build a small operating system from scratch, step by step. You might get intimidated when you hear OS or kernel development, the basic functions of an OS (especially the kernel) are surprisingly simple. Even Linux, which is often cited as a huge open-source software, was only 8,413 lines in version 0.01. Today’s Linux kernel is overwhelmingly large, but it started with a tiny codebase, just like your hobby project. We’ll implement basic context switching, paging, user mode, a command-line shell, a disk device driver, and file read/write operations in C. Sounds like a lot, however, it’s only 1,000 lines of code!

So without further ado, I present to you … Regex Chess: sequence of 84,688 regular expressions that, when executed in order, will play a (valid; not entirely terrible) move given a chess board as input.

Working in large established codebases is one of the hardest things to learn as a software engineer. You can’t practice it beforehand (no, open source does not give you the same experience). Personal projects can never teach you how to do it, because they’re necessarily small and from-scratch.

People, myself included, like to say that POSIX time, also known as Unix time, is the number of seconds since the Unix epoch, which was 1970-01-01 at 00:00:00. This is not true. Or rather, it isn’t true in the sense most people think. For example, it is presently 2024-12-25 at 18:51:26 UTC. The POSIX time is 1735152686. It has been 1735152713 seconds since the POSIX epoch. The POSIX time number is twenty-seven seconds lower.

How 2 devices under a NAT can connect directly to each other without a server beind in the middle to relay traffic?

Routing table define what what happens when an IP packet is sent from or through a Linux box. But the simplify is which destination a package should send to? how do your computer know that a LAN ip need to send to othe laptop, and the rest go out to internet?

When you need memory for your program, you can malloc. Similarly to malloc, a pool allocator allows the user to allocate memory at run time. The pool allocator, however, is much faster than malloc1, at the cost of having a fixed pool size. It allows the user to allocate and free memory blocks (referred to as chunks, from now on) in O(1) constant time. This implementation also uses very little memory: when creating the pool, a very small Pool structure is allocated, along with the pool itself. Free chunks are used to store information, so the memory impact is minimal.

Stream Live accepts audio/video content from broadcasters and makes that content available to viewers around the world in real time through the Cloudflare network. This post look into how they build broadcast ingestion with RTMPS, SRT, WHIP and Spectrum. The data is converted and store in their Durable Object, then serve to viewer through HLS or DASH protocol.

B-Trees were essentially “better” Binary Search Trees, with some hand-waving done that they had improved performance when used in database applications. But it’s more than just that, today we will look into disk constraint, slotted pages to see how B-Tree node fit naturally into a page - a chunk of data that the harddrive read all in the same time.

Arrays are in every web developer’s toolbox, and there are a dozen ways to iterate over them. Choose wrong, though, and all of that processing time will happen synchronously in one long, blocking task. The thing is, the most natural ways are the wrong ways.