anchor.diff:    fillDiskWithRPMs =
       { size ? 4096, rpms, name, fullName, preInstall ? "", postInstall ? ""
       , runScripts ? true, createRootFS ? defaultCreateRootFS
  +    , unifiedSystemDir ? false
       }:
   
       runInLinuxVM (stdenv.mkDerivation {
  
positive.code: 
          rm /mnt/.debug
  
          ${utillinux}/bin/umount /mnt/nix/store
          ${utillinux}/bin/umount /mnt/tmp
          ${utillinux}/bin/umount /mnt
        '';
  
  
negative.code:         name = "redhat-9-i386";
          fullName = "Red Hat Linux 9 (i386)";
          size = 1024;
          rpms = import ./rpm/redhat-9-i386.nix { inherit fetchurl; };
        };
  
        suse90i386 = fillDiskWithRPMs {
          name = "suse-9.0-i386";
          fullName = "SUSE Linux 9.0 (i386)";
          size = 1024;
          rpms = import ./rpm/suse-9-i386.nix { inherit fetchurl; };
          # Urgh.  The /etc/group entries are installed by aaa_base (or
          # something) but due to dependency ordering, that package isn't
          # installed yet by the time some other packages refer to these
  