andy digitalsignalperson

XFS reflinks vs BTRFS snapshots

reflinks in XFS

reflinks can be used as CoW mechanism for XFS since 4.17.0-2.el8

This feature enables two or more files to share a common set of data blocks. When either of the files sharing common blocks changes, XFS breaks the link to common blocks and creates a new file.

so with cp --reflink we can create CoW blocks already. This is similar to btrfs CoW. We can simply do following to mimic the snapshot:

find /root -mindepth 1 -maxdepth 1 -not -name "backup" -exec cp -r --reflink {} /root/backup/$(date)/ ;

Goal

How to launch multiple QEMU based VM's that can communicate with the outside world and between each other other without any setup on the host.

This uses two features available in qemu

User Mode Networking stack - SLIRP
Socket networking backend allows you to create a network of guests that can see each other

This allows us to have

	#!/usr/bin/env python3
	"""
	Dynamic and Adaptive Python Environment in a Bubblewrap Sandbox

	Overview:
	This project demonstrates a minimal, safe, and self-contained Python execution
	environment using bubblewrap (bwrap) and uv. The goal is to provide a lightweight
	alternative to Docker for running agent code—in this case, dynamically generated
	Python code along with its dependencies—within an isolated sandbox.

	#!/bin/bash

	SERVICE="org.kde.KWin"
	DBUS_PATH="/org/kde/KWin/InputDevice"
	INTERFACE="org.kde.KWin.InputDevice"
	METHOD_GET="org.freedesktop.DBus.Properties.Get"
	METHOD_SET="org.freedesktop.DBus.Properties.Set"

	function find_touchpad {
	DM_INTERFACE="org.kde.KWin.InputDeviceManager"

	import matplotlib.pyplot as plt

	def move_axes(ax, fig, subplot_spec=111):
	"""Move an Axes object from a figure to a new pyplot managed Figure in
	the specified subplot."""

	# get a reference to the old figure context so we can release it
	old_fig = ax.figure

	# remove the Axes from it's original Figure context

	#define CONCAT_2_EXPAND(A, B) A ## B
	#define CONCAT_2(A, B) CONCAT_2_EXPAND(A, B)
	#define CONCAT_3_EXPAND(A, B, C) A ## B ## C
	#define CONCAT_3(A, B, C) CONCAT_3_EXPAND(A, B, C)

	#define Vector_(NAME) CONCAT_3(Num, Vector_, NAME)
	#define Vector CONCAT_2(Num, Vector)

	#define num float
	#define Num Float