Jim Henderson wrote:
> On Tue, 10 Nov 2009 22:10:55 +0000, Orchid XP v8 wrote:
> 
>> In fairness, when was the last time you tried copying a file that
>> somebody else was still using? Not so easy, is it?
> 
> Trivial on Linux. 

As long as you don't care about correctness. ;-)

-- 
   Darren New, San Diego CA, USA (PST)
   I ordered stamps from Zazzle that read "Place Stamp Here".

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On Tue, 10 Nov 2009 15:59:15 -0800, Darren New wrote:

> Jim Henderson wrote:
>> On Tue, 10 Nov 2009 22:10:55 +0000, Orchid XP v8 wrote:
>> 
>>> In fairness, when was the last time you tried copying a file that
>>> somebody else was still using? Not so easy, is it?
>> 
>> Trivial on Linux.
> 
> As long as you don't care about correctness. ;-)

Depends a lot on a lot of different factors.  Since you're backing up an 
inode, the inode is going to be generally valid (unless it's a special 
file of some sort), but whether it's the version that's being modified in 
memory on some computer somewhere over a network or not depends on when 
the user last saved the file.

Jim

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On Tue, 10 Nov 2009 15:54:56 -0800, Darren New wrote:

> Try to delete files more than a week old out of /tmp without ever giving
> anyone the opportunity to delete /etc/passwd, for example.

I think this is exactly what tmpwatch is intended to do.....

Jim

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clipka wrote:

> Stefan Viljoen schrieb:
>> Huh? That doesn't sound right. An old strategic option the USSR
>> apparently had was to detonate a -real- big (50 megaton) thermonuke over
>> the US, but out in space / low orbit. The idea was to melt all radios and
>> computers, the entire US telephone network, etc. As far as I know EMP
>> damage is caused by the massive radio waves generated by a nuclear
>> explosion (besides all the "hard" gamma radiation, and other nasty stuff
>> besides heat and light). These induce current in conductors (i. e. they
>> fry microchips).
> 
> I think the story is slightly different:
> 
> - A nuclear explosion is caused by nuclear fission and/or fusion
> (actually primarily fission, even in a thermonuke aka H-bomb); the
> radiation given off by this is primarily gamma rays.
> 
> - As the gamma rays hit the atmosphere, they ionize it, turning it into
> a plasma.
> 
> - The plasma in turn "glows" in the whole EM spectrum.

Yes, that does make more sense. I seem to have had the wrong idea then...

-- 
Stefan Viljoen

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clipka wrote:

> Stefan Viljoen schrieb:
> 
>> Makes sense. As far as I know the US military is one of THE most prolific
>> users of the EM spectrum in the world. He's probably got his radar on or
>> in a specific mode - I've read that the "ground tracking" mode on the
>> Hughes / Westinghouse (?) "APG" sets US Navy F-18s (among others) use
>> tend to do this. Apparently the F-22 (or is it the F-35?) have a "burn
>> 'em down" mode on their radars - they are powerful enough to fry the
>> electronics in an enemy plane with a single sweep, instead of shooting it
>> down with a missile.
> 
> Heh, that's cool... they'll never see it coming... they'd better be sure
> to not "burn down" their friendlies though. And enemy fighter jets may
> be hardened against EM radiation. At least I'd expect the newest US
> fighter jets to be.

I'd think that's where IFF would come in. You'd have your radar in some kind
of "auto-burn" mode - first sweep is IFF interrogate, and if the correct
coded response isn't achieved, next sweep is a "burn" sweep.
 
> I guess it'll bee the F-22 though, which in terms of performance as a
> fighter jet seems to be superior to the F-35 (except at being a
> comparatively inexpensive "bread and butter" fighter, which is what the
> F-35 was designed to be). I guess there's a reason why the F-35 is on
> offer to allies, while the F-22 is not.

Well at the prices their quoting, the -22 'd better make coffee, give its
pilot a massage, and take the dog for a walk too.

I'm seriously doubtful about the USAF planning regarding these aircraft. The
F-22 specifically, it is so HORRIBLY expensive, and they have bought much
less than the Air Force generals wanted. If they get into a fight with,
say, China, which has got thousands of Mig-21s and comparable aircraft, I
think they'll get whipped.

The simple reason being the F-22 is so expensive that the budget won't allow
for enough AIM-120's or whatever to be bought. So you got, say, 70 F-22s
sent to Korea or Taiwan for a fight with China (bear with my simplistic
view of international politics.) They take along 200 of the available 600
AIM-120 AMRAAM missiles. They use those to shoot down (perfectly, and at
great range) 175 old, 1950's era MiGs.

But China has a thousand of those cheap aircraft. And the entire USAF has
only 600 AMRAAMs, of which many still have to be shipped to Taiwan or S.
Korea in order to get into the fight.

What happens next? The F-22s go "Winchester" - they have to engage in gun to
gun duels, at low level (where the 60+ year old Chinese Mig-17, for
example, is a KING of maneuverability.) The F-22 now has to go "low and
slow" in the weeds, against a fighter that was DESIGNED for that, while
itself is a beyond-visual-range 30 000 feet plus rather neurotic
thoroughbred. 

It's the Vietnam paradigm all over again, losing a tens of millions of
dollars price F-4 Phantom in blowing up a bamboo bridge that is
reconstructed that very night, with $3 Chinese bicycles once more carrying
ammunition across it for the Viet Cong.

> Hm, are they sure about that? Valve tubes are delicate things, too,
> aren't they? Give the EMP any place to couple in, and the voltages might
> kill the cathodes, I'd guess.

Could be, I'm not sure. I do suspect that valves though, physically larger
and more widely separated than densely packed transistors on a chip, might
have a better survivability? They might "twinge" to different frequencies
on the circuits they are in... plus I'd guess they have a
higher "capacitance" - i. e. they'd be able to absorb more voltage and / or
amperage before failing.

Plus, if they fail, they are much easier to fix, I'd guess. Open the radar
up and simply swop out the ones that have stopped glowing.
-- 
Stefan Viljoen

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Darren New wrote:

> Stefan Viljoen wrote:
>> Maybe not, that's sounds like a good idea! If you can aim and modulate it
>> right a one-second high intensity burst might do the job on a
>> computerised injection and ignition system...
> 
> And your brain. You realize it's basically microwaves, right? Like from
> your oven?

Hahaha! You're right - imagine driving 5 mph too fast and the next moment
your brain boils out of your ears... "I wasn't speeding
officerrrrrrrr...ARGHHH!" :) 

-- 
Stefan Viljoen

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Orchid XP v8 wrote:

>>> Maybe not, that's sounds like a good idea! If you can aim and modulate
>>> it right a one-second high intensity burst might do the job on a
>>> computerised
>>> injection and ignition system...
>> 
>> And your brain. You realize it's basically microwaves, right? Like from
>> your oven?
> 
> Didn't the USA come up with a crowd dispersal device which *actually
> does this*??

Yeah, but it just makes you feel as if you're on fire if you are in the
beam. Most people immediately start moving around alot if they are on fire,
so its basically a second or two of agony and as soon as you move out of
the beam, it stops. 

Which isn't too bad for a crowd control device - anybody hit immediately
runs away, and isn't permanently injured.
-- 
Stefan Viljoen

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Darren New wrote:

> You think dropping a tape and having the case crack and spill tape all
> over doesn't happen, or chipping or cracking a DVD? :-)
 
I've done both, the thing is, a portable HDD has more mass, so it tends to
hurt itself worse when hitting the floor after leaving a hand at 1.2m or so
above the ground.

I've often dropped uncased DVDs (I'm a clumsy oaf sometimes) and I've yet to
break one. Dropped a few DAT tapes as well, and that QIC like crap - never
had a problem.
-- 
Stefan Viljoen

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Invisible wrote:

> Stefan Viljoen wrote:
 
> I'm glad it's not just me who constantly mis-spells "star". :-D

It's my keyboard! The **&%$ keyboard at wrk has its keys all placed one to
the left of my home keyboard.

Oh gods, I just misspelled "work" too!
 
>> To even get to more "close" stuff, 6 YEARS, 10
>> YEARS - or -thousands- of years (at LIGHTSPEED!) to another galaxy.
 
> Indeed. Without warp drive and the ability to vastly exceed the speed of
> light, it will just take such an absurdly long time to go anywhere that
> it doesn't bare thinking about. Think about it: how long ago did we land
> on the moon? And how long after that did we land on Mars? Oh, wait...

... we haven't. Yup, three years out, three years back, or something like
that?

And that's just in our solar system, never mind -real- interstellar stuff.
 
> In fact, half the stars in the night sky probably DON'T EVEN EXIST ANY
> MORE. It's just that it's taken that long for the light to reach us.

Now that's a depressing thought. Spending millions of years getting there,
only to find that the star you were going to went nova or just collapsed in
on itself a few hundred thousands years back.
 
Serious case for some kind of hyperspace or space-warping technology.
-- 
Stefan Viljoen

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Bill Pragnell wrote:

> Optimism, people! It was only a few hundred years ago people thought you'd
> fall apart if you went faster than a galloping horse... :)

Hahaha! Yeah... but I mean, Einstein has been proven right experimentally so
many times, even by items of technology that didn't not exist when he did
his "denk eksperimenten". I may be the typical cro-magnon who won't come
out of the cave and smell the mammoth, but lightspeed DOES seem to be the
ultimate speed limit...
-- 
Stefan Viljoen

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