Those of you who haven’t been in IT for far, far too long might not know that next month will be the 16th(!) anniversary of the disclosure of what was, at the time, a fairly earth-shattering revelation: that for about 18 months, the Debian OpenSSL package was generating entirely predictable private keys .
I have recently done some performance work and realized that reading about my experience could be entertaining. Teaching to think is just as important as teaching to code, but this is seldom done; I think something I’ve done last month is a great opportunity to draw the curtain a bit. serde is the Rust framework for…
The slides, the video, and the text behind my presentation at EuroBSDCon 2024 and BSDCan 2025 - Why and how we're migrating many of our servers from Linux to the BSDs.
Learn the microarchitecture-level details of the processor that enable to execute two threads at the same time on a CPU core
An old document I surfaced with my quick tour of distributed systems theory fundamentals
I have been tinkering with the vanilla source code of Wolfenstein 3D from 1992. Even though it is more than 20 years old and has rotten for modern systems, you can still compile it if you recreate the environment. All you need is :
How a modern AVX instruction shares a similar design with a 1985 blitter chip, by Arnaud Carré
This article explains the mechanics behind traceroute, from IP headers and TTL fields to ICMP messages. Learn why traceroute is a crucial tool for network diagnostics, how it differs from ping, and how to interpret its output. Ideal for network administrators, IT professionals, and curious users looking to understand…
We're going to speed up some numpy code by 100x using "unsafe Python." Which is not quite the same as unsafe Rust, but it's a bit similar, and I'm not sure what else to call it... you'll see. It's not something you'd use in most Python code, but it's handy on occasion, and I think it shows "the nature of Python” from…
The Championnats d’Europe d’Escalade (climbing) in Villars-sur-Ollon has just finished. I couldn’t make it to all the events, but did see the finals of the “Speed” event. It’s a series of head-to-head elimination races up a 15m tall wall, resulting in an eventual victor after enough rounds.
A Pretty Map of the European Power Grid
Memory-Dump-UEFI is a UEFI application for dumping the contents of RAM.
Structuring a large program is always a difficult job. One of the particular problems that often comes up is this: if you have a piece of code producing data, and another piece of code consuming it, which should be the caller and which should be the callee?
Hubris's oddest syscall
This is not at all news, but it comes up often enough that I think there should be a concise explanation of the problem. 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.
Preface In October 2023 I learned about HTTP/2 Rapid Reset attack, dubbed “the largest DDoS attack to date”. I didn’t have deep knowledge of HTTP/2 back then. I knew its basics like frames or HPACK but I was focusing more on HTTP/1.1 protocol and programming languages vulnerabilities. I decided to dedicate time to…
The Ivory Tower is a blog about software engineering and development philosophy by Anders Sundman.
Often when I’m prototyping a project, I hesitate to use a sqlite database despite their many adavantages . It seems much easier to just dump a bunch of files in a directory and to rely on the universal support for the filesystem API to read/delete/update records. Part of this is avoiding the overhead of figuring out a…
The first article in a series where I explore aspects of systemd by creating small examples with the help of containers.
Kenton Varda introduces the next iteration of Cloudflare's Durable Object platform, which recently upgraded from a key/value store to a full relational system based on SQLite. For useful background on …
An overview of erasure coding, its trade-offs, and applications in distributed storage systems.
I recently implemented a small program to visualize the inner workings of a scheme that compresses floating point timeseries by XORing subsequent values. The resulting visualizations are quite neat…
By Ruben Schade in Eora/Sydney, Australia.
If a value mutates in the forest with no one to see it, does it really mutate?
A couple of years ago I wrote about tolower() in bulk at speed using SWAR tricks . A couple of days ago I was interested by Olivier Giniaux’s article about unsafe read beyond of death , an optimization for handling small strings with SIMD instructions, for a fast hash function written in Rust.
