TeamTalk is a free and open-source multi-user conferencing system for Windows, Mac, Linux and mobile platforms, developed by Bjoern D. Rasmussen from Denmark. It allows user to perform real-time voice and video communication through Internet. For voice encoding, it uses the Opus and Speex audio codecs; for video streaming, it uses the WebM video codec.

WinSCP (short for Windows Secure Copy) is a free, open-source (S)FTP, WebDAV, Amazon S3 and SCP client for Windows, developed by Martin Přikryl from Czech Republic in 2000. It's mainly used to securely transfer files between local and remote computers, but it also provides features as a simple file manager and file synchronizer. In order to realize secure file transfer, it uses Secure Shell (SSH) to establish connections and provides support for SCP and SFTP (SSH File Transfer Protocol).

LOIC (short for Low Orbit Ion Cannon) is a free and open-source network/website stress testing tool initially developed by Praetox Technologies (currently maintained by the open source community) with C# in 2014. It's made for educational purposes only (that's to say, you should not use this software for illegal or unethical purposes, including activities that give rise to criminal or civil liability), and intended to help server owners develop a "hacker defense" attitude.

In the process of learning PCB design technology, many people may want to know what EDA design software is the most appropriate one? If it was several years ago, I would not hesitate to recommend Altium Designer to everyone. Because it was very popular, came with all kinds of supporting resources, and if you had any problem, you could always find someone familiar with this tool to ask for help. But today, KiCad has become a better choice.

Vagrant Story is my only one favorite video game (the originator of Dark Souls and Monster Hunter), I like it so much that I've long been preparing to recreate a simplified version of this game using Unity and Blender (just for fun and to implement the game design to my satisfaction). But the game's model building keeps standing in the way for me. After all, for a person who knows nothing about 3D modeling or drawing, it takes a lot of time and effort to reach a professional modeling level. Not to mention the later character action design, game system design, as well as many other aspects. Fortunately, I found Vagrant Story Tools.