diff --git a/NOTES.md b/NOTES.md
index 883ac21..ec97cab 100644
--- a/NOTES.md
+++ b/NOTES.md
@@ -1,30 +1,65 @@
 # ToDo's
 
-- find a good abstraction for systems that allows setting nixpkgs.localSystem per systems
-  - e.g. build utility function with a module based interface to set things like march and hostname
+- https://nixos.wiki/wiki/Binary_Cache
+- build a good abstraction for systems 
+  - allows setting nixpkgs.localSystem per systems
   - should yield a `nixosConfiguration.${hostname} = nixpkgs.lib.nixosSystem {...}`
-- set localSystem per system like this:
-  ```nix
-  # to allow building
-  nix.extraOptions = ''
-    system-features = system-features = gccarch-znver2
-  '';
-  # to actually build (after rebuilding with the feature before)
-  localSystem = {
-    inherit system;
-    gcc = {
-      arch = "znver2";
-      tune = "znver2";
+  - example module abstraction
+    ```nix
+    # TODO think about partitions/hardware/system specific conf
+    # TODO think about hardware.nix like things
+    { config,
+      inputs,
+      lib,
+      ...
+    }: {
+      home_conf = {
+        # ...
+      };
+      os_conf = {
+        # ...
+      };
+    }
+  - example mkSystem abstraction
+    ```nix
+    let opts = {
+      hostname = "test";
+      opt = "znver2";
+      users = {
+        { name = "tristand", groups=[..] },
+        { name = "tester", groups=[..] },
+      };
+      modules = [
+        ./my_module.nix
+      ];
     };
-  };
-  pkgs-args = {
-    inherit localSystem;
-    inherit overlays;
-    config = {
-      # ....
+    in {
+      mylib.mkSystem opts?            #
+      # take a path? just let the user call import ?
+    }
+    ```
+  - example localSystem conf
+    ```nix
+    # to allow building
+    nix.extraOptions = ''
+      system-features = system-features = gccarch-znver2
+    '';
+    # to actually build (after rebuilding with the feature before)
+    localSystem = {
+      inherit system;
+      gcc = {
+        arch = "znver2";
+        tune = "znver2";
+      };
     };
-  };
-  pkgs = import nixpkgs pkgs-args;
-  nixpkgs.pkgs = pkgs;
-  ```
+    pkgs-args = {
+      inherit localSystem;
+      inherit overlays;
+      config = {
+        # ....
+      };
+    };
+    pkgs = import nixpkgs pkgs-args;
+    nixpkgs.pkgs = pkgs;
+    ```
 - switch from security.sudo.* to security.sudo-rs.*