chitchcock

Stevey's Google Platforms Rant

I was at Amazon for about six and a half years, and now I've been at Google for that long. One thing that struck me immediately about the two companies -- an impression that has been reinforced almost daily -- is that Amazon does everything wrong, and Google does everything right. Sure, it's a sweeping generalization, but a surprisingly accurate one. It's pretty crazy. There are probably a hundred or even two hundred different ways you can compare the two companies, and Google is superior in all but three of them, if I recall correctly. I actually did a spreadsheet at one point but Legal wouldn't let me show it to anyone, even though recruiting loved it.

I mean, just to give you a very brief taste: Amazon's recruiting process is fundamentally flawed by having teams hire for themselves, so their hiring bar is incredibly inconsistent across teams, despite various efforts they've made to level it out. And their operations are a mess; they don't real

aprell

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <setjmp.h>
#include <assert.h>
#include <unistd.h>
#include <time.h>
#include "list.h"

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

yamaya

# Xcode 4.3.3
Apple clang version 3.1 (tags/Apple/clang-318.0.61) (based on LLVM 3.1svn)
Target: x86_64-apple-darwin11.4.0
Thread model: posix

# Xcode 4.3.2
Apple clang version 3.1 (tags/Apple/clang-318.0.58) (based on LLVM 3.1svn)
Target: x86_64-apple-darwin11.4.0
Thread model: posix

badboy

Original link: http://www.concentric.net/~Ttwang/tech/inthash.htm
Taken from: http://web.archive.org/web/20071223173210/http://www.concentric.net/~Ttwang/tech/inthash.htm
Reformatted using pandoc

Integer Hash Function

Thomas Wang, Jan 1997

last update Mar 2007

FenwickTreeBitmap32.cs

namespace TryOuts
{
    using System;
    using System.Diagnostics;
    using System.Runtime.CompilerServices;

    /// <summary>
    /// Tracker for usage of a block of 32 consecutive slots. Implemented as a 
    /// Fenwick tree with indexing optimized for queries. Encodes this 
    /// information into a long (64 bit) value, while leaving the high bit 

UsageTrackingBlock.cs

namespace TryOuts
{
    using System.Linq;
    using System.Diagnostics;
    using System.Collections.Generic;

    /// <summary>
    /// Tracks usage of a block of 2^14 (16384) slots using a bitmap that 
    /// contains the 16384 used/free bit flags for each slot (taking up a 
    /// total space of 2048 bytes, accessed as an array of 512 ints), in 

tmoertel

Tom Moertel <tom@moertel.com>
2013-12-16

We are given the following problem:

    Given a text file with 999,999 lines, one number per line,
    numbers in random order from 1 to 1,000,000 but a single number is
    missing, figure out what number is missing.

    Source: http://blog.moertel.com/posts/2013-12-14-great-old-timey-game-programming-hack.html#comment-1165807320

Faxn

import argparse, locale, timeit, random
from math import *

"""
We are given the following problem:
 
Given a text file with 999,999 lines, one number per line,
numbers in random order from 1 to 1,000,000 but a single number is
missing, figure out what number is missing.
Source: http://blog.moertel.com/posts/2013-12-14-great-old-timey-game-programming-hack.html#comment-1165807320

OliverUv

#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define rgbtoy(b, g, r, y)						\
    y=(unsigned char)(((int)(30*r) + (int)(59*g) + (int)(11*b))/100)

#define rgbtoyuv(b, g, r, y, u, v)					\