vasanthk

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?

san81

#How to build and install the lp_solve Java extension on Mac OS X:

#Download and expanded lp_solve_5.5_source.tar.gz into a directory named 'lp_solve_5.5'.
#Download and expand lp_solve_5.5_java.zip into a directory named 'lp_solve_5.5_java'.

# 1) Build the lp_solve library.

$ cd lp_solve_5.5/lpsolve55
$ sh ccc.osx

evi1m0

#!/usr/bin/env python
# coding=utf8
# author=evi1m0
# website=linux.im

'''
    12306 Captcha Picture:
    author: Evi1m0@20150316
        1. Download Captcha
        2. Pic Conver Text

sshtmc

#!/bin/bash

HOST=$(hostname)

function install_postfix() {
echo | sudo debconf-set-selections <<__EOF
postfix	postfix/root_address	string	
postfix	postfix/rfc1035_violation	boolean	false
postfix	postfix/mydomain_warning	boolean	
postfix	postfix/mynetworks	string	127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

hellerbarde

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