cjbischoff

#!/bin/bash
# Sometimes you need to move your existing git repository
# to a new remote repository (/new remote origin).
# Here are a simple and quick steps that does exactly this.
#
# Let's assume we call "old repo" the repository you wish
# to move, and "new repo" the one you wish to move to.
#
### Step 1. Make sure you have a local copy of all "old repo"
### branches and tags.

cjbischoff

Latency Comparison Numbers
--------------------------
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

cjbischoff

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

cjbischoff

System Design Cheatsheet

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

Basic Steps

1. 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?

cjbischoff

Latency Comparison Numbers
--------------------------
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

cjbischoff

#!/bin/bash
#
# Installs and upgrades OS X tools and command-line utils using [Homebrew] (www.brew.sh). 
# This will use GNU's available toolset.
#

# # #
# Function to install homebrew [ http://brew.sh ]
# # #
install_brew() {

cjbischoff

#!/bin/sh

if [ `which brew | grep 'brew$'` = "" ]; then
    ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"
fi

if [ ! -e ~/.zshrc_local -o `grep '\$(brew --prefix coreutils)/libexec/gnubin' ~/.zshrc_local` = "" ]; then
    echo 'export PATH="$(brew --prefix coreutils)/libexec/gnubin:/usr/local/bin:$PATH"' >> ~/.zshrc_local
fi

cjbischoff

#!/bin/bash
# License: Public Domain.
# Author:  Joseph Wecker, 2012
#
# -- DEPRICATED --
# This gist is slow and is missing .bashrc_once
# Use the one in the repo instead! https://github.com/josephwecker/bashrc_dispatch
# (Thanks gioele)
#
# Are you tired of trying to remember what .bashrc does vs .bash_profile vs .profile?