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The State of Linux Security
This is the state of Linux security. With the most important updates around Linux and open source security. From conferences to self-protection.
Topics /
Systems & Performance
The most popular blog posts about systems & performance on Hacker News. 4,389 posts.
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Pumpkin OS: x64 port/re-implementation of PalmOS
Pumpkin is the name I have given to my port of PalmOS running on the x86 architecture. Please refer to this article for basic information on this project. Also look for other articles in the PalmOS…
2914
Using Zig to provide stack traces on kernel panic on bare metal (2018)
Last week, I reached an exciting milestone in my career as a programmer. For the first time in my life, I ran code directly on hardware , with no Operating System sitting between the bare metal and my code.
2915
How Not to Write a Signal Handler
This website is for sale! 741mhz.com is your first and best source for information about 741mhz. Here you will also find topics relating to issues of general interest. We hope you find what you are looking for!
2916
Galileo's Ground Segment Problem
The European Global Navigation Satellite System Galileo has recently been suffering from frequent "almost disruptions", most likely partially due to Corona, and possibly also due to Brexit, but in any case due to some historical stinginess. Before I explain what is going on, I should hasten to say that most days of…
2917
Qubes-Lite with KVM and Wayland
I've been running QubesOS as my main desktop since 2015. It provides good security, by running applications in different Xen VMs. However, it is also …
2918
Global Kernel Locks in APFS
Over the past several months, a handful of people had been complaining that Mercurial's test harness was executing much slower on Macs. But this slowdown seemingly wasn't occurring on Linux or Windows. And not every Mac user experienced the slowness!
2919
Working around dragons with the Lemote Yeeloong laptop and OpenBSD
Behold: the Guru of GNU ! (Photo by Habib Mhenni, Wikimedia Commons, CC BY-SA 3.0.) True enlightment only comes from a truly free computi...
2920
JVM Anatomy Quarks: Compressed References
"JVM Anatomy Quarks" is the on-going mini-post series, where every post is describing some elementary piece of knowledge about JVM. The name underlines the fact that the single post cannot be taken in isolation, and most pieces described here are going to readily interact with each other.
2921
FreeBSD now available on all EC2 instance types
I tried building FreeBSD AMIs for the 32-bit EC2 instance types the same way as I did the 64-bit instances — by defenestrating Windows AMIs — but there was a catch: They wouldn't boot. In fact, when I tried this six months ago, they not only didn't boot, but they didn't even produce any console output to help me…
2922
Mysql "Swap Insanity"
Update: Also read A brief update on NUMA and MySQL. The “swap insanity” problem, in brief When running MySQL on a large system (e.g., 64GB RAM and dual quad core CPUs) with a large Inno…
2923
Modern text rendering with Linux: Part 1
Introduction
2924
Writing a bare-metal RISC-V application in D
This post will show you how to use D to write a bare-metal “Hello world” program that targets the RISC-V QEMU simulator. In a future blog post ( now available ) we’ll build on this to target actual hardware: the VisionFive 2 SBC. See blog-code for the final code from this post. For a more complex example, see…
2925
RETRO is fast
When I first read Google’s RETRO paper, I was skeptical. Sure, RETRO models are 25x smaller than the competition, supposedly leading to HUGE savings in training and inference costs. But what about the new trillion token “retrieval database” they added to the architcture? Surely that must add back some computational…
2926
Cranelift, Part 2: Compiler Efficiency, CFGs, and a Branch Peephole Optimizer
This post is the second in a three-part series about Cranelift . In the first post , I described the context around Cranelift and our project to replace its backend code-generation infrastructure, and detailed the instruction-selection problem and how we solve it. The remaining two posts will be deep-dives into some…
2927
Memory-Level Parallelism: Intel Skylake versus Apple A12/A12X
Modern processors execute instructions in parallel in many different ways: multi-core parallelism is just one of them. In particular, processor cores can have several outstanding memory access requests "in flight". This is often described as "memory-level parallelism". You can measure the level of memory-level…
2928
Allocator Designs
This post explains how to implement heap allocators from scratch. It presents and discusses different allocator designs, including bump allocation, li…
2929
Blocking code is a leaky abstraction
Asynchronous code does not require the rest of your code to be asynchronous. I can’t say the same for blocking code.
2930
A timesyncd failure and systemd's lack of debugability
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…
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Beating the Compiler
An oft-repeated fact on programming forums these days is that a decent optimizing compiler will always beat a puny human's attempt at hand-written assembler. There are rare cases, like MPEG decoders, where making good use of the SIMD instructions can allow assembly to massively beat the compiler. But generally you'll…
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My favorite bug: segfaults in Java
Update: Two years later, I wrote a more detailed version of this article: My favorite bug: segfaults in Java (redux) .
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All GB/s without FLOPS – Nvidia CMP 170HX Review
This article contains a basic Nvidia CMP 170HX performance overview, a performance lockdown workaround, a hardware teardown, a watercooling installation guide, and a repair log.
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Rust in illumos
Systems engineering, Rust development, and Unix infrastructure by Till Wegmüller (@toasterson)
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NeXTSTEP on the HP 712 Part 1: Installation
It’s been a long time since my last pizzabox post - over a year! There’s been a lot going on in my life but I’m excited that lately I’ve had a lot more free time , which means more time to explore the world of workstations and share with you!
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Compiler Bugs Found When Porting Chromium to VC++ 2015
Moving a big software project to a new compiler can be a lot of work, and few projects are bigger than Chromium. In addition to the main Chromium repository, which includes all of Blink, there are …
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PostgreSQL 10: Partitions of partitions
PostgreSQL version 10 brings a much anticipated feature: (Native) Table Partitioning .
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NSCopyObject, the griefer that keeps on griefing
NSCopyObject is a very old Foundation function – pre-dating Mac OS X entirely; from the NeXT era – that was originally basically just memcpy , but now it’s complicated. A lot more complicated.