Yannick yene

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!

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Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns                     on recent CPU
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 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 4X memory

How to set up stress-free SSL on an OS X development machine

One of the best ways to reduce complexity (read: stress) in web development is to minimize the differences between your development and production environments. After being frustrated by attempts to unify the approach to SSL on my local machine and in production, I searched for a workflow that would make the protocol invisible to me between all environments.

Most workflows make the following compromises:

Use HTTPS in production but HTTP locally. This is annoying because it makes the environments inconsistent, and the protocol choices leak up into the stack. For example, your web application needs to understand the underlying protocol when using the secure flag for cookies. If you don't get this right, your HTTP development server won't be able to read the cookies it writes, or worse, your HTTPS production server could pass sensitive cookies over an insecure connection.
Use production SSL certificates locally. This is annoying

	mkdir -p generated

	sips -Z 29 --out generated/iPhoneSettings-29x29.png sourceIcon.png
	sips -Z 58 --out generated/iPhoneSettings-29x29@2x.png sourceIcon.png
	sips -Z 80 --out generated/iPhoneSpotlight-40x40@2x.png sourceIcon.png
	sips -Z 120 --out generated/iPhoneApp-60x60@2x.png sourceIcon.png

	sips -Z 29 --out generated/iPadSettings-29x29.png sourceIcon.png
	sips -Z 58 --out generated/iPadSettings-29x29@2x.png sourceIcon.png
	sips -Z 40 --out generated/iPadSpotlight-40x40.png sourceIcon.png

	package main

	import (
	"log"
	"myserver"
	"net/http"
	)

	const addr = "localhost:12345"

	#!/bin/bash
	# A simple script to backup an organization's GitHub repositories.

	#-------------------------------------------------------------------------------
	# NOTES:
	#-------------------------------------------------------------------------------
	# * User @jimklimov (and probably some others called out in the long comment
	# thread below) have modified this script to make it more robust and keep
	# up with various changes in the GitHub API and response format at:
	# https://github.com/jimklimov/github-scripts

	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

	<!DOCTYPE HTML>
	<html lang="en">
	<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<meta http-equiv="X-UA-Compatible" content="IE=edge">
	<title>My shiny site</title>
	<!-- used some CSS from https://github.com/twbs/bootstrap/blob/v4-dev/dist/css/bootstrap-reboot.css -->
	<style>
	html {