Library articles are substantial: explanations, analysis, technical specifications, or historical context, useful for reference. I often keep them updated.
See also Notes and Research, or browse by topic.
Digital freedom and law#
The battles over who controls software, data, and communications have been running for thirty years and are not over. These articles cover the legal and policy terrain — patents, privacy law, data sovereignty — from being in the middle of it.
Software you can trust#
A recurring theme in my work is that software fragility is underestimated and under-addressed. These projects and articles approach that problem from different angles — data integrity, reproducibility, reversibility, and version control.
- LumoSQL — Modifying SQLite to give device owners genuine control over their own data, without breaking compatibility.
- Reversible Execution — Rewinding and replaying software to find bugs and security problems. Still the biggest advance in debugging since source-level debuggers.
- Logical and Thermodynamic Reversibility — How reversibility connects to the energy crisis in AI infrastructure.
- Not Before Time — Time-locking information using existing tools and tried mathematics.
- Not Forking — Automating change management across source trees in ways version control systems cannot.
- Fossil — The only realistic alternative to Git, with stronger cryptographic and reproducibility guarantees.
- How to Replace Windows NT with Linux — Written at Linuxcare in 1999. Historical, but part of the Samba story.
AI safety and agentic systems#
Current AI safety efforts focus on making individual models better-behaved. My work on the Perseverance Composition Engine takes a different approach: structure the system so that misbehaviour is caught before it causes harm, the way human institutions have worked for centuries. These articles develop that argument and its technical context.
Practice and teaching#
- Security Standards and Certifications — How the major standards work in practice, and why their bad reputation is mostly undeserved.
- Teaching Exercises — Exercises in cybersecurity and computer science I have used over many years of mentoring.
- Code of Conduct — A concise code of conduct for open source projects, compressed from the Mozilla Participation Guidelines.
- BibLaTeX, eras and scripts — Managing references across non-Latin scripts, ancient sources, and non-English languages in LaTeX.
This is a technical note about a problem that is going to bite agentic AI users soon.
AI is slow, and Agentic AI is even slower. I develop an MCP server that generates PDF documents, and I work with the Agentic Perseverance Composition Engine daily, and AI seems so, so slow. There’s so much waiting, and every mistake means yet more sitting around. Tasks we know actually take maybe 5 microseconds on an operating system (eg, does a file called Things-to-Do exist?) can take one million time longer – between 2 and 5 seconds. This is because the big brain in the cloud is being consulted multiple times, often with timeouts. It’s a young, unstable and unreliable stack, rather like the early days of MS DOS or the Apple ][. When AI gets hold of the data from your computer via an MCP server it can do some very interesting things, but it is not put together well.
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From time to time I am engaged to help organisations in the UK and in the EU make decisions about where their data is stored, how it is accessed, and how to keep things as stable as possible over the next few years. This was a dizzying mess until 2025, and in 2026 there are some big decisions coming. Organisations need as much certainty as they can get for making decisions which are expensive to change in the future.
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This file is a Code of Conduct first written in 2020 for the LumoSQL project. Here is Version 1.6 – Updated 9th February, 2026. Heavily adapted and compressed from the large and repetitive version 3.1 of the Mozilla Participation Guidelines and published by LumoSQL under the Creative Commons Attribution-ShareAlike 4.0 International license.
Contents LumoSQL Code of Conduct This file exists because the LumoSQL Project needed it, less than one year after starting in 2019. We take it seriously, and hope that most English-reading adults can understand what is said. We hope this is not needed very often.
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The detail of the GDPR and its implied computer science contain a solution for sharing secrets according to law. This continues to be true in 2026, as the Digital Omnibus Regulation takes shape.
Executive Summary
The GDPR sets up a conflict in trust between companies in particular circumstances, which can only be resolved by using the automation of a cryptographic audit trail with particular properties as described below.
Problem Statement
Under the EU’s GDPR law virtually every company is a Controller, and virtually all Controllers use at least one Processor. When a Processor is engaged, the GDPR requires that a contract is signed with the very specific contents spelled out in clause 3 of Article 28. The GDPR requires that Controllers and Processors cooperate together in order to deliver data protection, and this cooperation needs to be very carefully managed to maintain the security and other guarantees that the GDPR also requires. That’s what this mandatory contract is intended to achieve.
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This is the second time the Court of Justice has decided the same question. In brief, after 4 years, in 2020 the Court was completely satisfied that the United States violates the privacy of EU citizens when the personal data of EU citizens is visible to the US government, and that the US has no intention of changing its behaviour. Therefore, US companies are not permitted to hold the personal data of EU citizens and residents.
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The Fossil source code management system is the most fully-featured alternative to Git, and has had twenty years of development and testing since 2006. After helping Fossil make some changes I now use Fossil for several projects. I also use Git extensively on various software forges (but not GitHub unless I must). Mercurial is actively maintained but has lost most of its mindshare since Mozilla, Bitbucket and others migrated away, and is rarely chosen for new projects today.
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LumoSQL protects data on mobile phones using a new data storage technology which is highly compatible with most existing devices. With LumoSQL, the device owner has ultimate right to decide who can read or change their data… and this decision continues to be enforced even after it has been copied off the phone to (for example) a bank or insurance company for processing with their in-house database software. In contrast, the situation at present is that device owners are rarely in control of the privacy of their own data, despite many laws relating to privacy.
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I participated in many battles directly against Microsoft in the Ballmer era, 1998-2014. Every Samba feature release seem to further anger Microsoft. Copyright and then especially patents were weaponised, as well as well-funded hit teams aimed at spreading confusion and intimidating their own (Microsoft’s!) customers. In the Nadalla era from 2014-present, Microsoft and other tech giants are using even more brutal ways (paracopyright, technical protection measures and the Unitary Patent System), to coerce citizens and governments.
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This timeline covers the period when Microsoft decided free software and Samba in particular was an exisential threat. Microsoft often buried competitors in expensive legislation, but turned out to be much more difficult to bury open source like Samba. This was the Ballmer era, named after the then-CEO, and the history of Samba’s triumphs feels highly relevant to 2026 where other giant companies seek to prevent the rise of open source competitors.
In 2014, Microsoft got a new CEO and dramatically changed course from explicit hostility to embracing open source. The battleground is now about paracopyright and preventing non-US cloud but it has its roots in the great open source IP battles of the 21st century.
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In 2026, the Samba Project is nearly 30 years old and has conservatively a billion users. Samba started when I got upset at Microsoft for trying to monopolise all computer networking. I discovered some unmaintained but interesting open source software for sharing files and printers with workstation computers. And the rest is the official Samba history.
Samba is implemented by talented software engineers with a very large number of total contributors. I was (and remain) most interested in interoperability architecture and design, why these things are needed and make sense to users. Plus some protocol analysis, for example, technical readers may know the NTLMv2 encryption scheme was tricky, but turned out to be the same as used in the NTFS filesystem - NTLM is deprecated in favour of Kerberos now but those were the days. I wrote How to Replace Windows NT with Linux, explaining protocol-first strategies for removing Microsoft software.
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