitasking and virtualisation is dark magic!
...is that the process "kernal task" keeps eating up...
Can anyone give a concise explanation of what "kernel_task" actually is? I have seen some broad chatter and an overview, but nothing significant. I too notice it going banannas from time to time. Then again I use MATLAB and various other memory eaters quite a lot...
I notice there seems to be no mention of ultra/supercapacitors in the wider Slashdot discussion. The role of such devices is completely different to the role of the high frequency capacitors mentioned in the main post, but interesting nevertheless. They were a real surprise to me, then again I havn't done much electronics in earnest for years.
Have you or anyone here had experience with these things? How scary is discharging a 2600F capacitor? Any idea of their effective resistance / inductance?
More stylish than tin foil, a Muji Aluminium card holder. I use one as my wallet, storing everything but coins. It has the added benefit that you absolutely cannot squeeze that one last thing in to your wallet - so it doesn't end up looking like a sphere.
Of course it means I have to take my Oyster card out in order to use it, rather than wave the wallet at the reader - but that's the point!
Slashdot Mirror
Surely you mean you have walked X11 through a 1200bps link?
It's something of a truism that stating what you do/are up front is exactly the opposite of what you really are or do. I understand the motto of Fox News is:
"We report, you decide?"!As if! That's up there with the "Democratic People's Republic of Korea" [*].
"We report what we think you should think, you decide what we told you to think.
That's at least one good thing with modern communication, it's really quite difficult these days to pull the wool over people's eyes, unless of course they want you too!
-------------- [*] In case there's any ambiguity it's neither democratic, the "People's" or a republic.
Bullocks!
The look on his face was priceless!
As you elude to, the energy of a flywheel is (to a good approximation): $1/2 I \omega^2$ where I is the moment of inertia (not the mass) and omega the angular speed. The mass can be surprisingly low, if it's all concentrated away from the axis of rotation. With modern materials and engineering one can obtain very high angular speeds.
The Glenn Flywheel Development Team designed, built and successfully operated the new G2 flywheel to 41,000 RPM on September 2nd, 2004 There's an overview of this technology with links in the Wikipedia article on flywheel energy storage. It's not a new idea, having been used in the 50s to power busses in Switzerland, but with modern material technology it will doubtless undergo a resurgence.When you think of it in terms of the speed of sound, it's pretty impressive, just under half the speed of sound at sea level!
Perhaps that is why so few people were aware of the update, they don't posess psychic powers.
Really it should be half way through the year, 2\pi is after all a full revolution (one year).
Clearly you have never been to France the country practically shuts down over the summer - well everywhere except the beaches!
Their thirty-five hour week isn't a critisism of course, more something for us Brits to aspire too! ;-)
Agreed. For all it's faults - of which there are many - this is still a "green and pleasant land". The fact that the main political parties are generally hard to tell apart indicates to me that we really don't have any significant problems, we like to pretend we do (the usual mantra, Schools, Hospitals etc), but really lets get a sense of perspective!
I too have a fridge full of film (Velvia, Astia, Provia), however I accept that I'm a dinosaur and proud of it! Modern digital SLRs perform better than 35mm film in practically every respect and challenge medium format in quality. Only with large format is that not true - and large format is something of a niche! Soon of course even this will bow to the digital revolution.
I suspect she's like me, stuck in the past and quite happy to stay there for the time being! There's still something magical about transparency film. The colour reproduction is very special, with a gamut wider than you can sense in either prints or monitors. Although the gamut of modern digital sensors is just as good, there's no way of actually sensing it, as the display devices aren't up to snuff! Wide gamuts make an enormous difference to an image. The colors you see in nature are far more diverse than those that can be reproduced in print or on a computer screen. It's only by actually seeing these things first hand that one can appreciate the difference, prints look strangely grey an lifeless in comparison.
Ah, transparency film!
I'll stop evangelising now - I'm probably preaching to the converted anyway!
At the risk of repeating myself, is the following on the right lines as a set of definitions?
Ah!!
"kernel_task" isn't the kernel, it's a collection of threads that run kernel code, but those aren't the only threads running kernel code - those threads just happen never to have run any userland code, unlike threads associated with other tasks.
I see. That makes sense!
Learning things from reading /. Whatever next?
I really think that explanation needs a whiteboard! Having read your post hand-in-hand with an overview of XNU I think I nearly "get it". There is still much confusion in my mind however.
My understanding is that the kernel of Darwin is a hybrid of a monolithic kernel (e.g. Linux / Windows) and a pure microkernel (e.g. NeXTstep), presumably this is a pragmatic performance tradeoff.
When you therefore state "kernel_task is the Mach task to which all kernel threads belong"., I assume you are describing just the Mach part of the kernel. In other words the section dedicated to fundemental things such as interprocess communication and virtual memory. I assume that higher level operations that make use of system calls such as network access would not be spawned by Mach, but by userland processes.
Does this imply that Mach is in a sense a process of itself? It sounds sufficiently weird and recursive to be vaguely right; this would explain why one can see the kernel itself in a list of running processes.
Perhaps part of the problem is that "the kernel" is a term that is too ambiguous in this context. It could be used to mean Mach, which is highly fundemental, or the much wider BSD system that exposes a familiar API that user processes can call.
Does my rambling make sense? I know very little CS, I'm just an ignorant physicist and still think preemptive multitasking and virtualisation is dark magic!
Can anyone give a concise explanation of what "kernel_task" actually is? I have seen some broad chatter and an overview, but nothing significant. I too notice it going banannas from time to time. Then again I use MATLAB and various other memory eaters quite a lot...
Although I used to get annoyed about the miss use of 'PC'
I know, It's just not very PC is it?
..you really cannot offload security to a client. Trust me. ;-)
Hmm. I don't know if I should be confused or suspicious.
This might be surprising for many people; France generates over 3/4 of its electrical energy from nuclear power.
The best example of this has to be the City Slickers fiasco at the Mirror.
I see you are from NZ, I visited there last year, it's a beautiful country....
I was skeptical at first, "Powerpoint-like presentations in LaTeX, you've got to be kidding".
It's fantastic. Absolutely brilliant. A stroke of genius.
Being able to introduce terms of an equation syncronised with bullet points explaining their roles is invaluable.
Have you or anyone here had experience with these things? How scary is discharging a 2600F capacitor? Any idea of their effective resistance / inductance?
The UK also has one million pound notes (~two million USD these days), though they are for "internal use only".
Of course it means I have to take my Oyster card out in order to use it, rather than wave the wallet at the reader - but that's the point!
Still, three of those are roughly in the right direction. I suppose 3/17 ain't bad. It's almost half way to a pass!
- England
- Scotland
- Wales
- Cornwall
- Isle of Man
- Ireland
- The Republic of Ireland
- Channel Islands
- Northern Ireland
- The United Kingdom
- Britain
- Great Britain
- The Falkland Islands
- Gibraltar
- Turks and Caicos Islands
- Bermuda
- The British Isles
There are a few trick ones in there, I'm sure it's also far from comprehensive.You mean KPa? Clearly the SI unit of pressure. The Pavarotti - (Pa). Everyone knows Pascal wasn't much of a singer.