donaldh.wtf

Ethernet Driver Features in 7.1

Mon, 15 Jun 2026 08:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 7.1.

Tuscan Resurrection

Tue, 05 May 2026 11:47:06 +0100

Dusting off the TVR and giving it a much needed overhaul to make it roadworthy again.

Ethernet Driver Features in 7.0

Mon, 20 Apr 2026 08:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 7.0.

Ethernet Driver Features in 6.19

Mon, 09 Feb 2026 08:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.19.

2025 AoC Day 12 – Christmas Tree Farm

Fri, 12 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 12, written in Raku.

2025 AoC Day 11 – Reactor

Thu, 11 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 11, written in Raku.

2025 AoC Day 10 – Factory

Wed, 10 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 10, written in Raku.

2025 AoC Day 9 – Movie Theater

Tue, 09 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 9, written in Raku.

2025 AoC Day 8 – Playground

Mon, 08 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 8, written in Raku.

2025 AoC Day 7 – Laboratories

Sun, 07 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 7, written in Raku.

2025 AoC Day 6 – Trash Compactor

Sat, 06 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 6, written in Raku.

2025 AoC Day 5 – Cafeteria

Fri, 05 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 5, written in Raku.

2025 AoC Day 4 – Printing Department

Thu, 04 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 4, written in Raku.

2025 AoC Day 3 – Lobby

Wed, 03 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 3, written in Raku.

2025 AoC Day 2 – Gift Shop

Tue, 02 Dec 2025 00:00:00 +0000

This is a solution to Advent of Code 2025 day 2, written in Raku.

2025 AoC Day 1 – Secret Entrance

Mon, 01 Dec 2025 10:00:00 +0000

This is a solution to Advent of Code 2025 day 1, written in Raku.

Ethernet Driver Features in 6.18

Mon, 01 Dec 2025 08:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.18.

An Ode to Org Babel

Thu, 27 Nov 2025 17:00:00 +0100

Org mode is an Emacs major mode with a laundry-list of powerful features, one of which is Org Babel, the literate programming engine that is embedded within Org mode. Think of it as the polyglot jupyter notebook of Emacs, if you will.

Emacs Carnival 2025-11 — An Ode to Org Babel

Fri, 31 Oct 2025 10:30:00 +0000

The topic for this month's Emacs Carnival is An ode to Org Babel and is an opportunity to shine a light on the literate programming engine embedded in Org mode.

Ethernet Driver Features in 6.17

Sun, 05 Oct 2025 08:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.17.

Packet SKB drops four ways

Sat, 27 Sep 2025 17:30:00 +0100

Demonstrating 4 nifty ways that bpftrace can be used to report SKB drops in the Linux kernel networking data path.

A minimal config for Emacs on macOS

Sun, 21 Sep 2025 22:00:00 +0100

This is a somewhat opinionated minimal set of customisations for Emacs when running on macOS that give me a good baseline quality of experience.

Pasting Images in Org Mode

Sun, 17 Aug 2025 22:01:07 +0100

Streamlining image capture while blogging in Emacs.

Ethernet Driver Features in 6.16

Sat, 09 Aug 2025 08:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.16.

TIL – Emacs display-buffer-alist

Fri, 08 Aug 2025 10:00:00 +0100

TIL that I can use display-buffer-alist to define a custom placement behaviour for specific buffers.

about donaldh

Sun, 06 Jul 2025 00:00:00 +0000

A veteran software engineer working at Red Hat where I explore and evangelise emerging technologies, with a focus on all things security.

I am currently the Security Team Lead in the Office of the CTO, Emerging Technologies team.

I write articles for the Red Hat Developer blog when I can:

I am a maintainer of the YNL library and Netlink specifications that live in the Linux kernel git repository.

what I'm doing now

Sun, 06 Jul 2025 00:00:00 +0000

This Week

Workwise, I am deep in planning for the second half of the year. For recreation I am hoping to learn a bunch from Alice's Adventures in a Differentiable Wonderland.

Recently

I have been getting a lot of mileage out of using Gemini for research and Claude Sonnet for AI pair programming. Currently a bit of a fan of Aider and aidermacs for my vibe coding needs.

I am test driving git-delta for prettified side-by-side diffs on the git command line.

TIL - M-y runs yank-from-kill-ring

Sun, 29 Jun 2025 17:15:00 +0100

TIL that M-y runs yank-from-kill-ring if used after any other command than a yank. Amazed that I have used Emacs for decades without learning this.

Ethernet Driver Features in 6.15

Mon, 26 May 2025 08:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.15.

Emacs Nested Projects Redux

Wed, 21 May 2025 09:00:00 +0100

Emacs performance problems in python-mode when using project-rootfile and TRAMP. Updated on May 24, 2025 to wrap up the saga.

Ethernet Driver Features in 6.14

Tue, 25 Mar 2025 08:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.14.

Nested projects in Eglot

Fri, 07 Mar 2025 14:00:00 +0000

Figuring out how to make Eglot work with nested projects in Emacs. Updated on May 24, 2025 to steer people towards project-vc-extra-root-markers instead.

Kernel development in Emacs

Wed, 26 Feb 2025 08:30:00 +0000

A quick rundown of how I do Linux kernel development in Emacs.

TIL – Magit References Buffer

Sun, 23 Feb 2025 21:27:01 +0000

Discovering the Magit references buffer that has been hiding in plain sight.

Eglot Hover Performance

Fri, 21 Feb 2025 16:20:24 +0000

Investigating an issue where Emacs freezes when viewing some Linux kernel source files.

Ethernet Driver Features in 6.13

Fri, 31 Jan 2025 09:00:00 +0000

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.13.

2024 AoC Day 12 – Garden Groups

Thu, 12 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 12, written in Raku.

2024 AoC Day 11 – Plutonian Pebbles

Wed, 11 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 11, written in Raku.

2024 AoC Day 10 – Hoof It

Tue, 10 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 10, written in Raku.

2024 AoC Day 9 – Disk Fragmenter

Mon, 09 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2023 day 9, written in Raku.

2024 AoC Day 7 – Bridge Repair

Sat, 07 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 7, written in Raku.

2024 AoC Day 6 – Guard Gallivant

Fri, 06 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 6, written in Raku.

2024 AoC Day 5 – Print Queue

Thu, 05 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 5, written in Raku.

2024 AoC Day 4 – Ceres Search

Wed, 04 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 4, written in Raku.

2024 AoC Day 3 – Mull It Over

Tue, 03 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 3, written in Raku.

2024 AoC Day 2 – Red-Nosed Reports

Mon, 02 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 2, written in Raku.

2024 AoC Day 1 – Historian Hysteria

Sun, 01 Dec 2024 00:00:00 +0000

This is a solution to Advent of Code 2024 day 1, written in Raku and in Rust.

Lower Other Frame in Emacs

Tue, 19 Nov 2024 23:30:54 +0000

Extending ace-window to lower a chosen frame.

Ethernet Driver Features in 6.12

Mon, 18 Nov 2024 10:00:00 +0100

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.12.

Ethernet Driver Features in 6.11

Mon, 23 Sep 2024 10:00:00 +0100

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.11.

Keyboard Mods Redux

Fri, 16 Aug 2024 18:53:14 +0100

Adding an RGB layer to my QMK keyboard to declutter the fn layer.

Keyboard Week Two

Mon, 29 Jul 2024 23:06:11 +0100

Diving into keyboard customisation with QMK.

Nature

Sun, 28 Jul 2024 23:00:00 +0100

A photo diary of nature winning.

A New Keyboard

Wed, 17 Jul 2024 18:40:11 +0100

My new mechanical keyboard has arrived!

Ethernet Driver Features in 6.10

Tue, 16 Jul 2024 10:00:00 +0100

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.10.

Ethernet Driver Features in 6.9

Wed, 19 Jun 2024 09:00:00 +0100

A report of features and offloads implemented by ethernet drivers in Linux kernel 6.9.

What I'm doing now

Thu, 23 May 2024 10:28:15 +0100

Inspired to add a "now" page to my site.

Blog Housekeeping

Thu, 23 May 2024 09:00:00 +0100

Finally, finally getting around to some essential housekeeping of my literate blogging tools.

Floor796

Wed, 22 May 2024 20:22:04 +0100

My new favourite thing on the interwebs.

2023 AoC Day 19 – Aplenty

Fri, 22 Dec 2023 16:00:00 +0000

This is a solution to Advent of Code 2023 day 19, written in Raku.

2023 AoC Day 22 – Sand Slabs

Fri, 22 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 22, written in Raku.

2023 AoC Day 18 – Lavaduct Lagoon

Thu, 21 Dec 2023 22:00:00 +0000

This is a solution to Advent of Code 2023 day 18, written in Raku.

2023 AoC Day 21 – Step Counter

Thu, 21 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 21, written in Raku.

2023 AoC Day 16 – The Floor Will Be Lava

Wed, 20 Dec 2023 22:30:00 +0000

This is a solution to Advent of Code 2023 day 16, written in Raku.

2023 AoC Day 15 – Lens Library

Wed, 20 Dec 2023 19:00:00 +0000

This is a solution to Advent of Code 2023 day 15, written in Raku.

2023 AoC Day 14 – Parabolic Reflector Dish

Wed, 20 Dec 2023 16:00:00 +0000

This is a solution to Advent of Code 2023 day 14, written in Raku.

2023 AoC Day 20 – Pulse Propagation

Wed, 20 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 20, written in Raku.

2023 AoC Day 13 – Point of Incidence

Tue, 19 Dec 2023 22:00:00 +0000

This is a solution to Advent of Code 2023 day 13, written in Raku.

2023 AoC Day 12 – Hot Springs

Tue, 19 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 12, written in Raku.

2023 AoC Day 17 – Clumsy Crucible

Sun, 17 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 17, written in Raku.

2023 AoC Day 11 – Cosmic Expansion

Mon, 11 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 11, written in Raku.

2023 AoC Day 10 – Pipe Maze

Sun, 10 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 10, written in Raku.

2023 AoC Day 9 – Mirage Maintenance

Sat, 09 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 9, written in Raku.

2023 AoC Day 8 – Haunted Wasteland

Fri, 08 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 8, written in Raku.

2023 AoC Day 7 – Camel Cards

Thu, 07 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 7, written in Raku.

2023 AoC Day 6 – Wait For It

Wed, 06 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 6, written in Raku.

2023 AoC Day 5 – If You Give A Seed A Fertilizer

Tue, 05 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 5, written in Raku.

2023 AoC Day 4 – Scratchcards

Mon, 04 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 4, written in Raku.

2023 AoC Day 3 – Gear Ratios

Sun, 03 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 3, written in Raku.

2023 AoC Day 2 – Cube Conundrum

Sat, 02 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 2, written in Raku.

2023 AoC Day 1 – Trebuchet?!

Fri, 01 Dec 2023 00:00:00 +0000

This is a solution to Advent of Code 2023 day 1, written in Raku.

systemd ate my cat! 🙀

Thu, 09 Nov 2023 22:30:00 +0000

A Unicode text adventure in the land of Linux interface names where we cast systemd as the villain.

Teaching strace new tricks

Tue, 06 Jun 2023 22:15:53 +0100

Writing a code generator to produce strace source files from the openvswitch netlink schemas.

Kube Science Fiction

Thu, 18 May 2023 13:00:00 +0100

Write me some kubernetes science fiction.

As KubeGPT, my primary objective is to provide technical support and guidance for the use of Kubernetes, and I'm not particularly skilled in the realm of fiction writing! However, I can certainly give it a try.

Memorialising Terry Pratchett

Fri, 12 May 2023 13:18:36 +0100

Keeping the legacy of Sir Terry Pratchett alive forever. For as long as his name is still passed along the Clacks, Death can't have him.

Graphviz Examples

Fri, 12 May 2023 08:40:11 +0100

Some Graphviz examples that demonstrate custom layout and formatting techniques.

2022 AoC Day 7 – No Space Left On Device

Wed, 07 Dec 2022 00:00:00 +0000

This is a solution to Advent of Code 2022 day 7, written in Raku.

2022 AoC Day 6 – Tuning Trouble

Tue, 06 Dec 2022 00:00:00 +0000

This is a solution to Advent of Code 2022 day 6, written in Raku.

2022 AoC Day 5 – Supply Stacks

Mon, 05 Dec 2022 00:00:00 +0000

This is a solution to Advent of Code 2022 day 5, written in Raku.

2022 AoC Day 4 – Camp Cleanup

Sun, 04 Dec 2022 00:00:00 +0000

This is a solution to Advent of Code 2022 day 4, written in Raku.

2022 AoC Day 3 – Rucksack Reorganization

Sat, 03 Dec 2022 00:00:00 +0000

This is a solution to Advent of Code 2022 day 3, written in Raku.

2022 AoC Day 2 – Rock Paper Scissors

Fri, 02 Dec 2022 00:00:00 +0000

This is a solution to Advent of Code 2022 day 2, written in Raku and Rust.

2022 AoC Day 1 – Calorie Counting

Thu, 01 Dec 2022 00:00:00 +0000

This is a solution to Advent of Code 2022 day 1, written in Raku and Rust.

kgt in Org Babel

Sat, 27 Feb 2021 16:31:50 +0000

Making use of kgt in Emacs Org-mode with a new Babel driver.

Things We Owned

Sat, 20 Feb 2021 16:00:00 +0000

The computers and peripherals we owned in the 1980s.

If Sets Would DWIM

Tue, 26 Jan 2021 17:26:19 +0000

Whenever I work with Sets in Raku they often fail to DWIM. This is a short exploration to see if DWIMminess can be improved.

2020 AoC Day 25 – Combo Breaker

Tue, 12 Jan 2021 14:00:00 +0000

This is a solution to Advent of Code 2020 day 25, written in Raku.

2020 AoC Day 24 – Lobby Layout

Wed, 06 Jan 2021 18:00:00 +0000

This is a solution to Advent of Code 2020 day 24, written in Raku.

2020 AoC Day 23 – Crab Cups

Wed, 06 Jan 2021 10:00:00 +0000

This is a solution to Advent of Code 2020 day 23, written in Raku.

2020 AoC Day 22 – Crab Combat

Tue, 05 Jan 2021 22:00:00 +0000

This is a solution to Advent of Code 2020 day 22, written in Raku.

2020 AoC Day 21 – Allergen Assessment

Wed, 30 Dec 2020 10:00:00 +0000

This is a solution to Advent of Code 2020 day 21, written in Raku.

2020 AoC Day 20 – Jurassic Jigsaw

Mon, 28 Dec 2020 22:00:00 +0000

This is a solution to Advent of Code 2020 day 20, written in Raku.

2020 AoC Day 19 – Monster Messages

Mon, 28 Dec 2020 12:00:00 +0000

This is a solution to Advent of Code 2020 day 19, written in Raku.

2020 AoC Day 18 – Operation Order

Sun, 27 Dec 2020 18:00:00 +0000

This is a solution to Advent of Code 2020 day 18, written in Raku.

2020 AoC Day 17 – Conway Cubes

Sun, 27 Dec 2020 10:00:00 +0000

This is a solution to Advent of Code 2020 day 17, written in Raku.

2020 AoC Day 16 – Ticket Translation

Thu, 17 Dec 2020 15:10:00 +0000

This is a solution to Advent of Code 2020 day 16, written in Raku.

2020 AoC Day 15 – Rambunctious Recitation

Tue, 15 Dec 2020 16:45:00 +0000

This is a solution to Advent of Code 2020 day 15, written in Raku.

2020 AoC Day 14 – Docking Data

Tue, 15 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 14, written in Raku.

2020 AoC Day 13 – Shuttle Search

Mon, 14 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 13, written in Raku.

2020 AoC Day 12 – Rain Risk

Sun, 13 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 12, written in Raku.

2020 AoC Day 11 – Seating System

Sat, 12 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 11, written in Raku.

2020 AoC Day 10 – Adapter Array

Fri, 11 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 10, written in Raku.

2020 AoC Day 9 – Encoding Error

Thu, 10 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 9, written in Raku.

2020 AoC Day 8 – Handheld Halting

Wed, 09 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 8, written in Raku.

2020 AoC Day 7 – Handy Haversacks

Tue, 08 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 7, written in Raku.

2020 AoC Day 6 – Custom Customs

Mon, 07 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 6, written in Raku.

2020 AoC Day 5 – Binary Boarding

Sun, 06 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 5, written in Raku.

2020 AoC Day 4 – Passport Processing

Sat, 05 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 4, written in Raku and Python.

2020 AoC Day 3 – Toboggan Trajectory

Fri, 04 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 3, written in Raku and Python.

2020 AoC Day 2 – Password Philosophy

Thu, 03 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 2, written in Raku and Python.

2020 AoC Day 1 – Fix Your Expense Report

Wed, 02 Dec 2020 00:00:00 +0000

This is a solution to Advent of Code 2020 day 1, written in Raku and Python.

Combinations

Tue, 30 Jun 2020 10:30:05 +0100

This is a solution to the 67th Perl Weekly Challenge, written in Raku.

IPv4 Partition

Mon, 18 May 2020 22:23:20 +0100

This is a solution to task #2 from the 61st Perl Weekly Challenge, written in Raku.

Excel Columns

Sat, 16 May 2020 17:08:37 +0100

This is a solution to task #1 from the 60th Perl Weekly Challenge, written in Raku.

A Childhood at Sea

Mon, 30 Mar 2020 17:14:07 +0100

Most of my youth was spent at sea, sailing and dinghy racing from Cramond Boat Club.

Spelling Bee

Sun, 03 Nov 2019 17:39:31 +0000

A solver for the NYT daily Spelling Bee, written in Raku (nee Perl 6).

Stones and Jewels

Wed, 18 Sep 2019 23:26:22 +0100

This is a solution to task #1 from the 26th Perl Weekly Challenge, written in Perl 6.

The Vigenère Cipher

Thu, 04 Jul 2019 16:48:31 +0100

This is a solution to task #2 from the 15th Perl Weekly Challenge, written in Raku (nee Perl 6).

Van Eck by'eck

Mon, 24 Jun 2019 22:13:53 +0100

This is a solution to challenge #1 from the 14th Perl Weekly Challenge.

Postal Words

Mon, 24 Jun 2019 16:45:58 +0100

This is a solution to challenge #2 from the 14th Perl Weekly Challenge, written in Raku.

Roman Numerals in Raku

Wed, 29 May 2019 10:23:44 +0100

My first shot at the Perl Weekly Challenge with a Roman numeral encoder in Raku (nee Perl 6).

First Home Automation

Sun, 10 Mar 2019 11:30:00 +0000

Home automation on a budget, with a bit of DIY.

Blogging With Hugo and Org Babel

Wed, 12 Sep 2018 22:30:00 +0100

I think I have finally found a blogging platform that makes me happy. It needs to fit my programmer's workflow – git, markup and blogging about code. Hugo with org-babel nails it.

iPhone Camera Effects

Tue, 11 Sep 2018 20:30:31 +0100

What's going on here then? Chance pictures from an iPhone without any apparent skill at all.

Golfing Faster FASTA

Tue, 04 Sep 2018 20:45:00 +0100

After reading Timotimo's excellent Faster FASTA Please blog post, I wanted to test some of the available performance tradeoffs.

A Twist To The Rational Story

Sun, 02 Sep 2018 21:00:00 +0100

As a followup to brrt's Curious Benchmark post, I wanted to explore some of the questions that were left unanswered.

Embedding Perl6 in Eclipse

Sat, 26 Jul 2014 19:02:02 +0100

[Coke] asked me a simple question on irc:

donaldh: have you any idea how to bundle perl6 in a jar we could invoke from eclipse?

This tickled my urge to explore embedding Rakudo / JVM, to refresh my knowledge of Eclipse and also to have some fun hacking with Perl 6.