Why custom software breaks the traditional operating system

Operating systems were built to isolate code written by strangers, but that architecture fails when you start building your own apps.

Developer Thomas Ptacek announced his departure from Fly.io to build a new phone and computing platform. Writing on his blog, Ptacek argues that AI lets anyone generate hyper-specific, single-user software using plain English. Because modern operating systems were designed around deterministic, prepackaged software from third-party vendors, he contends the underlying OS architecture must change.

Why it matters: Today's operating systems isolate applications to keep unknown programs from interfering with each other. That model makes little sense when apps are generated by the user, constantly shape-shifting, and built to solve micro-problems for an audience of one. Our devices still rely on 1970s concepts built for fixed software, leaving a gap for platforms designed around personal, disposable code.

Here's the gist: instead of downloading rigid apps built by strangers, we will increasingly generate tiny tools for single tasks, like custom route pickers or local weather tools.

We spent fifty years running other people's programs, but the next OS might finally run yours.