···

       
41
       
41
       
 
       
      - SBCs are small mammals ([Eulipotyphla](https://en.wikipedia.org/wiki/Eulipotyphla)), e.g. the [Home Assistant](https://www.home-assistant.io/) server and [Zigbee](https://en.wikipedia.org/wiki/Zigbee) bridge [`shrew`](./hosts/shrew).

     

       
42
       
42
       
 
       
      - Desktops are carnivores ([Carnivora](https://en.wikipedia.org/wiki/Carnivora)), e.g. the tower PC [`vulpine`](./hosts/vulpine).

     

       
43
       
43
       
 
       
    - Mobile (battery powered) hosts are reptiles, e.g. the laptop [`gecko`](./hosts/gecko).

     

       
44
       
44
       
-
       
    - Virtual hosts are birds, e.g. the virtual private server [`owl`](./hosts/owl).

     

       
45
       
45
       
-
       
    - Work-associated hosts are aquatic.

     

       
44
       
44
       
+
       
    - Virtual hosts are birds, e.g. the virtual private server (VPS) [`owl`](./hosts/owl).

     

       
45
       
45
       
+
       
    - Work-associated hosts are aquatic, e.g. the VPSs for [Eon](https://github.com/RyanGibb/eon) experiments [`duck`](./hosts/duck), and running the [EEG](https://www.cst.cam.ac.uk/research/eeg) infrastructure including using the federated [Shibboleth](https://www.shibboleth.net/) identity server to provision [Matrix](https://matrix.org/) accounts [`swan`](./hosts/swan).

     

       
46
       
46
       
 
       
    - [`barnacle`](./hosts/barnacle/default.nix) builds an ISO image that can be written to media like a USB flash drive to create a read-only live USB that can be booted to provide the custom environment on all my other hosts and used to, for example, install an operating system, with the [`install.sh`](./hosts/barnacle/install.sh) script.

     

       
47
       
47
       
 
       
  - Each host directory typically contains,

     

       
48
       
48
       
 
       
    - `default.nix` - Main configuration entry point that imports other modules.

     

       
49
       
49
       
 
       
    - `hardware-configuration.nix` - Hardware-specific configuration generated by `nixos-generate-config`.

     

       
50
       
50
       
-
       
    - `minimal.nix` - A minimal configuration that can be useful when updating with insuffient disk space.

     

       
50
       
50
       
+
       
    - `minimal.nix` - A minimal configuration that can be useful when updating with insufficient disk space.

     

       
51
       
51
       
 
       
      The minimal configuration can be build, the `default.nix` system garbage collected, and then the updated configuration built.

     

       
52
       
52
       
 
       
      Note this precludes trivial rollback.

     

       
53
       
53
       
-
       
    - Other modules seperating functionality, such as `services.nix`.

     

       
53
       
53
       
+
       
    - Other modules separating functionality, such as `services.nix`.

     

       
54
       
54
       
 
       
- [`modules/`](./modules/) - NixOS modules of common functionality extracted into modular components which can be enabled by host configurations.

     

       
55
       
55
       
 
       
- [`pkgs/`](./pkgs/) - Custom package definitions for packages not available in nixpkgs or requiring modifications.

     

       
56
       
56
       
 
       
- [`home/`](./home/) - Home-manager NixOS modules configurations.