My automated Daily Health Report infrastructure
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 ...
2023
Overengineering Advent of Code 2022
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.
2022
Recovering a Minecraft world from a crash, the technician way
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: Are You Sure You Want to Use MMAP in Your Database Management System?
Paper reading for [CIDR 2022] Are You Sure You Want to Use MMAP in Your Database Management System? by Crotty et al.
LVM metadata exceeds maximum metadata size, now what next?
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...
Taking the 24 puzzle game to the next level
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...
Centralized Linux authentication with OpenLDAP
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...
Install Proxmox VE on eMMC
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 ...
2021
New Pandora’s box: Install Linux and Windows onto the same NTFS partition
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...
Reinstall Windows VPS into Linux with iPXE network boot
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$56/mo, and also Windows VPS with 4 vCPUs and 4 GB RAM at HK$...
Secure site-to-site connection with Linux IPsec VPN
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....
Disassembling a hardware RAID 1 array in Proxmox VE
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.
I switched from Google Chrome to Microsoft Edge
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...
Setting up a GitHub webhook on AWS Lambda
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...
Fix traceroute not showing intermediate results in a virtual machine on Windows
Today when I was running some networking diagnostics from an Ubuntu inside VMware Workstation, I noticed this strange result from mtr (My Traceroute):
A Deep Dive into Containers
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...
Keep using Flash Player in browsers in 2021
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...
2020
Build GitHub Pages with GitHub Actions
Why use an external service when there’s an in-house GitHub service?
Working against WordPress DeBlocker plugin
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.
Enabling better “Related Posts” with Jekyll
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.
Use RSA CA Certificates with OpenSSH 8.2
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.
3 ways to use MySQL / MariaDB CLI without password
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...
2019
High-performance mass web crawling on AWS
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 ...
Managing servers with OpenSSH Certificate Authority
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...
How to change email of your Nvidia account
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 ...
Make your GitHub Pages website faster with Cloudflare
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.
Converting DFA to Regular Expression
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...
Raspberry Pi 4 B Review and Benchmark - What’s improved over Pi 3 B+
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.
My speech at Microsoft Summer Camp 2019
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.
Creating templated Systemd services
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.
Using SSH deploy keys on CircleCI
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 ...
How I saved a lost commit from GitHub
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 ...
Wolfram Mathematica 13 Key Generator Online
This page provides:
Build a minimal Linux system and run it in QEMU
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.
Filter manually installed packages from APT with AWK
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.
Bootstrapping Make
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.
Setting up Ubuntu in VMware Workstation
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.
Access your Raspberry Pi remotely with SSH
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.
2018
Programming the On-Board SPI Flash of Digilent Nexys4 DDR
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...
Batch convert PowerPoint slideshow to PDF
The TL:DR line: If you want my script, you can get it here.
Pairing the new Xbox One S controller (2018) with Android
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 ...
Minimal, Complete, Verifiable Example
How to create a Minimal, Complete, and Verifiable example
Alpha-Beta Pruning
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.
Making a Reversi game with Python
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.
Build GitHub Pages with Travis CI
Update December 2020
Joining SmokeDetector
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 ...
2017
Append int to 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:
Some ideas about multicore on Android
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...
2009
RegEx match open tags except XHTML self-contained tags
Original post: RegEx match open tags except XHTML self-contained tags by bobince on Stack Overflow