Theo de Raadt was a founding member of the NetBSD project, one of the original free BSD operating systems that emerged from the UC Berkeley codebase in the early 1990s. He was also, by most accounts, extraordinarily difficult to work with. Peter Wayner wrote that de Raadt 'began to rub some people the wrong way,' and Linus Torvalds once described him simply as 'difficult.' But difficult people sometimes produce extraordinary things.

In December 1994, the NetBSD core team asked de Raadt to resign, citing personality conflicts and disagreements over development practices. When he refused, they revoked his CVS access—effectively expelling him from the project he'd helped found. The specifics remain somewhat murky, but the pattern is clear: a brilliant, abrasive developer whose interpersonal style became incompatible with the project's culture.

Rather than slinking away, de Raadt forked NetBSD 1.0 in October 1995 and created OpenBSD with a singular obsession: security. While other operating systems treated security as one concern among many, de Raadt made it the organizing principle. OpenBSD pioneered proactive code auditing—systematically reviewing the entire codebase for vulnerabilities rather than waiting for them to be discovered in the wild.

The results speak for themselves. OpenBSD has had only two remote holes in the default install in its entire history. The project produced OpenSSH, which became the de facto standard for secure remote access across virtually every operating system on Earth. It also produced OpenBGPD, OpenNTPD, LibreSSL, and other security-critical infrastructure that's used far beyond OpenBSD itself.

By 2024, the project had diverged so completely from its origins that every single file from the original NetBSD fork had been either modified or removed. The expulsion of one difficult developer resulted in some of the most important security infrastructure in computing history.

OpenBSD's impact on computing security is almost impossible to overstate. OpenSSH is installed on billions of devices and is the backbone of secure remote administration worldwide. The project's code audit practices influenced security thinking across the entire software industry, and its motto ('Only two remote holes in the default install') set a standard that few other operating systems can match.

Beyond direct contributions, OpenBSD demonstrated that a fork driven by a strong (even abrasive) technical vision can produce results that benefit the entire computing ecosystem. The NetBSD team may have had valid interpersonal complaints about de Raadt, but the world got OpenSSH out of the deal.