Daniel Okey-Okoro okeyokoro

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

One-line Tree in Python

Using Python's built-in defaultdict we can easily define a tree data structure:

def tree(): return defaultdict(tree)

That's it!

Default

Powerlevel10k

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

	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

	class Graph:
	def __init__(self):
	self.nodes = set()
	self.edges = defaultdict(list)
	self.distances = {}

	def add_node(self, value):
	self.nodes.add(value)

	def add_edge(self, from_node, to_node, distance):

	#
	# CORS header support
	#
	# One way to use this is by placing it into a file called "cors_support"
	# under your Nginx configuration directory and placing the following
	# statement inside your location block(s):
	#
	# include cors_support;
	#
	# As of Nginx 1.7.5, add_header supports an "always" parameter which

	sudo yum install gcc python27 python27-devel postgresql-devel
	sudo curl https://bootstrap.pypa.io/ez_setup.py -o - \| sudo python27
	sudo /usr/bin/easy_install-2.7 pip
	sudo pip2.7 install psycopg2

	;; The code below was translated from the Erlang ring benchmark hosted
	;; at http://benchmarksgame.alioth.debian.org, written by Jiri Isa and
	;; optimized by Shun Shino:
	;; http://goo.gl/5YOjg3
	;;
	;; The LFE version split the logic of the above-mentioned Erlang code
	;; into more functions for increased clarity.
	;;
	(defmodule ring
	(export

	"""
	Some python code for
	Markov Chain Monte Carlo and Gibs sampling
	by Bruce Walsh
	"""


	import numpy as np
	import numpy.linalg as npla