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

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

paulodeleo

# Make mouse useful in copy mode
setw -g mode-mouse on

# Allow mouse to select which pane to use
set -g mouse-select-pane on

# Allow mouse dragging to resize panes
set -g mouse-resize-pane on

# Allow mouse to select windows

martijnvermaat

IPython Notebook on an SGE cluster

This guide documents how we set up an easy workflow for using the IPython Notebook on our compute cluster managed with Sun Grid Engine (SGE).

Summary: We provide a script to the cluster users that runs qrsh to schedule an ipython notebook job using SSL and password protection.

Installing IPython

dashed

/*! normalize.css v2.1.3 | MIT License | git.io/normalize */

/* ==========================================================================
   HTML5 display definitions
   ========================================================================== */

/**
 * Correct `block` display not defined in IE 8/9.
 */

SteveBenner

#!/usr/bin/env ruby
#
# CLI tool for locating and removing a Homebrew installation
# http://brew.sh/
#
# Copyright (C) 2014 Stephen C. Benner
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or

gbaman

Raspberry Pi Zero OTG Mode

Simple guide for setting up OTG modes on the Raspberry Pi Zero - By Andrew Mulholland (gbaman).

The Raspberry Pi Zero (and model A and A+) support USB On The Go, given the processor is connected directly to the USB port, unlike on the B, B+ or Pi 2 B, which goes via a USB hub.
Because of this, if setup to, the Pi can act as a USB slave instead, providing virtual serial (a terminal), virtual ethernet, virtual mass storage device (pendrive) or even other virtual devices like HID, MIDI, or act as a virtual webcam!
It is important to note that, although the model A and A+ can support being a USB slave, they are missing the ID pin (is tied to ground internally) so are unable to dynamically switch between USB master/slave mode. As such, they default to USB master mode. There is no easy way to change this right now.
It is also important to note, that a USB to UART serial adapter is not needed for any of these guides, as may be documented elsewhere across the int

gbaman

Setting up Pi Zero OTG - The quick way (No USB keyboard, mouse, HDMI monitor needed)

More details - http://blog.gbaman.info/?p=791

For this method, alongside your Pi Zero, MicroUSB cable and MicroSD card, only an additional computer is required, which can be running Windows (with Bonjour, iTunes or Quicktime installed), Mac OS or Linux (with Avahi Daemon installed, for example Ubuntu has it built in).
1. Flash Raspbian Jessie full or Raspbian Jessie Lite onto the SD card.
2. Once Raspbian is flashed, open up the boot partition (in Windows Explorer, Finder etc) and add to the bottom of the config.txt file dtoverlay=dwc2 on a new line, then save the file.
3. If using a recent release of Jessie (Dec 2016 onwards), then create a new file simply called ssh in the SD card as well. By default SSH i

popey

#!/bin/bash
# Automatically setup routing and DNS for a PiZero connected over a USB-network
# Based off https://gist.github.com/lurch/ad939bbce48064cffdb215268eac9f62
# Need to have booted PI Zero with config.txt option "dtoverlay=dwc2"
# and cmdline.txt parameter "modules-load=dwc2,g_ether"
# TODO
# Force PI to have fixed MAC address like e6:45:88:d0:85:46
# For now, edit cmdline.txt in the boot partition on the pi SD card, add:-
# g_ether.dev_addr=e6:45:88:d0:85:46

slint

1. Create an access token at "https://zenodo.org/account/settings/applications/tokens/new/" with the "deposit:write" and "deposit:actions" scopes, and keep it somewhere safe (we'll refer to this token as ZENODO_TOKEN)
2. Create your deposit via the web interface at "https://zenodo.org/deposit/new", fill in the minimum metadata (title, authors, description, access rights and license) and click "Save".
3. On your browser's URL, you will now see the deposit ID in the form "https://zenodo/deposit/".
4. Next step is to get the file upload URL. Via curl (or your HTTP client of preference) you can do:

$ # Store the Zenodo token in an envionrment variable
$ read -s ZENODO_TOKEN
$ curl "https://zenodo.org/api/deposit/depositions/222761?access_token=${ZENODO_TOKEN}"
{ ...