Andrey Petrov shazow

Falsehoods that Ethereum programmers believe

I recently stumbled upon Falsehoods programmers believe about time zones, which got a good laugh out of me. It reminded me of other great lists of falsehoods, such as about names or time, and made me look for an equivalent for Ethereum. Having found none, here is my humble contribution to this set.

About Gas

Calling `estimateGas` will return the gas required by my transaction

Calling estimateGas will return the gas that your transaction would require if it were mined now. The current state of the chain may be very different to the state in which your tx will get mined. So when your tx i

hardware/software

Webcam parts:

Raspberry Pi Zero W Rev 1.1
Raspberry Pi Camera v2 (8-megapixel)
Raspberry Pi High Quality Camera (12.3-megapixel)
Raspbian Buster Lite 2020-02-13

Webcam works with:

Windows 10
Windows 10 "Camera" app

Synology/wg

To avoid some bugs in wg-quick and/or iptables on my Synology:

I set up the wireguard device manually.
I used network namespaces to create an explicit tunnel namespace. I then specified DNS for this namespace only.

Credit where credit is due. I got this idea from the Wireguard website. https://www.wireguard.com/netns/#the-new-namespace-solution

VFIO Setup on NixOS

Disclaimer: Nobody else tested my setup so far, so this is a "works on my machine" scenario. I am not responsible for anything you break on your machine (although I'd not expect much harm).

Hardware

My system has the following hardware:

Board: ASRock X570 Pro4

Do I want to die on this hill?

Pass: This is morally good and if not handled has long term consequences
Fail: This if self serving

Am I including everyone?

Pass: My ego is not driving this conversation
Fail: The people in this conversation will only tell me I'm right and not push back

Freezer cgroup FTW

In a terminal start a server.

$ python -m SimpleHTTPServer 8000

In another terminal set up the cgroups freezer.

	with import <nixpkgs> {};
	let
	my-python-packages = python-packages: with python-packages; [
	pip
	setuptools
	];

	python-with-my-packages = pkgs.python3.withPackages my-python-packages;

	# define packages to install with special handling for OSX

	package main

	import (
	"flag"
	"image"
	"image/color"
	"time"

	"github.com/peterhellberg/gfx"
	)

	#!/usr/bin/python3

	from bluepy import btle
	import sys

	class DiscoLH(btle.DefaultDelegate):

	def __init__(self):
	self.devices = []
	btle.DefaultDelegate.__init__(self)

	package main

	import (
	"bytes"
	"crypto/rand"
	"math/big"
	"strings"

	"github.com/ethereum/go-ethereum/accounts/abi"
	"github.com/ethereum/go-ethereum/common"