Please create an account to participate in the Slashdot moderation system


Forgot your password?

Comment Re:run your Hotwheels car through a loop (Score 1) 264

For the extreme example of the 90 degree bank, when the car is always tilted sideways in the complete loop, gravity will pull it down and the side railing of the track will hold it in place. If there was no gravity, the railing isn't strictly necessary. This situation describes the infinite gravity well of a black hole in the deformed rubber sheet analogy. In this case, yes, the curve will keep the objects from escaping orbit. If, however, the slope of the rubber sheet isn't vertical then no orbit is formed simply by the distortion of the shape. It can bend the path of light but cannot describe an orbit of a satellite or simply the falling of an object towards another object when the object initially starts with no momentum.

For the extreme example of the full loop you describe where the car is upside down at the top of the loop, the car needs to be going fast enough to counteract gravity at the top of the loop. The formula that describes this minimum speed is V^2 / R = g (V is minimum velocity at the top of the loop, R is radius of the loop, g is the gravitational acceleration that must be overcome). Notice that when the car is vertical gravity is pulling the car backwards, which causes it to slow down. It will speed up again by the same amount (if you ignore friction) at the other side of the loop as it's vertical facing downwards. This situation is completely different to the deformed rubber sheet analogy, I'm not even sure why you brought it up.

Comment Re:Whiskey. Tango. Foxtrot. (Score 1) 264

No it doesn't. The reason the bank exerts a sideways force on the car is because gravity pushes downwards, there's an equal and opposite resistive force from the road (Newton's Third Law), and since the road is not perpendicular to the gravitational force this has a vertical and horizontal component. Without gravity, there would be no horizontal component of the resistive force.

Comment Re:BTRFS filesystem (Score 1) 321

My understanding is that Storage Spaces is (as he says) MS's version of ZFS - does it not have the same data-checking features/ performance hit that 'regular' ZFS does?

No, it does not have the same data-checking features. Yes, it has a performance hit. Worst of both worlds. I've used it, and junked it as it was literally an order of magnitude slower than RAID5 via mdadm on Linux and didn't actually add any resiliency over RAID5 or flexibility as to grow an existing pool, you need to add multiple similarly sized drives since it doesn't rebalance. This is despite their marketing claims that you can add mismatched drives in an ad hoc fashion and have it "just work".

The only way to get Microsofts unproven resiliency benefits is to use ReFS in conjunction with mirroring (not parity) on the expensive server editions. Windows 8/8.1 does not support ReFS.

Slashdot Top Deals

Don't compare floating point numbers solely for equality.