Posts that commenters keep linking to, ranked by how many different people have cited them in Hacker News comments. 696 posts.
About three years ago I wrote an article analyzing the memory usage of arrays in PHP 5. As part of the work on the upcoming PHP 7, large parts of the Zend Engine have been rewritten with a focus on smaller data structures requiring fewer allocations. In this article I will provide an overview of the new hashtable…
For almost two decades, MSKey Readme 1 has heralded the defeat of Windows XP's product activation, not via mere circumvention , but by cracking the encryption algorithm itself.
First, I want to make it clear that I’m not accusing the compositor of true evil, which I define roughly as deliberately causing suffering. There’s unfortunately too much of that in the world. I mean it in the more metaphorical sense that it causes serious problems and forces other parts of the system to be more…
When writing networked games, the question of UDP vs TCP will eventually come up. Typically you will hear people say things like: “Unless you’re doing action games, you can use TCP̶…
The previous post described [motherboards and the memory map] memory-map in Intel computers to set the scene for the initial phases of boot. Booting is an involved, hacky, multi-stage affair - fun st
There has been much discussion of using the Rust language in the Linux kernel (for example, here , here , and here ), at the Kangrejos Rust for Linux Workshop ( here , here , and here ) and 2021 Linux Plumbers Conference had a number of sessions on this topic, as did Maintainers Summit . At least…
Why developers rarely use state machines, seeing them as overkill until it's too late to switch, and what the state_machine gem did for CrowdHired.
Ncdu (NCurses Disk Usage) is a terminal-based disk usage analyzer for Linux and other POSIX-y systems, (formerly) written in C and available in the package repositories of most distributions.
It is difficult to write software which reliably and safely manages processes on Unix; this is because of flaws in the API. I know of no Unix system which has solved these problems, but in this article I'll be specifically talking about the Linux process API.
After running this command, PID 1 is hung in the pause system call. You can no longer start and stop daemons. inetd-style services no longer accept connections. You cannot cleanly reboot the system. The system feels generally unstable (e.g. ssh and su hang for 30 seconds since systemd is now integrated with the login…
AVAILABLE NOW OpenAI, Anthropic, and Chrome ship it. Apple deprecated it. Nobody documented it. Until now. → sandbox-exec: The Miss...
As an engineer who primarily works with data and databases I spend a lot of time moving data around, hashing it, compressing it, decompressing it and generally trying to shovel it between VMs and blob stores over TLS. I am constantly surprised by how many systems only support slow, inefficient, and expensive ways of…
In the past few weeks, I reviewed USB drive performance on the Raspberry Pi 4, and the importance of UASP support for USB drive performance. Both posts generated great discussion, and there were three things I wanted to cover in this follow-up, namely: Which drives support UASP Real-world performance benchmarks TRIM…
SQLite is an embedded SQL database. It’s extremely easy to setup, buildable as a single C file with libraries existing for basically all common programming languages. It doesn’t need any server setup or configuration since the SQL logic is run in the host process, and the database consists of only
You only need to learn a little bit of queueing theory before you start getting that ecstatic “everything is connected!” high that good math always evokes. So many damn things follow th…
The `ldd` utility is more vulnerable than you think. It's frequently used by programmers and system administrators to determine the dynamic library dependencies of executables. Sounds pretty innocent, right? Wrong! In this article I am going to show you how to create an executable that runs arbitrary code if it's...
AWK As A Major Systems Programming Language — Revisited
Performance budgets are an essential but under-appreciated part of product success and team health. Most partners we work with are not aware of the real-world operating environment and make inappropriate technology choices as a result. We set a time budget of less than 5 seconds first-load Time-to-Interactive and less…
Firmware flash Samsung SSD or NVMe directly from Linux without needing broken Samsung ISO boot environment!
I worked on Rust part-time for several years at Mozilla. During that period I regularly summarized how the compiler’s performance had improved. For example: 2017-11-12 to 2019-07-24.
By that I mean a delay between receiving movement data from the mouse device and rendering the on-screen cursor. The lag of a Mac OS X cursor is at least twice bigger than Windows’ cursor and yes, a human eye can surely notice that.
"Emails show [Chris Cristie]'s aides did plan bridge gridlock," says Salon . To a transportation engineer, the aides are innocent: bridges can't have gridlock. While we often say "gridlock" to mean "bad traffic," it has a technical meaning.
Not all instructions on modern processors cost the same. Additions and subtractions are cheaper than multiplications which are themselves cheaper than divisions. For this reason, compilers frequently replace division instructions by multiplications. Roughly speaking, it works in this manner. Suppose that you want to…
