/home/vk/misc

Mar 25

masteradept:

FYI - from Sgt. Mad Dog Tracy - As the Chalk Leader for my flight home from Afghanistan, I witnessed the following: When we were on our way back from Afghanistan, we flew out of Baghram Air Field. We went through customs at BAF, full body scanners (no groping), had all of our bags searched, the whole nine yards. Our first stop was Shannon, Ireland to refuel. After that, we had to stop at Indianapolis, Indiana to drop off about 100 folks from the Indiana National Guard. That’s where the stupid started. First, everyone was forced to get off the plane-even though the plane wasn’t refueling again. All 330 people got off that plane, rather than let the 100 people from the ING get off. We were filed from the plane to a holding area. No vending machines, no means of escape. Only a male/female latrine. It’s probably important to mention that we were ALL carrying weapons. Everyone was carrying an M4 Carbine (rifle) and some, like me, were also carrying an M9 pistol. Oh, and our gunners had M-240B machine guns. Of course, the weapons weren’t loaded. And we had been cleared of all ammo well before we even got to customs at Baghram, then AGAIN at customs. The TSA personnel at the airport seriously considered making us unload all of the baggage from the SECURE cargo hold to have it re-inspected. Keep in mind, this cargo had been unpacked, inspected piece by piece by U.S. Customs officials, resealed and had bomb-sniffing dogs give it a one-hour run through. After two hours of sitting in this holding area, the TSA decided not to re-inspect our Cargo-just to inspect us again: Soldiers on the way home from war, who had already been inspected, re-inspected and kept in a SECURE holding area for 2 hours. Ok, whatever. So we lined up to go through security AGAIN. This is probably another good time to remind you all that all of us were carrying actual assault rifles, and some of us were also carrying pistols. So we’re in line, going through one at a time. One of our Soldiers had his Gerber multi-tool. TSA confiscated it. Kind of ridiculous, but it gets better. A few minutes later, a guy empties his pockets and has a pair of nail clippers. Nail clippers. TSA informs the Soldier that they’re going to confiscate his nail clippers. The conversation went something like this:
TSA Guy: You can’t take those on the plane.
Soldier: What? I’ve had them since we left country.
TSA Guy: You’re not suppose to have them.
Soldier: Why?
TSA Guy: They can be used as a weapon.
Soldier: [touches butt stock of the rifle] But this actually is a weapon. And I’m allowed to take it on.
TSA Guy: Yeah but you can’t use it to take over the plane. You don’t have bullets.
Soldier: And I can take over the plane with nail clippers?
TSA Guy: [awkward silence]
Me: Dude, just give him your F**K**G nail clippers so we can get the F**K out of here. I’ll buy you a new set.
Soldier: [hands nail clippers to TSA guy, makes it through security]
To top it off, the TSA demanded we all be swabbed for “explosive residue” detection. Everyone failed, [go figure, we just came home from a war zone], because we tested positive for “Gun Powder Residue”. Who the Hell is hiring these people? This might be a good time to remind everyone that approximately 233 people re-boarded that plane with assault rifles, pistols, and machine guns-but nothing that could have been used as a weapon. Can someone please tell me What the hell happened to OUR country while we were gone?

FYI - from Sgt. Mad Dog Tracy - As the Chalk Leader for my flight home from Afghanistan, I witnessed the following: When we were on our way back from Afghanistan, we flew out of Baghram Air Field. We went through customs at BAF, full body scanners (no groping), had all of our bags searched, the whole nine yards. Our first stop was Shannon, Ireland to refuel. After that, we had to stop at Indianapolis, Indiana to drop off about 100 folks from the Indiana National Guard. That’s where the stupid started. First, everyone was forced to get off the plane-even though the plane wasn’t refueling again. All 330 people got off that plane, rather than let the 100 people from the ING get off. We were filed from the plane to a holding area. No vending machines, no means of escape. Only a male/female latrine. It’s probably important to mention that we were ALL carrying weapons. Everyone was carrying an M4 Carbine (rifle) and some, like me, were also carrying an M9 pistol. Oh, and our gunners had M-240B machine guns. Of course, the weapons weren’t loaded. And we had been cleared of all ammo well before we even got to customs at Baghram, then AGAIN at customs. The TSA personnel at the airport seriously considered making us unload all of the baggage from the SECURE cargo hold to have it re-inspected. Keep in mind, this cargo had been unpacked, inspected piece by piece by U.S. Customs officials, resealed and had bomb-sniffing dogs give it a one-hour run through. After two hours of sitting in this holding area, the TSA decided not to re-inspect our Cargo-just to inspect us again: Soldiers on the way home from war, who had already been inspected, re-inspected and kept in a SECURE holding area for 2 hours. Ok, whatever. So we lined up to go through security AGAIN. This is probably another good time to remind you all that all of us were carrying actual assault rifles, and some of us were also carrying pistols. So we’re in line, going through one at a time. One of our Soldiers had his Gerber multi-tool. TSA confiscated it. Kind of ridiculous, but it gets better. A few minutes later, a guy empties his pockets and has a pair of nail clippers. Nail clippers. TSA informs the Soldier that they’re going to confiscate his nail clippers. The conversation went something like this:

TSA Guy: You can’t take those on the plane.

Soldier: What? I’ve had them since we left country.

TSA Guy: You’re not suppose to have them.

Soldier: Why?

TSA Guy: They can be used as a weapon.

Soldier: [touches butt stock of the rifle] But this actually is a weapon. And I’m allowed to take it on.

TSA Guy: Yeah but you can’t use it to take over the plane. You don’t have bullets.

Soldier: And I can take over the plane with nail clippers?

TSA Guy: [awkward silence]

Me: Dude, just give him your F**K**G nail clippers so we can get the F**K out of here. I’ll buy you a new set.

Soldier: [hands nail clippers to TSA guy, makes it through security]

To top it off, the TSA demanded we all be swabbed for “explosive residue” detection. Everyone failed, [go figure, we just came home from a war zone], because we tested positive for “Gun Powder Residue”. Who the Hell is hiring these people? This might be a good time to remind everyone that approximately 233 people re-boarded that plane with assault rifles, pistols, and machine guns-but nothing that could have been used as a weapon. Can someone please tell me What the hell happened to OUR country while we were gone?

(via jhameia)

Nov 27

(via curiousritualizedthievery)

“

I’ve never heard of an abuser saying, “I hit you because I wanted to terrorize you into submission.” Instead he might say,“I wouldn’t have hit you if you wouldn’t have kept yelling and yelling and yelling at me about coming in so late.” The framing conditions caused his violence. If we move this to a larger scale, how often have we heard politicians speak of the necessity of preemptive attacks on other countries (which just happen to sit atop coveted resources)? They rarely say,“I choose to invade this country.” Instead they say they’ve been forced into this regrettable action by those they are about to subjugate, er, liberate. The Nazis played this same card—everybody plays this same card—they only invaded Poland because they had no choice; they only invaded the Soviet Union because they had no choice; they only killed untermenschen because they had no choice. Sigh. It’s a terribly dirty job, but somebody’s got to do it.

CEOs follow the same logic. If it were up to them, they would keep factories open (not that this is a good thing from the perspective of the planet, but within the confines of this culture most people consider it good), pay workers livable wages, maintain solid retirement programs, and so on. But you know how things are. They have no choice but to lay off workers and move the factories to Bangladesh, where they have no choice but to pay Bangladeshis eight cents per hour (as they themselves pull down a cool million per year, which converts to about five hundred dollars per hour, or more in one minute than they pay a Bangladeshi for a hundred hours). And if the Bangladeshis complain, the CEOs will have no choice but to move the factory on to Vietnam. Market pressures, you know. And these same market pressures force them to pollute, to clearcut, to overfish.

I’m sorry, each and every one of us can say, we have no choice but to destroy the planet. It’s really not our fault.

Bullshit.

We may as well acknowledge that our entire culture—from top to bottom, inside out, personally and socially—is founded on, motivated by, and requires a systematic and absolute avoidance of responsibility. This is true both for our actions and our failures to act. What, ultimately, is environmental degradation? Any and all environmental degradation is a manifestation and a consequence of avoidance of responsibility. What is pollution? It is a manifestation and a consequence of avoidance of responsibility. What is overfishing? Deforestation? They are manifestations and consequences of avoidance of responsibility.

And what is our failure to stop each of these things? It’s just as much an avoidance of responsibility.

” Derrick Jensen, Endgame (via cultureofresistance)

(via curiousritualizedthievery)

Nov 9

wild chocolate: A Letter to the Developer Community

wildchocolate:

Dear Mac/iOS Developer Community,

Empathy is the ability to put yourself in someone else’s shoes who may be different from yourself and attempt to understand/have compassion towards that person’s feelings, especially if their feelings are different from your own. If you do not consider yourself…

Aug 3

SICP is Under Attack (Updated)

An Update

SICP will not be abandoned at Berkeley.

Although Python will be used to convey the material, I have been assured that much of the content from SICP will be preserved.

I recognize now that CS61A is a fusion of sorts: an exciting modern treatment of traditionally intellectual material. This change reflects concerns about the difficulty of SICP, the popularity of Python, and a general lack of interest on the part of students and teachers in Scheme. Fair enough. I think this is the best possible solution for an introductory course, but that’s just my opinion.

I want to reiterate that I mean Berkeley or its professors no disrespect, and that I only raised this issue because I was concerned about a potentially drastic shift in the curriculum.

I can’t begin to thank you all for your comments, criticism, emails, and interest. It’s made a world of difference.

(The original essay can be found below, but I am no longer worried about the intellectual rigor of the course at Berkeley.)

Original Essay

It’s official. UC Berkeley will soon join MIT and several other universities in abandoning Structure and Interpretation of Computer Programs, widely regarded as one of the best textbooks in computer science, in favor of alternative material covering Python.

This is a mistake.

SICP is revered for its wit, clarity, and brilliance. It expands the mind. It rewards creativity. There have even been reports of it inducing paroxysms of joy.

The best thing that can be said about SICP is that it will make you a better programmer. It discusses crucially important topics like problem decomposition and the performance implications of various types of procedures. It initiates profound changes in the way you plan and think about code. Although the text is based on Scheme, its teachings are timeless and essentially language agnostic.

This is where most of its competition fails.

Berkeley’s intended replacement for SICP, Dive Into Python, will make you a better Python programmer. Another candidate, Thinking In Java, will make you a better Java programmer. A third option, Thinking In C++, will no doubt make you a better C++ programmer. From an educational standpoint however, none of these alternatives are satisfactory. The sad truth is that SICP’s gradual removal from computer science curricula has left behind a gaping hole that few other texts can hope to fill.

To understand what makes SICP so special, you have to immerse yourself in it. So get ready.

To Slay a Dragon!

One of the earliest topics covered in SICP is linear recursion and iteration. At one point, you are asked to implement the function:

    f(n) = n, n < 3
    f(n) = f(n-1) + 2f(n-2) + 3f(n-3), n >= 3

It’s straightforward to translate this definition into Scheme:

But SICP challenges us to do better. Much better.

If you look carefully, you’ll find three recursive function calls in f that deal with what happens when n >= 3. The top-level call to f(n-1) spawns three calls, each of which spawn three more, and so on, until the recursion terminates with the case n < 3 in each chain of calls. This process is repeated for the calls to f(n-2) and f(n-3).

All of this is incredibly wasteful. After f(n-1), f(n-2), …, f(2) is evaluated, redundant work is performed to calculate f(n-2), f(n-3), …, f(2), and then again for every chain of calls starting with f(n > 3). The challenge, then, is to convert this resource-hungry recursive process into an efficient iterative one.

When I first encountered this problem, I thought it seemed trivial. I was quickly humbled. After a few messy attempts at a solution, I decided that the challenge was outright impossible. I had attacked the dragon with a dull butter knife and all the raging ferocity of a domesticated panda. It was not amused.

The issue I was having was that each term in f(n) has an enormous amount of dependencies. I couldn’t figure out how to represent these dependencies in a reasonable amount of state, or how to update that state without making the same class of huge, branching function calls that I needed to avoid. Sketching these dependencies out on paper didn’t help: it turns out that attempting this for any large n is a lot like playing by the rules in Duel Monsters (tm). It’s tedious, and the cool kids don’t bother with it anyway.

A Revelation

I pondered iterative processes for a solid hour before having a sudden rush of understanding. Everything became blindingly simple. Instead of trying to work my way down from f(n), f(n-1), …, f(n-k), what would happen if I started with the base case and worked my way up? What would happen if I isolated what I already knew into some basic state and then devised some logical mechanism to update it? Wouldn’t I eliminate the need to keep track of all of those dependencies?

It all fell into place. You would probably be safe in comparing that moment to a religious experience. Not having ever seriously tried religion, I can’t say for sure.

The epiphany involved the realization that f(n) can be decomposed into three distinct bits of state, or variables. Specifically:

    a = f(n-1)
    b = 2f(n-2)
    c = 3f(n-3)
    f(n) = a + b + c

The values of f(n < 3) are obvious. The first n that we have to make a real attempt to calculate is n = 3. That leads us to:

    f(3) = a + b + c
    f(3) = f(2) + 2f(1) + 3f(0)
    a, b, c = {2, 2, 0}

Before updating our state from f(n) to f(n+1), consider how things would change algebraically:

    a' = f(n+1-1) = f(n)
    b' = 2f(n+1-2) = 2f(n-1)
    c' = 3f(n+1-3) = 3f(n-2)
    f(n+1) = f(n) + 2f(n-1) + 3f(n-2) = a' + b' + c'

Then update the state using the first set of definitions:

    a' = f(n) = a + b + c
    b' = 2f(n-1) = 2a
    c' = 3f(n-2) = 3b/2

The value of f(n), of course, can be discerned at any time:

    f(n) = a'

Beautiful.

The dragon is slain.

Reflect on What Just Happened

Stop. Take a deep breath. Think about all that you have just discovered (or if you have already discovered it all, reflect on how awesome it is). By page 45 of SICP, you will have;

Translated recursive definitions into iterative processes
Examined the differences in the space requirements of various processes
Used tail-recursion to implement efficient iterative procedures
Seen that iteration can be thought of as a special case of recursion
Realized that iterative processes can be restarted easily by capturing and restoring their state variables
Given thought to complexity, optimization, and state transition theory
Been encouraged to explore creative solutions to challenging problems
Learned the basic syntax and semantics of Scheme
Observed a quasi-religious experience

What will you have accomplished by page 45 of Dive Into Python? Don’t hold your breath. I’ve looked into it. You’ll be learning how to use the and-or “trick” to make simple programs difficult to read. Soon afterwards you’ll be exposed to Python’s intentionally crippled lambda statement.

I find it hard to believe that any young, aspiring computer scientist would prefer that to what SICP has to offer. It’s just.. it’s just not the same. So why are we chucking SICP out of the classroom?

Burn the Wizard Books?

“Python is more practical than Scheme.”

I more or less agree with you. I love Python. I’ve been using it for 5 years to build all kinds of things. I realize that you are far more likely to use Python than Scheme when working. None of this means that you have nothing to gain from SICP. I previously claimed that SICP is fairly language agnostic, and I stand by that. It instills something deeper and more important than knowledge about how to glue APIs together, or how to deal with the vagaries of string encoding, or how to abuse the syntax of a language. It’s so much more than that.

“Why shouldn’t students start with Python if it is the more practical language?”

Scheme is considerably less complicated and idiosyncratic than Python. It’s simplicity and consistency have immense pedagogical value. It might take you anywhere from a day to a month to pick up the basics of Python. Scheme, on the other hand, has virtually no syntax. It’s definitely possible to get a solid grasp of its fundamentals in less than an hour.

Python can be used to accomplish many of the same things as Scheme. Practically anything you can do in Scheme you can do in Python, and formally speaking, the two languages are equivalent.

However, until a Python textbook emerges that surpasses SICP in teaching the core elements of programming, we should stick with Scheme.

“But.. but everyone else is doing [LanguageFoo]! What about the job market!?”

Think about it this way. What if the language du jour happened to be BrainF—-? What if there were plenty of lucrative opportunities in this hypothetical mainstream BrainF—- programming scene? Would you switch introductory computer science courses over to BrainF—- because industry leaders complained about the low quality of your school’s BrainF—- programmers? Hopefully not.

“You are not qualified to comment on pedagogy.”

You’re probably right. I’m just a student, but I do care about the state of computer science education. Given how much I’m paying for it, I feel like I’ve at least earned the right to criticize it.

A Plea

I respect the Berkeley CS department’s decision to try Python for its introductory course. I’m sure that the decision was well-meaning, and who knows, things may even turn out for the best this way.

That said, I really hate to see SICP on its deathbed at Berkeley. Dive Into Python, whatever its merits, is certainly not an adequate replacement. Not if you want students to walk away with a deep appreciation for the elegance and power of their field. I was looking forward to CS61A over the summer and received an unpleasant surprise when I heard rumors of change… A lot of students will be missing out on a great program this fall.

Please help me raise awareness about this issue. I don’t know if the department can be convinced to reverse their decision, but I hope that’s the case.

I’ll take the musings of Ben Bitdiddle over XML parsing 101 any day. Any day.

-vk

Aug 1

An excellent Vader:

Darth Vader // by ScottyShoemaker

Dec 30

Hacking an FPS for fun but not profit

I’ve been playing AssaultCube recently. I love it. It’s a fast, minimal, and strangely addicting FPS. It’s also the first game that I’ve tried joining multiplayer servers with. I was curious about what type of cheating detection game servers do, so I downloaded the source and started reading. I soon came across this;

Cheat Protection: The cheat protection described in README_CUBEENGINE.txt is not used in AssaultCube. Binaries compiled from source are compatible with the official binaries… You MUST NOT connect to servers that are not yours with a modified client that contains changes that were not made for platform-compatibility or to fix bugs. This would be cheating. Thank you for supporting fair play gaming.

After a few more minutes of searching I started making changes to source/src/weapon.cpp — just to see what the results would look like. In the end, I decided to grant myself unlimited ammo, reduced reload time, and damage-steroids.

With great power comes great responsibility. These changes do still work when you join a game server: don’t use them. If you’re feeling savage, you can hack around the codebase and allow yourself to carry out unspeakable acts of cruelty against the helpless bots. Feel free to do all of this on your local machine. People online will notice if your assault rifle starts spewing grenades and they will kick you.