NextBSD is back with a new FreeBSD-Apple mix

NextBSD is back after years of inactivity, reviving a long-running attempt to combine Apple’s open-source Darwin components with the FreeBSD kernel. The reboot is being led by Joe Maloney, known on GitHub as pkgdemon, who previously worked on the Gershwin desktop in GhostBSD.

This is not a continuation of the old codebase. The original NextBSD was started by FreeBSD co-founder Jordan Hubbard in 2015, with the goal of porting parts of Darwin — the Unix foundation beneath macOS, iOS, and Apple’s other operating systems — onto FreeBSD. The new project starts fresh, reflecting how much both FreeBSD and Darwin have changed over the past decade, though it still reuses some earlier code.

The core idea remains the same: keep FreeBSD’s kernel, but replace parts of its traditional, server-focused userland with publicly available Apple components such as launchd, IOKit, Apple System Log, syslogd, and pieces built around XNU and Mach IPC. That is a difficult task, as earlier Darwin-on-PC efforts including OpenDarwin (2002–2006), PureDarwin (releases in 2015 and 2019, still maintained as recently as 2024), GNU Darwin, and DarwinBSD all struggled to sustain momentum.

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For now, NextBSD-redux is still early. The README and porting notes outline what works, and there is no graphical desktop yet, although Maloney is also bringing over Gershwin. The project also pulls in some code shared across related efforts, including ravynOS libraries such as libxpc, which originated in the first NextBSD project.

That cross-pollination is a recurring theme here. helloSystem, covered by The Register in 2021 and again in 2023 with version 0.8, was built by Simon “ProbonoPD” Peter on top of FuryBSD, which shut down in 2020. Peter later moved to help with Gershwin. ravynOS, which at one stage was effectively based on helloSystem, pushed further by aiming for limited macOS binary compatibility through Darling. Its current architecture starts with Darwin 19.6, corresponding to macOS 10.15 Catalina.

Maloney first publicly discussed the new NextBSD in May, including in a Reddit thread titled “NextBSD – the BSD of the 21st century.” One part of the reboot is likely to divide developers: he says he is using Anthropic’s Claude Code as part of the project.

“From my perspective, AI is a force multiplier here. It is my team of developers, but I am steering the entire thing. I can understand that won’t be for everyone. If others happen to like it, awesome. If others happen to contribute later, awesome. I selfishly just enjoy doing it, and want it to exist for myself. I can think of no better name for the project than NextBSD.”

Maloney told The Register he shares some of the skepticism around machine-generated code and does not fully trust it without human review. He said he first used it heavily for planning and research, then for more interactive code review and test development as the project evolved through multiple internal iterations.

According to Maloney, the oldest commits in the public nextbsd-redux repository are only two months old, but the work started earlier in private. He described three iterations: a first attempt focused on a sockets-only version of launchd; a second that added a Mach kernel module and reused glue code such as libxpc; and a third that split the system into separate repositories for the kernel, modules, and Darwin-derived tooling, all with GitHub-based cross-building and automated test gates.

For now, NextBSD remains an experiment in stitching together existing FOSS parts rather than building a new OS from scratch. The immediate question is whether that mix of FreeBSD, Darwin, Mach, and shared code from projects like ravynOS can progress from an intriguing prototype to a laptop-ready operating system.