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@jboner
jboner / latency.txt
Last active September 21, 2025 17:57
Latency Numbers Every Programmer Should Know
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
@todgru
todgru / starttmux.sh
Last active September 26, 2024 04:28
Start up tmux with custom windows, panes and applications running
#!/bin/sh
#
# Setup a work space called `work` with two windows
# first window has 3 panes.
# The first pane set at 65%, split horizontally, set to api root and running vim
# pane 2 is split at 25% and running redis-server
# pane 3 is set to api root and bash prompt.
# note: `api` aliased to `cd ~/path/to/work`
#
session="work"
@joepie91
joepie91 / monolithic-vs-modular.md
Last active September 19, 2024 04:07
Monolithic vs. modular - what's the difference?

When you're developing in Node.js, you're likely to run into these terms - "monolithic" and "modular". They're usually used to describe the different types of frameworks and libraries; not just HTTP frameworks, but modules in general.

At a glance

  • Monolithic: "Batteries-included" and typically tightly coupled, it tries to include all the stuff that's needed for common usecases. An example of a monolithic web framework would be Sails.js.
  • Modular: "Minimal" and loosely coupled. Only includes the bare minimum of functionality and structure, and the rest is a plugin. Fundamentally, it generally only has a single 'responsibility'. An example of a modular web framework would be Express.

Coupled?

In software development, the terms "tightly coupled" and "loosely coupled" are used to indicate how much components rely on each other; or more specifically, how many assumptions they make about each other. This directly translates to how easy it is to repla

@joepie91
joepie91 / vpn.md
Last active September 18, 2025 13:12
Don't use VPN services.

Don't use VPN services.

No, seriously, don't. You're probably reading this because you've asked what VPN service to use, and this is the answer.

Note: The content in this post does not apply to using VPN for their intended purpose; that is, as a virtual private (internal) network. It only applies to using it as a glorified proxy, which is what every third-party "VPN provider" does.

  • A Russian translation of this article can be found here, contributed by Timur Demin.
  • A Turkish translation can be found here, contributed by agyild.
  • There's also this article about VPN services, which is honestly better written (and has more cat pictures!) than my article.
@vasanthk
vasanthk / System Design.md
Last active September 21, 2025 18:35
System Design Cheatsheet

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?
@atoponce
atoponce / gist:07d8d4c833873be2f68c34f9afc5a78a
Last active August 11, 2025 13:19 — forked from tqbf/gist:be58d2d39690c3b366ad
Cryptographic Best Practices

Cryptographic Best Practices

Putting cryptographic primitives together is a lot like putting a jigsaw puzzle together, where all the pieces are cut exactly the same way, but there is only one correct solution. Thankfully, there are some projects out there that are working hard to make sure developers are getting it right.

The following advice comes from years of research from leading security researchers, developers, and cryptographers. This Gist was [forked from Thomas Ptacek's Gist][1] to be more readable. Additions have been added from

@Rich-Harris
Rich-Harris / footgun.md
Last active August 12, 2025 09:57
Top-level `await` is a footgun

Edit — February 2019

This gist had a far larger impact than I imagined it would, and apparently people are still finding it, so a quick update:

  • TC39 is currently moving forward with a slightly different version of TLA, referred to as 'variant B', in which a module with TLA doesn't block sibling execution. This vastly reduces the danger of parallelizable work happening in serial and thereby delaying startup, which was the concern that motivated me to write this gist
  • In the wild, we're seeing (async main(){...}()) as a substitute for TLA. This completely eliminates the blocking problem (yay!) but it's less powerful, and harder to statically analyse (boo). In other words the lack of TLA is causing real problems
  • Therefore, a version of TLA that solves the original issue is a valuable addition to the language, and I'm in full support of the current proposal, which you can read here.

I'll leave the rest of this document unedited, for archaeological

FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.


Effective Engineer - Notes

What's an Effective Engineer?

@joepie91
joepie91 / .md
Created March 25, 2017 22:51
Database characteristics

NOTE: This is simplified. However, it's a useful high-level model for determining what kind of database you need for your project.

Data models

  • Documents: Single type of thing, no relations
  • Relational: Multiple types of things, relations between different types of things
  • Graph: Single or multiple types of things, relations between different things of the same type

Consistency models

@steven2358
steven2358 / ffmpeg.md
Last active September 21, 2025 14:11
FFmpeg cheat sheet