Friday, December 25, 2009

"Global Warming"

Damn, there's a lot of confusion, contradicting statements, idiocy, corruption, and lolwut around this topic. Now, I've done an Environmental Engineering course. Hence as an expert who is expertly placed, you can trust me to wade through this muck and give you the right answer.

Let's start from the top. The Greenhouse Effect. No, you won't need Wikipedia for this one. It's simple.

Most things in this world are opaque. Which means they don't allow light to pass through them. The wavelengths of visible light they don't absorb gives them their color.

Gases are mostly transparent due to their low density. This is different from colourless, which means that most gases do not absorb visible light. But when you have a huge amount of air, such as an atmosphere, "transparent" becomes irrelevant.

Different gases in the atmosphere absorb different wavelengths of light. What happens when they absorb it? They re-emit it in a different direction, and often with a different wavelength. Water Vapour, CO2, Methane, Ozone are the major players in this. They absorb visible light and infrared light, and re-emit it as infrared. This is called the Greenhouse effect.

This is a good thing. Without the greenhouse effect, we could not survive. Temperatures on our planet would be extreme, with the average temperature being sub-zero. The major contributor to our survival is water vapour, which keeps a large amount of thermal radiation around Earth.

Disaster strikes when someone decides to pump a bazillion litres of CO2 into the atmosphere every year. What does this do? It's complicated. Complicated enough that we don't know for sure the dynamics of everything it does. It's not as simple as rocking a cradle. The global climate is a chaotic system. Even tiny changes in the initial conditions magnify exponentially and change the result completely. This is why BBC doesn't show more than a week's forecast in weather.

We never just say "OK, T°C increase in global temperature in X years" "Polar ice caps will melt in Y years". That's what uninformed news outlets say. They try to dumb the results and predictions down for the general public, and in the process make them incomplete, inaccurate, or wrong.

This is also why scientists' predictions concerning climate change seem to be "wrong" most of the time. This leads the naive public to assume that we're talking out of our collective arses, and that Climate Change is bogus. And when we try to explain what we meant, people go "NYA NYA NYA, YOU'RE WRONG, NOW STOP MAKING EXCUSES AND SHUT UP". And that's what we do. Because we know we're right. That's the thing about science. It doesn't matter what you think, the truth will stay the truth.

Here's the truth. We don't know exactly what's happening (yes dears, present tense) thanks to our shortsightedness. But we're all bloody damn sure about one thing. Whatever's happening isn't good for us. That's why it's called "Anthropogenic Climate Change" (man-made and not-good-for-man).

Now that I'm done being all dramatic and apocalyptic, I notice I forgot to mention all that stuff about Albedo, Positive feedback loops, Quasi-static equilibrium, cyclic climate change, frog in boiling water, etc. Oh well. Maybe if everyone paid attention in college, I wouldn't have to start from the top and get bogged down in the basics before getting to the interesting stuff.

Sunday, October 25, 2009

What's missing in Btrfs

So, after being completely betrayed[1] by Ext4 not once, but twice, I decided to evaluate my FS options for /home .
  • FAT* are not an option, neither is NTFS.
  • Ext2 is primitive and HFS/HFS+ is just not Linux.
  • JFS is nice, but (atleast parted) doesn't support grow/shrink.
  • I've used XFS before, and found it to be more reliable than Ext4. However, deleting dirs with thousands of small files is too slow (a common operation when compiling)
  • ZFS would've been an option if my earlier experiences with ZFS-FUSE weren't so horrid.
  • Did not even consider NILFS. It's too new, and I don't know much about it.

It ended up being a choice between the reliable Ext3, or the new-fangled Btrfs. Why Btrfs? Because I've been using it as my Gentoo Distfiles and Portage tmpdir since v0.16, and found it to be the /most/ resilient to power failures of all my partitions.

I ended up selecting Ext3 for /home, but let's see why.

What's missing in Btrfs:

  1. Growing the filesystem to the "left" of the partition. The error message when you try this is cryptic (common in btrfs-progs). However, since for other FSes this essentially involves "move to left and grow to right", I suppose the "move" part is what's missing in btrfsctl.
  2. Pathetic ENOSPC handling. It either throws an ENOSPC at around 75% or when the metadata space fills up. Not sure which, but it's supposedly fixed for 2.6.32.
  3. Volumes once created cannot be deleted. Again, fixed in 2.6.32.
  4. Parted doesn't support editing/creating Btrfs partitions. Support for detecting it was proposed recently; but, I still don't see it in either "master" or "next". This is not a Btrfs problem, but certainly affects whether I'd use it.
  5. There were other minor irritants (with btrfs-progs, mostly), but those will go away with time

Ext3 might have bad performance (especially w.r.t fsync), but atleast it's more reliable. In conclusion, I'll use Ext3 in data=ordered mode for /home till 2.6.33 is out; and then I'll convert my Ext3 partition to Btrfs and forever be happy :}

1. betrayed == sending everything into /lost+found after a forced fsck due to an earlier fsck after a power failure

Tuesday, June 9, 2009

I don't understand this

And the fun part is, that I can't understand it. Why? Because even though I'm in college, I can't read or understand Physics papers. The learning curve is too steep.

Learning curve for physics too steep? Just pick up a book about it and read it!

Sure, and to understand the physics involved from the basics, I must learn the math involved. And once I've gone through 3 books for the math, I'd still not be able to understand peer-reviewed physics papers.

What's left? What more do you need to know?

To dive into a peer-reviewed paper, I need to be familiar with the language and syntax that they use. It's almost unreadable to a newcomer to the field. Is it just this paper or does every paper use such convoluted language and bury the facts in irrelevant claims, fancy language and dramatic bold text?

If I somehow get used to that stuff, I need to be familiar every paper of the 5 kazillion or so that it references. Especially so when it references other papers by the same author.

Bah. Anyway, I was trying to read some of the papers published by the people guy at Black Light Power. To see for myself what kind of credence to associate with his claims.

And they're just impossible to read.

I do not like hand-waving, and I do not like pretty pictures or videos. I would like my questions to be answered, or given the means to answer them myself. Papers are supposed to be a way to do that, and I can't. So I don't know what to make of his extraordinary claims.

In case you were wondering what his claims were, he's just about claiming that 40 years of QM is inaccurate because they cannot reconcile with some of his experimental observations (which have been published in peer-reviewed papers, not that I trust anything unless I can see the arguments for myself). Now, this would be something revolutionary, but there's too much such stuff going around, and it's difficult to differentiate the physicists from the crackpots.

All in all, I don't have a clue. He's right that people have a hard time getting away from their dearest theories, and I have been embarrassed by the fact that QM is one thing that no one learns, but rather "Accepts" in school and through college since the Math involved isn't taught at that level.

But really, the only way to challenge something as widely-accepted as HUP, you need a mountain of evidence (Occam's Razor and all that).