Olov Sundström coolov

The introduction to Reactive Programming you've been missing

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Hofstadter on Lisp

In the mid-80s, while reading through my roommate's collection of Scientific American back issues, I encountered this introduction to Lisp written by Douglas Hofstadter. I found it very charming at the time, and provide it here (somewhat illegally) for the edification of a new generation of Lispers.

In a testament to the timelessness of Lisp, you can still run all the examples below in emacs if you install these aliases:

(defalias 'plus #'+)
(defalias 'quotient #'/)
(defalias 'times #'*)
(defalias 'difference #'-)

If you prefer VirtualBox or aren't running OS X, here are some instructions and a script to help you get started with SmartOS under VirtualBox. If you use VirtualBox, skip the first section and read the section on how to get the Node.js SmartMachine up and running.

Running SmartOS under vmware Fusion

Start by downloading the latest live image
When you run the new VM wizard, select "Continue without disk" on the first screen of the wizard.
Select Sun Solaris / Solaris 10 64-bit on the next screen.
You're going to get dumped to a config screen when the live image starts up, choose DHCP for the networking and defaults for everything else.
Pretty much the first thing you're going to want to do is figure out how to SSH into the box once it boots and creates its storage pools, because trying to do stuff in the virtual console is miserable. There's no cut and paste

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

	(ns ical.core
	(:require
	[om.core :as om :include-macros true]
	[om.dom :as dom :include-macros true]
	[sablono.core :as html :refer-macros [html]]))

	(enable-console-print!)

	(def weekdays ["saturday" "monday" "tuesday" "wednesday" "thursday" "friday" "sunday"])

	#!/usr/bin/env node

	// (c) 2012-2013 Instant Communication Bhd, under terms of ISC License.
	//
	// Process index.html to add md5ized path mapping for RequireJS.
	//
	// Needs empty CacheBust variable to be defined (see replacement logic), which
	// afterwards should be used in `require.config({paths: CacheBust});` call.

	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

	/*
	* This work is free. You can redistribute it and/or modify it under the
	* terms of the Do What The Fuck You Want To Public License, Version 2,
	* as published by Sam Hocevar. See the COPYING file for more details.
	*/
	/*
	* Easing Functions - inspired from http://gizma.com/easing/
	* only considering the t value for the range [0, 1] => [0, 1]
	*/
	EasingFunctions = {

	#!/bin/bash

	# <UDF name="ssh_key" Label="Paste in your public SSH key" default="" example="" optional="false" />

	# root ssh keys
	mkdir /root/.ssh
	echo $SSH_KEY >> /root/.ssh/authorized_keys
	chmod 0700 /root/.ssh

	# update to latest