mashingan

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

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?

Source: man syscall

Architecture calling conventions

Every architecture has its own way of invoking and passing arguments to the kernel. The details for various architectures are listed in the two tables below.

The first table lists the instruction used to transition to kernel mode, (which might not be the fastest or best way to transition to

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

Why I Recommend to Avoid Using the `go-kit` Library

There is a trending 'microservice' library called go-kit. I've been using the go-kit library for a while now. The library provide a lot of convenience integrations that you might need in your service: with service discovery with Consul, distributed tracing with Zipkin, for example, and nice logic utilities such as round robin client side load balancing, and circuit breaking. It is also providing a way to implement communication layer, with support of RPC and REST.

First suggestion:

src/
  <pkgname>.nim
tests/
docs/
<pkgname>.nimble # with srcDir = "src"

library with single module

Download Audio from YouTube

-i - ignore errors

-c - continue

-t - use video title as file name

--extract-audio - extract audio track

	public class Sample1
	{
	public native int intMethod(int n);
	public native boolean booleanMethod(boolean bool);
	public native String stringMethod(String text);
	public native int intArrayMethod(int[] intArray);

	public static void main(String[] args)
	{
	System.loadLibrary("Sample1");

	#[
	This Nim source file is a multiple threaded implementation to perform an
	extremely fast Segmented Sieve of Zakiya (SSoZ) to find Twin Primes <= N.

	Inputs are single values N, or ranges N1 and N2, of 64-bits, 0 -- 2^64 - 1.
	Output is the number of twin primes <= N, or in range N1 to N2; the last
	twin prime value for the range; and the total time of execution.

	Code originally developed on a System76 laptop with an Intel I7 6700HQ cpu,
	2.6-3.5 GHz clock, with 8 threads, and 16GB of memory. Parameter tuning

	Red [
	Title: "Red Android bridge demo"
	Author: "Nenad Rakocevic"
	File: %eval2.red
	Config: [type: 'dll libRed?: no libRedRT?: yes export-ABI: 'cdecl]
	Tabs: 4
	Needs: 'View
	Rights: "Copyright (C) 2013-2017 Nenad Rakocevic. All rights reserved."
	License: {
	Distributed under the Boost Software License, Version 1.0.

	include karax / prelude
	import strutils

	type
	Model = object
	counter*: int
	Dispatch = proc(model: Model): void

	proc init(): Model =
	result = Model(counter: 0)