People seem to think that writing a garbage collector is really hard, a deep magic understood by a few great sages and Hans Boehm (et al) . Well it’s not. In fact, it’s rather straight forward. I claim that the hardest part in writing a GC is writing the memory allocator, which is as hard to write as it is to look up…
I’m often surprised that people continually have fundamental misconceptions about how distributed systems behave. I myself shared many of these misconceptions, so I try not to demean or dismiss but rather educate and enlighten, hopefully while sounding less preachy than that just did. I continue to learn only by…
Pinterest's tech stack explained simply
A solution to the problem of the growing number of mount points and loopback devices in (Ubuntu) Linux.
Wayland is all the rage those days. Distributions left and right switch to it, many readers of my previous article on writing a X11 GUI from scratch in x86_64 assembly asked for a follow-up article about Wayland, and I now run Wayland on my desktop. So here we go, let's write a (very simple) GUI program with Wayland…
Suppose you’re connected to a remote host with SSH and after a while the SSH session goes stale. The terminal is unresponsive and no keypress seem to take effect. There might be something with the network, the remote host is restarting or maybe your machine has been in hibernation, there could be multiple reasons for…
A dive into what x86 instruction are decoded into various processors, to determine the truth of the idea that they're just RISC-like internally.
How to have fun with the world’s most important free software project "Functional, free and secure by default", OpenBSD remains a crucial yet largely unacknowledged player in the open source field. This talk aims to highlight the project's signature security features and development practices -- razor sharp focus on…
The personal blog of Thomas Steiner
Yet another JDK release that is on track - JDK 20 GA is almost here . Another opportunity to summarize changes and improvements in Hotspot´s stop-the-world garbage collectors for the JDK 20 release.
Figuring out how much parallelism your program can use is surprisingly tricky.
This post is best described as a technology demonstration; it melds together web servers, plugins, WebAssembly, Go, Rust and ABIs. Here's what it shows:
Someone asked if I could write about the rise of AI and Large Language Models (LLMs) and what I think that means for the future of people, t...
In an era where the costs for cloud services continue to soar, I want to outline how our data team has successfully managed to run the infrastructure of our energy trading company within the first year using only two PostgreSQL database instances - each equipped with just two CPU cores and four GB of RAM. Despite this…
The Guardian is one of my favorite news sources. I’m a subscriber (support news organizations!) and I read it daily. But it is not immune to errors, as this headline shows:68 °F above average is a …
To be able to investigate and work on the the measured boot features I have switched from grub to systemd-boot (sd-boot).
Put an io_uring on it - Exploiting the Linux Kernel - chompie at the bits
Elixir supports the usual supects of observability. Open Telemetry (OTel), log handlers, capturing metrics. And it does it well. This post will mostly focus on the observability you have on the BEAM that is either incredibly rare to see elsewhere or possibly entirely unique.
macOS may alert you when you’re trying to open or run a file, with an alert informing you that malware was detected. But what about in scans?
Nearly all programs are written to access virtual memory addresses, which the CPU must translate to physical addresses. These translations are usually fast because the mappings are cached in the CPU's Translation Lookaside Buffer (TLB) . Unfortunately, virtual memory on x86 has used a 4 kiB page size since the 386 was…
You're probably reading this page because you've attempted to access some part of my blog (Wandering Thoughts) or CSpace , the wiki thing it's part of. Unfortunately you're using a browser version that my anti-crawler precautions consider suspicious, most often because it's too old (most often this applies to versions…
This post describes some performance work I have been doing recently on rustc. I spent several weeks on a particular problem with only a small amount of success. I hope a write-up will be interesting and educational, and may even lead to suggestions that make things better. The post is aimed at readers with some…
C++, a "Reality sandwich", and an Octopus.
I encountered the idea as a student, when I first read The Art of Computer Programming . I’d been programming already for most of my childhood, and I was completely blown away by the idea, which was entirely new to me. In fact, it’s probably not an exaggeration to say that in the whole of TAOCP that was the single…
Memory is a relatively scarce resource on many consumer computers, so a feature to limit how much memory a process uses seems like a good idea, and Microsoft did indeed implement such a feature. Ho…
As I was preparing the Windows NT RISC exhibit for VCF west , I realized that I’m missing a rather important piece of the history. While I was showing the potentially last DEC Alpha Windows build ever – AXP64 2210 , I don’t have anything earlier than NT 3.51. It would be nice to showcase the very first RTM version …
Differences between CloudKit and iCloud Drive, what each does, and how it works. New version of Cirrus to test and check iCloud function.
