Today I put online two diagrams depicting the architecture of the Unix operating system , one for the 1972 First Research Edition and one for FreeBSD, one of its direct descendants. Here are the details on how I created these diagrams.
Building your own UNIX shell in parts. This post focuses on the semantics of the fork system call.
Fully reproducible builds are important because they bridge the gap between auditable open source and convenient binary artifacts. Technologies like TUF and Binary Transparency provide accountability for what binaries are shipped to users, but that’s of limited utility if there is no way (short of reverse engineering)…
tl;dr: I make a petty point about premature optimization; don't go out and rewrite your switch statements as binary searches by hand; maybe do rewrite your jump tables as switch statements, though.
This is a recount of an adventure where I experimented with some Go assembly coding in trying to optimize the math.Atan2 function.
Wait-free algorithms attract vast interest and are an area of intense research, the motivation being that true lock-free algorithms and data structures provide great …
Our previous installment described the rise of automatic telephone switches, and of the complex relay circuits to control them. Now we shall see how scientists and engineers developed such relay c…
I am generally a fan of Go's approach to concurrency: writing code with goroutines is a lot easier than writing traditional nonblocking network servers in a language like C or C++. However, while working on a highly concurrent network proxy I came across an interesting realization about how the Go concurrency model…
This started out as a Hacker News comment about a blog post about select being fundamentally broken After that the same author wrote why epoll is broken as well. I don’t know what problem author is trying to solve but let’s pick this one:
This post is completely inspired by (or ‘copied from’ depending on your point of view) a recent post titled JAVA PAPERS (also see the HackerNews discussion). However, instead of looking at Java and the JVM, I’ll be looking at references to research papers in the .NET language, runtime and compiler source code.
Developers running their apps on tsuru can choose plans based on memory and cpu usage. We were looking at adding I/O usage as one of the plan’s features, so one could choose how many I/O operations per second or bytes per second a container may be able to read/write. Being able to limit I/O is particulary important…
Yet another programming blog. Thoughts on software and related misadventures.
tl;dr “Transparent Hugepages” is a Linux kernel feature intended to improve performance by making more efficient use of your processor’s memory-mapping hardware. It is enabled ("enabled=always") by default in most Linux distributions. Transparent Hugepages gives some applications a small performance improvement (~ 10%…
LZ4 is an exciting algorithm, but unfortunately there is no good explanation on how it works. This blog post tries to explain it in terms that everybody can understand.
Every week, Macs running High Sierra will check the integrity of their EFI firmware, in a bid to detect tampering by malware.
Do you love ("very") high-level languages? Like Lisp, Smalltalk, Python, Ruby? Or maybe Haskell, ML? I love high-level languages.
Absolute memory bandwidth figures tend to look fairly large, especially for GPUs. This is deceptive. It’s much more useful to relate memory bandwidth to say the number of clock cycles or inst…
The previous article Docker in Production: A History of Failure was quite a hit. After long discussions, hundreds of feedbacks, thousands of comments, meetings with various individuals and major pl…
Hello everyone! After many years of using a massively hacked-up version of dcoombs's NITLog page generator to host these pages, I've become,...
It is something we take for granted every time we run a .NET program, but it turns out that loading a Type or class is a fairly complex process.
Paul Khuong's personal blog. Some Lisp, some optimisation, mathematical or computer.
A backup-software developer's deep dive into Apple's APFS file system — snapshots, cloning, space sharing, and what it all means for reliable Mac backups.
I have moved off Medium to a personal blog. Click here for the updated post.
