Gregory Kurtzer uses Codex to build Ginux, a Linux-compatible kernel, in 11 days

Gregory Kurtzer, who created CentOS and started Rocky Linux, said on X on October 27, 2026 that he had built Ginux, a new Linux-compatible kernel, in 11 days. He said it boots Rocky Linux 10 through systemd. Ginux is not a fork of Linux. Kurtzer says it has its own memory management, boot process, scheduler, process model, filesystems, networking, device support and Linux compatibility layer. The code is mostly Rust, and the repository is on GitHub under the Apache 2.0 license.

Ginux implements the Linux ABI, the binary interface that compiled programs use to talk to the kernel, so unmodified Linux programs can run on it. The project's README describes Linux as a personality the kernel exposes to software, not the code running underneath. Work is organized into domains, each with its own processes, address space, filesystem and lifecycle. The README says domains are stronger boundaries than OCI containers or Linux namespaces. Ginux still uses OCI container images as a delivery format. It pulls, verifies and assembles them into a domain's root filesystem, which is how a Rocky Linux 10 userspace reaches systemd's multi-user.target. Selected Alpine Linux programs, using musl and BusyBox, also run.

The development method is what Kurtzer emphasizes, and he calls it Human-Directed Agentic Engineering. The human sets the architecture, constraints, milestones, acceptance criteria and stopping points. An AI agent then implements, tests, diagnoses failures and revises. For Ginux, that meant one persistent OpenAI Codex task using GPT-5.6 Sol. Kurtzer's post says the task produced approximately 139,000 retained lines of implementation and test code. TechSpot and It's FOSS both report more than 1,000 commits. TechSpot adds that real distributions such as Rocky Linux exposed bugs that the project's synthetic tests missed. The 139,000 figure combines implementation and test code, and the announcement doesn't break out how much is kernel code.

The README gives the most specific accounting of what works. It classifies all 375 syscall numbers in Linux 6.12's x86-64 interface: 53 complete, 257 partial, 17 unsupported with a Linux-compatible ENOSYS error, and 48 policy-denied. The README says that classification means every number has an explicit disposition, not that Linux conformance is complete. TechSpot reported different figures, 82 fully implemented and 245 partly working, which don't match the README's ledger. Ginux's validated development target is a QEMU virtual machine. The README lists no physical hardware profile, no GPU or NVMe support, and no independent security audit. It describes the project as a research prototype, not suitable for production workloads.

The README also says the project is changing direction. The standalone kernel is now frozen except for resolving work already open, and no new issues or pull requests are being accepted for it. Active development is moving to Ginux Userspace, a lightweight, configurable userspace kernel that runs as an ordinary process on a Linux host and uses the host for hardware execution. The README says Ginux's first experiment succeeded in its goal, and that building a kernel which runs Linux userspace is not the same as building a credible alternative to Linux. The standalone kernel will remain public for study and forking, and the README says the successor's history will later be merged into the main Ginux line.