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Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

General Background and Overview

Probabilistic Data Structures for Web Analytics and Data Mining : A great overview of the space of probabilistic data structures and how they are used in approximation algorithm implementation.
Models and Issues in Data Stream Systems
Philippe Flajolet’s contribution to streaming algorithms : A presentation by Jérémie Lumbroso that visits some of the hostorical perspectives and how it all began with Flajolet
Approximate Frequency Counts over Data Streams by Gurmeet Singh Manku & Rajeev Motwani : One of the early papers on the subject.
[Methods for Finding Frequent Items in Data Streams](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.187.9800&rep=rep1&t

Basecamp was under network attack

The attack detailed below has stopped (for the time being) and almost all network access for almost all customers have been restored. We're keeping this post and the timeline intact for posterity. Unless the attack resumes, we'll post a complete postmortem within 48 hours (so before Wednesday, March 26 at 11:00am central time).

Criminals have laid siege to our networks using what's called a distributed denial-of-service attack (DDoS) starting at 8:46 central time, March 24 2014. The goal is to make Basecamp, and the rest of our services, unavailable by flooding the network with bogus requests, so nothing legitimate can come through. This attack was launched together with a blackmail attempt that sought to have us pay to avoid this assault.

Note that this attack targets the network link between our servers and the internet. All the data is safe and sound, but nobody is able to get to it as long as the attack is being successfully executed. This is like a bunch of people

Better Jasmine Tests With `this`

On the Refinery29 Mobile Web Team, codenamed "Bicycle", all of our unit tests are written using Jasmine, an awesome BDD library written by Pivotal Labs. We recently switched how we set up data for tests from declaring and assigning to closures, to assigning properties to each test case's this object, and we've seen some awesome benefits from doing such.

The old way

Up until recently, a typical unit test for us looked something like this:

describe('views.Card', function() {

-To remove a submodule you need to:
-Delete the relevant line from the .gitmodules file.
-Delete the relevant section from .git/config.
-Run git rm --cached path_to_submodule (no trailing slash).
-Commit and delete the now untracked submodule files.

	guard 'rspec', :version => 2 do
	watch(%r{^spec/.+_spec\.rb$})
	watch(%r{^lib/(.+)\.rb$}) { \|m\| "spec/lib/#{m[1]}_spec.rb" }
	watch('spec/spec_helper.rb') { "spec" }

	# Rails example
	watch(%r{^app/(.+)\.rb$}) { \|m\| "spec/#{m[1]}_spec.rb" }
	watch(%r{^app/(.*)(\.erb\|\.haml)$}) { \|m\| "spec/#{m[1]}#{m[2]}_spec.rb" }
	watch(%r{^app/controllers/(.+)_(controller)\.rb$}) { \|m\| ["spec/routing/#{m[1]}_routing_spec.rb", "spec/#{m[2]}s/#{m[1]}_#{m[2]}_spec.rb", "spec/acceptance/#{m[1]}_spec.rb"] }
	watch(%r{^spec/support/(.+)\.rb$}) { "spec" }

	# Nginx+Unicorn best-practices congifuration guide. Heartbleed fixed.
	# We use latest stable nginx with fresh openssl, zlib and pcre dependencies.
	# Some extra handy modules to use: --with-http_stub_status_module --with-http_gzip_static_module
	#
	# Deployment structure
	#
	# SERVER:
	# /etc/init.d/nginx (1. nginx)
	# /home/app/public_html/app_production/current (Capistrano directory)
	#

	#
	# python drive.py "origin" ["waypoint" ... ] "destination"
	#
	# i.e. python drive.py "Union Square, San Francisco" "Ferry Building, San Francisco" 'Bay Bridge' SFO

	import sys, json, urllib2, md5, os.path, pprint
	from math import radians, sin, cos, atan2, pow, sqrt
	from urllib import quote_plus
	from xml.sax.saxutils import escape
	from optparse import OptionParser

	// Load Ember into the global scope by requiring it
	require('ember');

	// Go have fun
	var app = Ember.Application.create();

	/**
	http://mythosil.hatenablog.com/entry/20111017/1318873155
	http://blog.dealforest.net/2012/03/ios-android-per-aes-crypt-connection/
	*/

	@interface NSData (AES)

	- (NSData )AES128EncryptedDataWithKey:(NSString )key;
	- (NSData )AES128DecryptedDataWithKey:(NSString )key;
	- (NSData )AES128EncryptedDataWithKey:(NSString )key iv:(NSString *)iv;