jboner

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

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

steven2358

FFmpeg cheat sheet

A list of useful commands for the FFmpeg command line tool.

Download FFmpeg: https://www.ffmpeg.org/download.html

Full documentation: https://www.ffmpeg.org/ffmpeg.html

Basic conversion

huyng

#!/usr/bin/env python
# Reflects the requests from HTTP methods GET, POST, PUT, and DELETE
# Written by Nathan Hamiel (2010)

from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler
from optparse import OptionParser

class RequestHandler(BaseHTTPRequestHandler):
    
    def do_GET(self):

krishashok

sgillies

Author: Sean Gillies Version: 1.0

Abstract

This document describes a GeoJSON-like protocol for geo-spatial (GIS) vector data.

Introduction

fperez

jaseemabid

A bunch of good git tutorials

Intro to git

• Simplest intro to git by github and codeschool - Try Git

• PeepCode Git Internals PDF

• [Intro to github]

lovettbarron

# So this is a somewhat manual but not nearly as manual as it could be process.
# First, follow the instructions here: https://www.themodernnomad.com/audible-statistics-extractor/
# Depending on how many pages, copy and paste the results into Excel 
# (it will auto format, though you will need to remove the header)

# Before running
# Install the required libraries: pandas and isbntools
# Modify the read_excel argument to point at your file.
# Then point the to_csv argument to wherever you want to export to.

lelandbatey

Description

This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.

The script is here:

#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"

Results