NuBus expansion bus for classic Apple Macintosh systems
NuBus is the 32-bit expansion slot standard Apple used in Macintosh II, Quadra, and early Power Macintosh systems from the late 1980s until Apple switched to PCI in the mid-1990s. This code scans NuBus slots, reads card identification ROMs, and exposes installed cards (graphics, networking, SCSI, video capture, etc.) to the rest of the kernel on m68k and PowerPC Macs.
recommendation
Worth keeping but documenting its niche: the hardware has not shipped in new machines since around 1995, but Linux still supports classic Macintosh systems on m68k, and the code is actively maintained by Finn Thain, who landed real bug fixes as recently as 2023 and late 2025 against machines with multiple NuBus cards installed. It is firmly retro-computing territory rather than a removal candidate.
repository signals
sources
- patch.msgid.link
NuBus code still received a maintainer-authored bug fix in December 2025, indicating ongoing upstream maintenance rather than abandonment.
- lore.kernel.org
A 2023 patch changed default procfs behavior based on measured runtime and memory costs on a test machine with several NuBus cards installed, showing real-hardware use and maintenance.
- lore.kernel.org
A 2023 fix addressed malformed NuBus card ROMs causing procfs warnings, further indicating bug-fix traffic for existing legacy hardware.
- en.wikipedia.org
NuBus was used mainly in Apple Macintosh systems and disappeared from mainstream systems after Apple switched to PCI in the mid-1990s, so it is not new-deployment hardware in 2025.
- cateee.net
Linux still carries Macintosh platform support on m68k, consistent with continued niche support for legacy Macintosh hardware that can host NuBus.
codex reasoning notes (technical)
Local source inspection showed this directory is real NuBus bus/scan code with initcalls, not a helper library. Upstream activity was checked via local `git log` on `drivers/nubus`; the cited 2023 and 2025 patch URLs came from commit `Link:` trailers returned by that command. No removal series was found in the inspected recent history, while multiple non-mechanical fixes exist, so `remove`/`deprecate` would overstate the case. Deployment evidence came from web search results for NuBus and Linux Macintosh support: Wikipedia indicates mainstream NuBus systems ended when Apple moved to PCI in the mid-1990s, and LKDDb shows Linux still supports Macintosh/m68k. Conclusion: hardware is long obsolete and only niche retro deployments remain, but upstream still fixes it, so `keep-annotate` is the best fit.