The Free and Open Source Software Yearly conference (FOSSY) moved to the University of British Columbia in Vancouver, Canada, after three years in Portland, Oregon. In the "Toolchains and Other Development Tools" track, Timothy Sample presented on bootstrappable builds, a concept less known than reproducible builds. A bootstrappable build starts with a tiny program that builds progressively larger programs until a modern Linux user space is constructed from a small seed, resulting in code with a completely understood origin.

Sample noted the audience's surprising familiarity with the topic. He began pursuing bootstrappable builds nearly ten years ago using GNU Guix, a functional package manager inspired by Nix. Both systems represent software in a "derivation graph" mapping hundreds of build dependencies. Sample illustrated the complexity using a Python program requiring a C compiler, which requires another compiler, ad infinitum. Traditionally, systems like Debian stop at a pre-uploaded C compiler binary, while Guix originally stopped at a 250MB statically linked blob of GNU user-space programs.

The core goal is building a system without relying on pre-built artifacts. Sample compared standard compilation to making yogurt requiring a starter culture, or using "Dennis Ritchie's starter carried over from Bell Labs." This challenge applies to most self-hosting languages. Bootstrappable builds aim to eliminate these opaque binary seeds, ensuring a verifiable software supply chain from zero to a modern system.