anchor.diff:        {config, pkgs, ...}:
         {
           services = {
  +	  portmap = {
  +	    enable = true;
  +	  };
  +
             nfsKernel = {
               enable = true;
  -          };
  +          };	  
     
             httpd = {
               enable = true;
  
positive.code:         services = {
  	  xserver = {
  	    enable = true;
              driSupport = true;
  	  };
  	};
  	  
          environment = {
  	  extraPackages = [
  	    pkgs.firefox
  	    pkgs.icewm
  	    pkgs.scrot
  	  ];
  	};
  
negative.code:     
            postgresql = {
              enable = true;
      	    enableTCPIP = true;
  	    
              authentication = ''
                # Generated file; do not edit!
                local all all                trust
                host  all all 127.0.0.1/32   trust
  	      host  all all ::1/128        trust
  	      host  all all 192.168.1.0/24 trust
              '';
            };
          };  
  