Public Wi-Fi and some campus network typically block traffic from unauthenticated clients, but more often allow traffic targeting UDP port 53 to pass through, which is normally used for DNS queries...
Since my blog on installing Proxmox VE on eMMC, there’s been a lot of discussion over the Internet on this. I suspect that Proxmox decided not to include eMMCs in their hardware options by design, ...
Back in the days when the Zero COVID policy was prevailing, our university introduced a Daily Health Report system. Students and faculty were mandated to submit a daily online form detailing their ...
Advent of Code (Wikipedia, link) is an annual event that releases a programming puzzle every day from December 1 to December 25. It’s a great chance to learn a new language or practice your skills.
While a friend was building an automatic brewing pipeline, our Create: Astral server crashed and wouldn’t start again. At first we thought it’d be easy to restore our world from a backup, only to f...
Paper reading for [CIDR 2022] Are You Sure You Want to Use MMAP in Your Database Management System? by Crotty et al.
An LVM volume group (VG) on our Proxmox VE cluster has failed to create new logical volumes, reporting that its metadata was full. At first this appears to be easy, “fine I’ll just add more space f...
The 24 game is a classic math game where players try to arrange 4 integers into 24 using basic arithmetics (addition, subtraction, multiplication and division). Thanks to its popularity, it’s now a...
LDAP, the #1 way to get your graduation delayed (as has always been the meme around Tsinghua University), is every SysAdmin’s dream tool for their servers. As mighty as its rumors fly, LDAP takes t...
Recently I bought a mini PC looking forward to setting up a home router. It started quite well except the specs were higher than I anticipated. 8 GB RAM plus 128 GB eMMC - too much waste for “just ...
Linux 5.15 is shipped with a brand new driver for Microsoft’s classic NTFS filesystem, NTFS3. Unlike the decades-old open-source NTFS-3G project, which is based on FUSE and have always received cri...
This November I found a discount from one of my favorite VPS providers, NETfront. They offered Linux VPS with 2 vCPUs and 2 GB RAM at HK$56/mo, and also Windows VPS with 4 vCPUs and 4 GB RAM at HK$...
Linux has a built-in framework for Internet Protocol Security (IPsec), which is often combined with other tunneling technologies (e.g. L2TP and GRE) to create secure cross-site network connections....
Yesterday in a server maintenance period, we decided to tune the storage layout of our Proxmox VE server, which included disassembling a RAID 1 array and adjusting the size of the root filesystem.
Last year (maybe September? I don’t remember now) I switched my primary browser from Google Chrome to the new Microsoft Edge. It turned out to be a wise move and I’ve been with Edge for more than h...
Last month I set up my own Telegram bot for GitHub event notification. To receive GitHub events via webhook, a receiver is needed. True, it isn’t hard to write a Flask or Sinatra server and throw t...
Today when I was running some networking diagnostics from an Ubuntu inside VMware Workstation, I noticed this strange result from mtr (My Traceroute):
Since years ago, containers have been a hot topic everywhere. There are many container softwares like Docker, Linux Containers and Singularity. It’s hard to say one understand what containers are w...
It’s 2021 now, and Adobe Flash Player has been end-of-life after December 31, 2020. There are many cases where you want to retain it, however. For example, you may want to keep enjoying an old game...
Why use an external service when there’s an in-house GitHub service?
I’ll go straight to the solution (keep in mind that it’s considerably primitive, so use at your own risk) with code attached below. It’s a Tampermonkey userscript.
There’s a less-known feature of Jekyll that populates related_posts correctly with “related” posts, instead of the 10 latest posts when it’s disabled by default.
OpenSSH 8.2 is coming to the latest Long-Term Service release of Ubuntu, Focal Fossa (20.04), and has some breaking changes for users using an SSH Certificate Authority.
For all of us who are learning to use or developing with MySQL or MariaDB, it’s a common task to manually log in to the database for inspection. This is usually done with the mysql command line cli...
The 3rd-and-last experiment of course Web Information Processing and Application required us to create a recommendation engine, and “predict” the rating (1-5 stars) for 4M user-item pairs based on ...
Since the addition of the website server for an external corporation, I now have 5 Linux servers to manage on my own. I also have 4 terminal devices that I use to connect to those servers: two of m...
I recently retired a few old email addresses, and am currently going in a row to change email for accounts associated with those emails. Everything else went smoothly, with my Nvidia account being ...
This September I employed Cloudflare to optimize my website (https://ibugone.com) in various aspects. It turned out to be a brilliant move and Cloudflare has proved to be a great service to have.
This post originated from Lab 1 of course Compilers: Principles that I’m currently taking, in which we were required to write a flex program to parse a subset of the C language. The multiline comme...
Lately I’ve finally received my Raspberry Pi 4 (4 GB model), and I couldn’t resist the temptation to give it a try and see all the improvements that’s been reported for months.
This is a translated version from the Chinese (original) script. The slideshow can be acquired here. For comments, please head to the Chinese version of this post.
Last time I wrote an article about NAT traversal using FRP, which has been my personal solution for exposing SSH access of machines behind NAT to the internet for a long time.
A year ago back I wrote an article on automating build & deployment of GitHub Pages website with Travis CI. It’s a great CI service at first, but since Travis CI has completely moved away from ...
Earlier today I force-pushed to my repository USTC-RV-Chisel for testing purposes, without noticing that my local ref origin/master is 1 commit behind the actual master on GitHub. My friend pushed ...
This page provides:
Linux is the #1 open-source operating system nowadays, and many people are running a Linux distro, such as Ubuntu or Arch. Linux is also the most popular choice for a server OS.
It’s again when I want to find out what packages I have manually installed (or by a script) from the output of apt list, with all output on one line.
Have C or C++ project to build? You may think, “Yeah this is very easy, I’ll just call the compiler to do so”, and yes, let’s take a look at an example.
A quick step-by-step guide for those wanting to get in touch with Ubuntu in a virtual machine with minimal effort. For example, at the start of a semester of Operating System Concepts course.
Do you have a personal server at home but can’t access it from work or travel because your home doesn’t have a public IP? If so, then, this article is what you’re looking for.
This semester I have the course “Experiments of Digital Circuits”, the content of which is designing digital circuits using Vivado software, and writing Verilog code. Most of the lab papers require...
The TL:DR line: If you want my script, you can get it here.
I just bought an Xbox One S controller yesterday, expecting it would pair with my Android phone via Bluetooth. I have learned that the key mapping would be a bit messed up because it’s a Microsoft ...
How to create a Minimal, Complete, and Verifiable example
As described in a previous article, Alpha-Beta pruning can be used to speed up minimax heuristic searching by pruning branches that will never be reached.
As a casual attempt to accomplish a Grand Assignment, I created a Reversi game with Python. The project is open-source on GitHub and you can view it with the link above.
Update December 2020
After a plain request, an administrator of the SmokeDetector project added me under the Developers section of their team member list, which indicates that I am a known personnel for contributing a ...
std::string
For people new to template resolution and template type deduction in C++, they may have written this code and get confused why it doesn’t compile:
Laptops have usually at most four cores, and dualcores are probably more common. I have recently switched from quadcore to dualcore and I can confirm there is a limited number of use cases for quad...
Original post: RegEx match open tags except XHTML self-contained tags by bobince on Stack Overflow