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?

gboudreau

Generating Authy passwords on other authenticators

---

*update: TBC, but this new might affect how easy it is to use this technique past August 2024: Authy is shutting down its desktop app | The 2FA app Authy will only be available on Android and iOS starting in August

---

This gist, based in part on a gist by Brian Hartvigsen, allows you to export from Authy your TOTP tokens you have stored there.
Those can be "standard" 6-digits / 30 secs tokens, or Authy's own version, the 7-digits / 10 secs tokens.

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

dhh

#!/usr/bin/env bash

# Abort sign off on any error
set -e

# Start the benchmark timer
SECONDS=0

# Repository introspection
OWNER=$(gh repo view --json owner --jq .owner.login)

dvf

If you're using a high-end bluetooth headset on your Macbook Pro it's likely your mac is using an audio codec which favors battery efficiency over high quality. This results in a drastic degradation of sound, the SBC codec is the likely culprit, read more about it here.

Find out what codec you're using

1. Play a song on your headphones
2. Option (⌥) click the Bluetooth button at the top of your screen
3. If you're using AAC or aptX, you can stop here—those are the highest quality codecs.

Change your codec to AAC or aptX

brandonb927

#!/bin/sh

###
# SOME COMMANDS WILL NOT WORK ON macOS (Sierra or newer)
# For Sierra or newer, see https://github.com/mathiasbynens/dotfiles/blob/master/.macos
###

# Alot of these configs have been taken from the various places
# on the web, most from here
# https://github.com/mathiasbynens/dotfiles/blob/5b3c8418ed42d93af2e647dc9d122f25cc034871/.osx

cpursley

PostgreSQL is Enough

• Simplify: move code into database functions
• Just Use Postgres for Everything
• PostgreSQL is the worlds’ best database
• Postgres is eating the database world
• Hacker News discussion

Background and Cron Jobs

kconner

macOS Internals

Understand your Mac and iPhone more deeply by tracing the evolution of Mac OS X from prelease to Swift. John Siracusa delivers the details.

Starting Points

How to use this gist

You've got two main options:

johnnymillergh

" IdeaVim Wiki https://github.com/JetBrains/ideavim/wiki
" Find more examples here: https://jb.gg/share-ideavimrc
" The Essential IdeaVim Remaps https://towardsdatascience.com/the-essential-ideavim-remaps-291d4cd3971b

let mapleader=" "

""" Common settings
set showmode
set scrolloff=5
" Do incremental searching.

moyix

#!/bin/bash

gdb -p "$1" -batch -ex 'set {short}$rip = 0x050f' -ex 'set $rax=231' -ex 'set $rdi=0' -ex 'cont'