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

jgstew

__RelaySelect_Automatic=1
_BESClient_Resource_StartupNormalSpeed=1
_BESClient_Download_RetryMinutes=1
_BESClient_Download_CheckAvailabilitySeconds=120
_BESClient_Resource_WorkIdle=20
_BESClient_Resource_SleepIdle=500
_BESClient_PowerHistory_EnablePowerHistory=1
_BESClient_Comm_WakeOnLanForwardingEnable=1
_BESClient_Comm_CommandPollEnable=1
_BESClient_Comm_CommandPollIntervalSeconds=7200

rehno-lindeque

Setup NixOS (Virtualized + Haskell + Gnome3 + XMonad)

Before you get started

This is pretty out of date now... you may want to look elsewhere

Newer guides than mine (mine is a bit dated and has a lot of rough edges):

• NixOS on MacBook Pro

Have you looked at these?

erincerys

#!/bin/bash

# Install dependencies for creating filesystem and installing bootloader
## This script is mostly system-independent, except for this part. Replace yaourt and the args with your own package manager
yaourt -S --noconfirm mtools syslinux dosfstools

# Plug in the flash drive, and find its device. Don't mount it.
lsblk
while [[ $(echo $FLASHDEV | grep -c \/dev\/sd[a-z]) -lt 1 && -b "$FLASHDEV" ]] ; do
	read -p 'Which device (e.g. /dev/sdf)? ' FLASHDEV

martijnvermaat

Installation of NixOS with encrypted root

These are my notes on instaling NixOS 16.03 on a Lenovo ThinkPad X1 Carbon (4th generation) with an encrypted root file system using UEFI.

Most of this is scrambled from the following pages:

• Encrypted Root on NixOS - Nix Wiki
• Installing NixOS - Chris Martin
• Linux administration and use - Earl Douglas
• Installing NixOS on a ThinkPad W540 with encrypted root - Bluish Coder

iAnatoly

[System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes("SecretMessage"))
[System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String("U2VjcmV0TWVzc2FnZQ=="))

tusing

RGB Underglow Strip on the Zeal60: A Guide

A. Connecting the strip

You might find the full PCB image helpful. Ignore the red boxes!

1. Connect V+ to the receiving end of the thermistor labeled F1; connect GND to the board's GND pin. (Avoid connecting +V to the board's +5V pin - you will likely overload the thermistor, and you will limit your maximum brightness.)

nadavrot

High-Performance Matrix Multiplication

This is a short post that explains how to write a high-performance matrix multiplication program on modern processors. In this tutorial I will use a single core of the Skylake-client CPU with AVX2, but the principles in this post also apply to other processors with different instruction sets (such as AVX512).

Intro

Matrix multiplication is a mathematical operation that defines the product of

bee-san

# based off of this code https://gist.github.com/nandajavarma/a3a6b62f34e74ec4c31674934327bbd3
# Brandon Skerritt
# https://skerritt.tech

def binary_search(the_array, item, start, end):
    if start == end:
        if the_array[start] > item:
            return start
        else:
            return start + 1

ctsrc

Guide: Run FreeBSD 13.1-RELEASE for ARM64 in QEMU on Apple Silicon Mac (MacBook Pro M1, etc) with HVF acceleration (Hypervisor.framework)

This guide was adapted from https://gist.github.com/niw/e4313b9c14e968764a52375da41b4278#running-ubuntu-server-for-arm64

Running FreeBSD 13.1-RELEASE for ARM64

1. Install Xcode from App Store or install Command Line Tools on your Mac running on Apple Silicon.