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The most popular blog posts about systems & performance on Hacker News. 340 posts.
FreeBSD 15 comes with a new bridging implementation which has native support for VLANs. They have also soft-deprecated the ability to have any layer 3 addresses on member interfaces which makes it behave like a real hardware switch. The net.link.bridge.member_ifaddrs sysctl controls this behavior and it will …
An new old approach to emulation.
Compilers have a hard time optimizing floating point math. Rust has a new API to fix this.
So I was optimizing a domain-specific compressor the other day, as one does. One important problem was chunking the input string and optimally choosing the most compact encoding for each chunk (different encodings compress different characters better, so where to split is not immediately obvious). The previous post…
Last year I've fixed a bug in Linux kernel OHCI (USB 1.1) stack , which rendered my old printer unreliable: OHCI adds artificial delay of 1ms for each USB transfer of send-read pattern, while my very old, host-based printer expects very tight timings and constant latency, like some kind of CnC machine.
The memory management in DOS is simple, but that simplicity may be deceptive. There are several rather interesting pitfalls that programming documentation often does not mention.
Back in January, the ThunderScope team sent me a PCIe card version of their prototype open hardware oscilloscope.
I’ve been experimenting with different approaches to running code in a sandbox for several years now, but my latest attempt feels like it might finally have all of the characteristics …
In 1978, Intel introduced the 8086 processor, a revolutionary chip that led to the modern x86 architecture. Unlike modern 64-bit processors,...
The personal blog of Pig Fang.
Update (28th of September 2026) Max Desiatov told me that the @c swift attribute should work, instead of declaring the functions using @_cdecl. The @c attribute marks a global function as a C function implemented in Swift, which formalizes the @_cdecl attribute. A link to the proposal is available here. I did update…
ABSTRACT In May 2003, the University of Wisconsin - Madison found that it was the recipient of a continuous large scale flood of inbound Internet traffic destined for one of the campus' public Network Time Protocol (NTP) servers. The flood traffic rate was hundreds-of-thousands of packets-per-second, and hundreds of…
One little step toward UNIX
Root election, port roles, proposals and agreements, topology changes: explore RSTP through simulations powered by MSTPD compiled to WebAssembly.
I've recently tasted AMD Zen 5 CPUs (AWS' m8a instances) and... Whooaaa. Even before talking about GPUs and NPUs, the next 5 years of CPUs will be very exciting! For
2026 legacy lab summer camp plan
Learn what a unikernel is and how it compares to a Linux container. Build and run your first unikernel inside a playground box.
How good is the random_page_cost default, and should you lower it on modern flash storage?
As is typical here in the Floodgap lab, it all started so innocently: rebuilding a flaky Apple Workgroup Server 9150, the odd duck of the Wo...
Goodbye dangling Dupont pins, hello Julet E-Bike connector. I have them now everywhere, from my router to my servers.
While I’m taking a short break from low-level programming, here’s a story by a friend of mine, Sonya, about debugging a seemingly impossible bug in ARM code. This bug hunting saga started several months ago. While developing a bare-metal hypervisor on ARM64 for postmarketOS, I hit a strange bug: if I enabled the…
If you don’t want any of their services, you can turn Siri off in its settings, and disable indexing and search in Spotlight settings. Or you can use mdutil, if you know its limitations.
A single-producer single-consumer (SPSC) queue is a great example of how far constraints can take a design. In this post, you will learn how to implement a ring …
The cost of thread context switch, including cache invalidation, can reach up to 3 million CPU cycles RTTI can be quite expensive, with dynamic_cast being up...
My thoughts on why enterprise knowledge systems have failed for sixty years, and what might finally replace them. A couple of weeks ago I demoed one part of what I have been building to a senior exec at a global enterprise - someone who had been asked to lead and guide
Do you feel spoiled by modern hardware? I know I do. Even the cheapest CPUs have at least 4 cores nowadays, running billions of operations per second. The idea that you could run any software on le…
A guide to bringing up the Linux Kernel and a userspace application on a new hardware (or in this case, a self-made emulator)
I've been moving my home storage over to a UniFi UNAS Pro 8 as part of a larger ...
