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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:

Enable PipeWire on Ubuntu 22.04

This guide is only for original Ubuntu out-of-the-box packages. If you have added a custom PPA like pipewire-debian, you might get into conflicts.

Ubuntu 22.04 has PipeWire partially installed and enabled as it's used by browsers (WebRTC) for recoding the screeen under Wayland. We can enable remaining parts and use PipeWire for audio and Bluetooth instead of PulseAudio.

Starting from WirePlumber version 0.4.8 automatic Bluetooth profile switching (e.g. switching from A2DP to HSP/HFP when an application needs microphone access) is supported. Jammy (22.04) repos provide exactly version 0.4.8. So, we're good.

Based on Debian Wiki, but simplified for Ubuntu 22.04.

Half-baked thoughts exploring a different way of implementing a fully-validating BCH node.

The idea is to shift the storage of full transaction data to wallets, and explore how little data a fully validating node could store. This isn't a problem today (the UTXO set easily fits in the RAM of an inexpensive server-class machine), but might eventually be at very large transaction volumes.

Initial block download is a problem today (it is annoying to have to wait several hours or days to sync up a new node), and this scheme could make it orders of magnitude faster by shifting the time when full transaction data is broadcast from initial block download to new transaction announcement.

Quick Tips for Fast Code on the JVM

I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.

This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea

gRPC Best Practice @ CoreOSFest 2017

https://coreosfest2017.sched.com/event/AWYc/best-practices-for-go-grpc-services-doug-fawley-google

Just small note for me. Hope the slide will be opened.

API design
- Idmpotency
  - It should be safe to retry an RPC without knowing whether it was processed
Example

The following example demonstrates the creation of a raw Omni transaction, which transfers 0.1 Test Omni with token identifier 2 from 1K6JtSvrHtyFmxdtGZyZEF7ydytTGqasNc to 1Njbpr7EkLA1R8ag8bjRN7oks7nv5wUn3o, with a transaction fee of 0.0006 BTC. For the sake of a demonstration, more than one unspent output was consumed.

1) List unspent outputs

List unspent outputs for 1K6JtSvrHtyFmxdtGZyZEF7ydytTGqasNc.

omnicore-cli "listunspent" 0 999999 '["1K6JtSvrHtyFmxdtGZyZEF7ydytTGqasNc"]'

	/* Changes the readable line length in Obsidian Notes. Tested in Obsidian v1.0.0
	See https://gist.github.com/vii33/f2c3a85b64023cefa9df6420730c7531/f4ea845b240e94c9fcd47d456340f78208dab38f
	*/

	body {
	--file-line-width: 750px;
	}

	#!/bin/sh
	# Minimal tmux script to create a master dcrd simnet node + ticket
	# bying wallet. Heavily based on davecgh script at:
	# https://gist.github.com/davecgh/7bb5c995665787811dc6a6ddbb49688d

	set -e

	SESSION="dcrd-fees"
	NODES_ROOT=~/dcrdsimnetnodes
	RPCUSER="USER"

	const bitcoin = require('bitcoinjs-lib') // version @3.3.2, ver4 won't work
	const request = require('request-promise-native')
	const net = process.env.NETWORK === 'testnet'
	? bitcoin.networks.testnet
	: bitcoin.networks.bitcoin

	const API = net === bitcoin.networks.testnet
	? `https://test-insight.swap.online/insight-api`
	: `https://insight.bitpay.com/api`

	#!/bin/sh

	set -e

	SIMNET_NODES_ROOT=~/dcrdsimnetnodes
	MASTERNODE_ADDR=127.0.0.1:19555
	NODE1_ADDR=127.0.0.1:19501
	NODE2_ADDR=127.0.0.1:19502
	NODE3_ADDR=127.0.0.1:19503
	NODE4_ADDR=127.0.0.1:19504