Emma Thorpe
0d13581896
Claude Code runs on Node, whose V8 build requires SSE4.2 and POPCNT (x86-64-v2). On an older x86_64 CPU it does not run, so it must not be installed there in the first place. Nix cannot detect the CPU (pure evaluation, hosts often built elsewhere), so add features.cpu.microarchLevel: the psABI level a host declares about itself, defaulting to 2. features.claudeCode.enable derives from it, and home/claude.nix reads that through home-manager's osConfig and installs nothing -- CLI, CLAUDE.md, output style or memory symlink -- when it is off. Hosts without the option (Darwin, the standalone homeConfigurations) keep the tool enabled. An assertion fails evaluation if a host force-enables the flag below the required level, so the mistake surfaces in nix flake check rather than as an illegal-instruction crash on the machine.
Mac Pro 3,1 (Early 2008) — install notes
Flake host: lyrathorpe-macpro31. Desktop (portable = false, imports
../../modules/desktop.nix). Files: configuration.nix,
hardware-configuration.nix.
Hardware configuration
hardware-configuration.nix here is the real config generated by
nixos-generate-config on the machine. Root is an LVM logical volume
(/dev/mapper/MacPro-Root, ext4); the ESP (vfat) and swap are referenced by
UUID. The initrd carries dm-snapshot for the LVM root. Regenerate and commit
if the disk layout changes.
Bootloader
The Mac Pro 3,1 has 64-bit EFI, so it uses systemd-boot (no GRUB/CSM
shim). canTouchEfiVariables = false because Apple's firmware does not reliably
accept efibootmgr NVRAM writes.
Apple-EFI quirk: if the firmware boot picker does not show NixOS after install, either
- uncomment
boot.loader.efi.efiInstallAsRemovable = true;inconfiguration.nix(installs the fallback\EFI\BOOT\BOOTX64.EFI), and/or - "bless" the ESP from macOS.
Partition the disk GPT with an ESP (vfat).
Graphics
The stock card varies between units — ATI Radeon HD 2600 XT or NVIDIA GeForce 8800 GT. No proprietary driver is hardcoded; Sway relies on in-tree KMS:
- ATI Radeon HD 2600 XT →
radeon(oramdgpu) KMS - NVIDIA GeForce 8800 GT →
nouveauKMS
These come up automatically. If a card needs forcing, set
services.xserver.videoDrivers and/or add the module to
boot.initrd.kernelModules for early KMS (see the comment in
configuration.nix).
Networking
Wired Ethernet via NetworkManager (from desktop.nix) — the Mac Pro has two
gigabit ports.
Login
Graphical login via a Wayland greeter — greetd running ReGreet inside the
cage kiosk compositor — configured centrally in ../../modules/sway.nix for
every Sway host (gated on features.swayDesktop.enable). The greeter is forced
to the Dvorak layout to match the console and Sway session. Set the user
password (passwd lyrathorpe) after install, or the greeter cannot
authenticate. Requires working KMS (radeon/nouveau — see Graphics).
Apply
sudo nixos-rebuild switch --flake .#lyrathorpe-macpro31