diff --git a/src/db/db/dbDeepShapeStore.cc b/src/db/db/dbDeepShapeStore.cc
index e7fc66bcb..9d3f117d1 100644
--- a/src/db/db/dbDeepShapeStore.cc
+++ b/src/db/db/dbDeepShapeStore.cc
@@ -235,6 +235,11 @@ struct DeepShapeStore::LayoutHolder
     return m_empty_layer;
   }
 
+  unsigned int new_empty_layer ()
+  {
+    return layout.insert_layer ();
+  }
+
   void add_layer_ref (unsigned int layer)
   {
     layer_refs [layer] += 1;
@@ -577,6 +582,17 @@ DeepLayer DeepShapeStore::empty_layer () const
   return empty_layer (0);
 }
 
+DeepLayer DeepShapeStore::new_empty_layer (unsigned int layout_index) const
+{
+  return DeepLayer (const_cast<DeepShapeStore *> (this), layout_index, m_layouts[layout_index]->new_empty_layer ());
+}
+
+DeepLayer DeepShapeStore::new_empty_layer () const
+{
+  require_singular ();
+  return new_empty_layer (0);
+}
+
 DeepLayer DeepShapeStore::create_custom_layer (const db::RecursiveShapeIterator &si, HierarchyBuilderShapeReceiver *pipe, const db::ICplxTrans &trans)
 {
   unsigned int layout_index = layout_for_iter (si, trans);
diff --git a/src/db/db/dbDeepShapeStore.h b/src/db/db/dbDeepShapeStore.h
index 2c92f39f7..ff914a621 100644
--- a/src/db/db/dbDeepShapeStore.h
+++ b/src/db/db/dbDeepShapeStore.h
@@ -356,6 +356,19 @@ public:
    */
   DeepLayer empty_layer () const;
 
+  /**
+   *  @brief Gets a new empty working layer
+   *
+   *  This method will deliver an empty layer for the given layout index. This layer is a fresh one and can be
+   *  modified.
+   */
+  DeepLayer new_empty_layer (unsigned int layout_index) const;
+
+  /**
+   *  @brief Gets a new empty working layer for the singular layout
+   */
+  DeepLayer new_empty_layer () const;
+
   /**
    *  @brief Inserts the deep layer's shapes into some target layout
    */
diff --git a/src/db/db/dbLayoutToNetlist.cc b/src/db/db/dbLayoutToNetlist.cc
index eb72fad6e..ad86e969d 100644
--- a/src/db/db/dbLayoutToNetlist.cc
+++ b/src/db/db/dbLayoutToNetlist.cc
@@ -92,6 +92,14 @@ LayoutToNetlist::~LayoutToNetlist ()
   m_net_clusters.clear ();
 }
 
+void LayoutToNetlist::keep_dss ()
+{
+  if (mp_dss.get () && ! mp_internal_dss.get ()) {
+    mp_dss->keep ();
+    mp_internal_dss.reset (mp_dss.get ());
+  }
+}
+
 void LayoutToNetlist::init ()
 {
   dss ().set_text_enlargement (1);
diff --git a/src/db/db/dbLayoutToNetlist.h b/src/db/db/dbLayoutToNetlist.h
index 5e61137c7..cb5485a8b 100644
--- a/src/db/db/dbLayoutToNetlist.h
+++ b/src/db/db/dbLayoutToNetlist.h
@@ -114,6 +114,11 @@ public:
    */
   ~LayoutToNetlist ();
 
+  /**
+   *  @brief Makes the extractor take over ownership over the DSS when it was created with an external DSS
+   */
+  void keep_dss ();
+
   /**
    *  @brief Gets the database description
    */
diff --git a/src/db/db/dbNetlistDeviceExtractor.cc b/src/db/db/dbNetlistDeviceExtractor.cc
index b2b4218a0..cfaa1e352 100644
--- a/src/db/db/dbNetlistDeviceExtractor.cc
+++ b/src/db/db/dbNetlistDeviceExtractor.cc
@@ -154,7 +154,8 @@ void NetlistDeviceExtractor::extract (db::DeepShapeStore &dss, unsigned int layo
         l = layer_map.find (ln);
       }
 
-      throw tl::Exception (tl::to_string (tr ("Missing input layer for device extraction: ")) + layer_names);
+      //  TODO: maybe use empty layers for optional ones?
+      throw tl::Exception (tl::sprintf (tl::to_string (tr ("Missing input layer for device extraction (device %s): %s")), name (), layer_names));
 
     }
 
@@ -167,8 +168,9 @@ void NetlistDeviceExtractor::extract (db::DeepShapeStore &dss, unsigned int layo
         //  use deep layer alias for a given flat one (if found)
         layers.push_back (alias.second.layer ());
       } else if (l->second->empty ()) {
-        //  provide a substitute empty layer
-        layers.push_back (dss.empty_layer (layout_index).layer ());
+        //  provide a substitute empty layer (CAUTION: we can't use the
+        //  singleton "empty_layer" because this may be used as OUTPUT).
+        layers.push_back (dss.new_empty_layer (layout_index).layer ());
       } else {
         throw tl::Exception (tl::sprintf (tl::to_string (tr ("Invalid region passed to input layer '%s' for device extraction (device %s): must be of deep region kind")), ld->name, name ()));
       }
diff --git a/src/db/db/gsiDeclDbLayoutToNetlist.cc b/src/db/db/gsiDeclDbLayoutToNetlist.cc
index c7db7b5fe..02b8d31a1 100644
--- a/src/db/db/gsiDeclDbLayoutToNetlist.cc
+++ b/src/db/db/gsiDeclDbLayoutToNetlist.cc
@@ -147,7 +147,9 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "add layers (regions) inside the 'dss' object.\n"
     "\n"
     "The make_... methods will not create new layers as there is no particular place "
-    "defined where to create the layers."
+    "defined where to create the layers.\n"
+    "\n"
+    "The extractor will not take ownership of the dss object unless you call \\keep_dss."
   ) +
   gsi::constructor ("new", &make_l2n_from_existing_dss_with_layout, gsi::arg ("dss"), gsi::arg ("layout_index"),
     "@brief Creates a new extractor object reusing an existing \\DeepShapeStore object\n"
@@ -167,6 +169,12 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "The database unit is mandatory because the physical parameter extraction "
     "for devices requires this unit for translation of layout to physical dimensions.\n"
   ) +
+  gsi::method ("dss", (db::DeepShapeStore &(db::LayoutToNetlist::*) ()) &db::LayoutToNetlist::dss,
+    "@brief Gets a reference to the internal DSS object.\n"
+  ) +
+  gsi::method ("keep_dss", &db::LayoutToNetlist::keep_dss,
+    "@brief Resumes ownership over the DSS object if created with an external one.\n"
+  ) +
   gsi::method ("threads=", &db::LayoutToNetlist::set_threads, gsi::arg ("n"),
     "@brief Sets the number of threads to use for operations which support multiple threads\n"
   ) +
diff --git a/src/drc/drc/built-in-macros/_drc_engine.rb b/src/drc/drc/built-in-macros/_drc_engine.rb
index 0029eb3dd..b02612ab3 100644
--- a/src/drc/drc/built-in-macros/_drc_engine.rb
+++ b/src/drc/drc/built-in-macros/_drc_engine.rb
@@ -20,6 +20,7 @@ module DRC
 
       @def_layout = cv && cv.layout
       @def_cell = cv && cv.cell
+      @def_path = cv && cv.filename
       @def_source = nil
       @dbu_read = false
       use_dbu(@def_layout && @def_layout.dbu)
@@ -27,6 +28,11 @@ module DRC
       @output_rdb = nil
       @output_rdb_file = nil
       @output_rdb_cell = nil
+      @output_l2ndb = nil
+      @output_l2ndb_file = nil
+      @target_netlist_file = nil
+      @target_netlist_format = nil
+      @target_netlist_comment = nil
       @used_output_layers = {}
       @output_layers = []
       @vnum = 1
@@ -109,6 +115,128 @@ module DRC
       DRCAsDots::new(false)
     end
     
+    # %DRC%
+    # @brief Defines SPICE output format (with options) 
+    # @name write_spice
+    # @synopsis write_spice([ use_net_names [, with_comments ] ])
+    # Use this option in \target_netlist for the format parameter to 
+    # specify SPICE format.
+    # "use_net_names" and "with_comments" are boolean parameters indicating
+    # whether to use named nets (numbers if false) and whether to add 
+    # information comments such as instance coordinates or pin names.
+
+    def write_spice(use_net_names = nil, with_comments = nil)
+      writer = RBA::NetlistSpiceWriter::new
+      if use_net_names != nil
+        writer.use_net_names = use_net_names
+      end
+      if with_comments != nil
+        writer.with_comments = with_comments
+      end
+      writer
+    end
+
+    # %DRC%
+    # @brief Supplies the MOS3 transistor extractor class
+    # @name mos3
+    # @synopsis mos3(name)
+    # Use this class with \device_extract to specify extraction of a 
+    # three-terminal MOS transistor
+
+    def mos3(name)
+      RBA::DeviceExtractorMOS3Transistor::new(name)
+    end
+
+    # %DRC%
+    # @brief Supplies the MOS4 transistor extractor class
+    # @name mos4
+    # @synopsis mos4(name)
+    # Use this class with \device_extract to specify extraction of a 
+    # four-terminal MOS transistor
+
+    def mos4(name)
+      RBA::DeviceExtractorMOS4Transistor::new(name)
+    end
+
+    # %DRC%
+    # @brief Supplies the BJT3 transistor extractor class
+    # @name bjt3
+    # @synopsis bjt3(name)
+    # Use this class with \device_extract to specify extraction of a 
+    # bipolar junction transistor
+
+    def bjt3(name)
+      RBA::DeviceExtractorBJT3Transistor::new(name)
+    end
+
+    # %DRC%
+    # @brief Supplies the BJT4 transistor extractor class
+    # @name bjt4
+    # @synopsis bjt4(name)
+    # Use this class with \device_extract to specify extraction of a 
+    # bipolar junction transistor with a substrate terminal
+
+    def bjt4(name)
+      RBA::DeviceExtractorBJT4Transistor::new(name)
+    end
+
+    # %DRC%
+    # @brief Supplies the diode extractor class
+    # @name diode
+    # @synopsis diode(name)
+    # Use this class with \device_extract to specify extraction of a 
+    # planar diode 
+
+    def diode(name)
+      RBA::DeviceExtractorDiode::new(name)
+    end
+
+    # %DRC%
+    # @brief Supplies the resistor extractor class
+    # @name resistor
+    # @synopsis resistor(name, sheet_rho)
+    # Use this class with \device_extract to specify extraction of a resistor.
+    # The sheet_rho value is the sheet resistance in ohms/square.
+
+    def resistor(name, sheet_rho)
+      RBA::DeviceExtractorResistor::new(name, sheet_rho)
+    end
+
+    # %DRC%
+    # @brief Supplies the resistor extractor class that includes a bulk terminal
+    # @name resistor_with_bulk
+    # @synopsis resistor_with_bulk(name)
+    # Use this class with \device_extract to specify extraction of a resistor 
+    # with a bulk terminal.
+    # The sheet_rho value is the sheet resistance in ohms/square.
+
+    def resistor_with_bulk(name, sheet_rho)
+      RBA::DeviceExtractorResistorWithBulk::new(name, sheet_rho)
+    end
+
+    # %DRC%
+    # @brief Supplies the capacitor extractor class
+    # @name capacitor
+    # @synopsis capacitor(name, area_cap)
+    # Use this class with \device_extract to specify extraction of a capacitor.
+    # The area_cap argument is the capacitance in Farad per square micrometer.
+
+    def capacitor(name, area_cap)
+      RBA::DeviceExtractorCapacitor::new(name, area_cap)
+    end
+
+    # %DRC%
+    # @brief Supplies the capacitor extractor class that includes a bulk terminal
+    # @name capacitor_with_bulk
+    # @synopsis capacitor_with_bulk(name)
+    # Use this class with \device_extract to specify extraction of a capacitor 
+    # with a bulk terminal.
+    # The area_cap argument is the capacitance in Farad per square micrometer.
+
+    def capacitor_with_bulk(name, area_cap)
+      RBA::DeviceExtractorCapacitorWithBulk::new(name, area_cap)
+    end
+
     # %DRC%
     # @name verbose?
     # @brief Returns true, if verbose mode is enabled
@@ -451,7 +579,7 @@ module DRC
             (n >= 0 && view.cellviews > n) || raise("Invalid layout index @#{n + 1}")
             cv = view.cellview(n)
             cv.is_valid? || raise("Invalid layout @#{n + 1}")
-            @def_source = make_source(cv.layout, cv.cell)
+            @def_source = make_source(cv.layout, cv.cell, cv.filename)
           else
             layout = RBA::Layout::new
             info("Reading #{arg} ..")
@@ -462,7 +590,7 @@ module DRC
               cell = layout.cell(arg2)
               cell || raise("Cell name #{arg2} not found in input layout")
             end
-            @def_source = make_source(layout, cell)
+            @def_source = make_source(layout, cell, arg)
           end
           
         elsif arg.is_a?(RBA::Layout)
@@ -484,12 +612,13 @@ module DRC
       
       else
         @def_source || @def_layout || raise("No layout loaded - no default layout. Use 'layout' or 'source' to explicitly specify a layout.")
-        @def_source ||= make_source(@def_layout, @def_cell)
+        @def_source ||= make_source(@def_layout, @def_cell, @def_path)
       end
 
       # make default input also default output if none is set yet.
       @def_layout ||= @def_source.layout
       @def_cell ||= @def_source.cell_obj
+      @def_path ||= @def_source.path
           
       # use the DBU of the new input as DBU reference
       @dbu_read || use_dbu(@def_source.layout.dbu)
@@ -545,7 +674,7 @@ module DRC
             (n >= 0 && view.cellviews > n) || raise("Invalid layout index @#{n + 1}")
             cv = view.cellview(n)
             cv.is_valid? || raise("Invalid layout @#{n + 1}")
-            return make_source(cv.layout, cv.cell)
+            return make_source(cv.layout, cv.cell, cv.filename)
           else
             layout = RBA::Layout::new
             info("Reading #{arg} ..")
@@ -556,7 +685,7 @@ module DRC
               cell = layout.cell(arg2)
               cell || raise("Cell name #{arg2} not found in input layout")
             end
-            return make_source(layout, cell)
+            return make_source(layout, cell, arg)
           end
           
         elsif arg.is_a?(RBA::Layout)
@@ -569,7 +698,7 @@ module DRC
       
       else
         @def_source || @def_layout || raise("No layout loaded - no default layout. Use 'layout' or 'source' to explicitly specify a layout.")
-        @def_source ||= make_source(@def_layout, @def_cell)
+        @def_source ||= make_source(@def_layout, @def_cell, @def_path)
         @def_source
       end
           
@@ -627,7 +756,53 @@ module DRC
       @output_rdb.description = description
       
     end
+
+    # %DRC%
+    # @name report_netlist
+    # @brief Specifies an extracted netlist report for output
+    # @synopsis report_netlist([ filename ])
+    # This method applies to runsets creating a netlist through
+    # extraction. Extraction happens when connections and/or device
+    # extractions are made. If this statement is used, the extracted
+    # netlist plus the net and device shapes are turned into a 
+    # layout-to-netlist report (L2N database) and shown in the 
+    # netlist browser window. If a file name is given, the report
+    # will also be written to the given file.
     
+    def report_netlist(filename = nil)
+      @output_l2ndb = true
+      if filename
+        filename.is_a?(String) || raise("Argument must be string in report_netlist")
+      end
+      @output_l2ndb_file = filename
+    end
+
+    # %DRC%
+    # @name target_netlist
+    # @brief With this statement, an extracted netlist is finally written to a file
+    # @synopsis target_netlist(filename [, format [, comment ] ])
+    # This method applies to runsets creating a netlist through
+    # extraction. Extraction happens when connections and/or device
+    # extractions are made. If this statement is used, the extracted
+    # netlist is written to the given file.
+    #
+    # The format parameter specifies the writer to use. You can use nil
+    # to use the standard format or produce a SPICE writer with \write_spice.
+    # See \write_spice for more details.
+    
+    def target_netlist(filename, format = nil, comment = nil)
+      filename.is_a?(String) || raise("First argument must be string in target_netlist")
+      @target_netlist_file = filename
+      if format
+        format.is_a?(RBA::NetlistWriter) || raise("Second argument must be netlist writer object in target_netlist")
+      end
+      @target_netlist_format = format
+      if comment
+        comment.is_a?(String) || raise("Third argument must be string in target_netlist")
+      end
+      @target_netlist_comment = comment
+    end
+
     # %DRC%
     # @name output_cell
     # @brief Specifies a target cell, but does not change the target layout
@@ -958,33 +1133,41 @@ CODE
     # @name clear_connections
     # @brief Clears all connections stored so far
     # @synopsis clear_connections
-    # See \Netter#clear_connections for a description of that function
+    # See \Netter#clear_connections for a description of that function.
 
     # %DRC%
-    # @name join_nets
+    # @name connect_implicit
     # @brief Specifies a label pattern for implicit net connections
-    # @synopsis join_nets(label_pattern)
-    # See \Netter#join_nets for a description of that function
+    # @synopsis connect_implicit(label_pattern)
+    # See \Netter#connect_implicit for a description of that function.
 
     # %DRC%
     # @name antenna_check
     # @brief Performs an antenna check
     # @synopsis antenna_check(gate, metal, ratio, [ diode_specs ... ])
-    # See \Netter#antenna_check for a description of that function
+    # See \Netter#antenna_check for a description of that function.
  
     # %DRC%
     # @name l2n_data
     # @brief Gets the internal RBA::LayoutToNetlist object for the default \Netter
     # @synopsis l2n_data
-    # See \Netter#l2n_data for a description of that function
+    # See \Netter#l2n_data for a description of that function.
  
     # %DRC%
     # @name extract_devices
     # @brief Extracts devices for a given device extractor and device layer selection
     # @synopsis extract_devices(extractor, layer_hash)
-    # See \Netter#extract_devices for a description of that function
+    # @synopsis extract_devices(extractor_class, name, layer_hash)
+    # See \Netter#extract_devices for a description of that function.
  
-    %w(connect connect_global clear_connections join_nets antenna_check l2n_data extract_devices).each do |f|
+    # %DRC%
+    # @name netlist
+    # @brief Obtains the extracted netlist from the default \Netter
+    # The netlist is a RBA::Netlist object. If no netlist is extracted 
+    # yet, this method will trigger the extraction process.
+    # See \Netter#netlist for a description of this function.
+ 
+    %w(connect connect_global clear_connections connect_implicit antenna_check l2n_data extract_devices netlist).each do |f|
       eval <<"CODE"
         def #{f}(*args)
           _netter.#{f}(*args)
@@ -1154,8 +1337,9 @@ CODE
 
       # save the report database if requested
       if @output_rdb_file
-        info("Writing #{@output_rdb_file} ..")
-        @output_rdb.save(@output_rdb_file)
+        rdb_file = make_path(@output_rdb_file)
+        info("Writing report database: #{rdb_file} ..")
+        @output_rdb.save(rdb_file)
       end
       if @output_rdb && final && view
         view.show_rdb(@output_rdb_index, view.active_cellview_index)
@@ -1165,7 +1349,7 @@ CODE
       if @output_layout && @output_layout_file
         opt = RBA::SaveLayoutOptions::new
         gzip = opt.set_format_from_filename(@output_layout_file)
-        info("Writing #{@output_layout_file} ..")
+        info("Writing layout file: #{@output_layout_file} ..")
         @output_layout.write(@output_layout_file, gzip, opt)
       end
       
@@ -1213,7 +1397,41 @@ CODE
         end
         
       end
-        
+
+      # save the netlist if required
+      if @target_netlist_file && @netter && @netter.l2n_data
+
+        writer = @target_netlist_format || RBA::NetlistSpiceWriter::new
+
+        netlist_file = make_path(@target_netlist_file)
+        info("Writing netlist: #{netlist_file} ..")
+        self.netlist.write(netlist_file, writer, @target_netlist_comment || "")
+
+      end
+    
+      # save the netlist database if requested
+      if @output_l2ndb && @netter && @netter.l2n_data
+
+        if @output_l2ndb_file
+          l2ndb_file = make_path(@output_l2ndb_file)
+          info("Writing netlist database: #{l2ndb_file} ..")
+          @netter.l2n_data.save(l2ndb_file)
+        end
+        if @output_l2ndb && final && view
+          # NOTE: to prevent the netter destroying the database, we need to take it
+          l2ndb = @netter._take_l2n_data
+          # we also need to make the extractor take over ownership over the DSS
+          # because otherwise we can't free the resources.
+          if l2ndb.dss == @dss
+            l2ndb.keep_dss
+            @dss = nil
+          end
+          l2ndb_index = view.add_l2ndb(l2ndb)
+          view.show_l2ndb(l2ndb_index, view.active_cellview_index)
+        end
+
+      end
+    
       @output_layout = nil
       @output_layout_file = nil
       @output_cell = nil
@@ -1221,6 +1439,8 @@ CODE
       @output_rdb_cell = nil
       @output_rdb = nil
       @output_rdb_index = nil
+      @output_l2ndb = nil
+      @output_l2ndb_file = nil
 
       # clean up temp data
       @dss && @dss._destroy
@@ -1243,6 +1463,16 @@ CODE
 
   private
 
+    def make_path(file)
+      # resolves the file path relative to the source's path
+      sp = self.source.path
+      if sp
+        return File::absolute_path(file, File::dirname(sp))
+      else
+        return file
+      end
+    end
+
     def _make_string(v)
       if v.class.respond_to?(:from_s)
         v.class.to_s + "::from_s(" + v.to_s.inspect + ")"
@@ -1399,11 +1629,11 @@ CODE
       end        
     end
     
-    def make_source(layout, cell = nil)
+    def make_source(layout, cell = nil, path = nil)
       name = "layout" + @lnum.to_s
       @lnum += 1
       @dbu ||= layout.dbu
-      src = DRCSource::new(self, layout, layout, cell || layout.top_cell)
+      src = DRCSource::new(self, layout, layout, cell || layout.top_cell, path)
       @layout_sources[name] = src
       src
     end
diff --git a/src/drc/drc/built-in-macros/_drc_netter.rb b/src/drc/drc/built-in-macros/_drc_netter.rb
index eed364f48..de07f9413 100644
--- a/src/drc/drc/built-in-macros/_drc_netter.rb
+++ b/src/drc/drc/built-in-macros/_drc_netter.rb
@@ -119,10 +119,14 @@ module DRC
     # @name extract_devices
     # @brief Extracts devices based on the given extractor class, name and device layer selection
     # @synopsis extract_devices(extractor, layer_hash)
-    # Runs the device extraction for given device extractor class.
+    # @synopsis extract_devices(extractor_class, name, layer_hash)
+    # Runs the device extraction for given device extractor class. In the first
+    # form, the extractor object is given. In the second form, the extractor's
+    # class object and the new extractor's name is given.
     # 
     # The device extractor is either an instance of one of the predefined extractor
-    # classes (e.g. RBA::DeviceExtractorMOS4Transistor) or a custom class. It provides the
+    # classes (e.g. obtained from the utility methods such as \mos4) or a custom class. 
+    # It provides the
     # algorithms for deriving the device parameters from the device geometry. It needs 
     # several device recognition layers which are passed in the layer hash.
     #
@@ -141,17 +145,17 @@ module DRC
     # poly    = input(3, 0)
     # bulk    = make_layer   # renders an empty layer used for putting the terminals on
     #
-    # nactive = active - nwell      # active area of NMOS
-    # nsd     = nactive - poly      # source/drain area
+    # nactive = active - nwell  # active area of NMOS
+    # nsd     = nactive - poly  # source/drain area
     # gate    = nactive & poly  # gate area
     #
-    # mos4_ex = RBA::DeviceExtractorMOS4Transistor::new("NMOS4")
-    # extract_devices(mos4_ex, { :SD => nsd, :G => gate, :P => poly, :W => bulk })
+    # extract_devices(mos4("NMOS4"), { :SD => nsd, :G => gate, :P => poly, :W => bulk })
     # @/code
     
     def extract_devices(devex, layer_selection)
 
-      devex.is_a?(RBA::DeviceExtractorBase) || raise("First argument of Netter#extract_devices must be a device extractor instance")
+      devex.is_a?(RBA::DeviceExtractorBase) || raise("First argument of Netter#extract_devices must be a device extractor instance in the two-arguments form")
+
       layer_selection.is_a?(Hash) || raise("Second argument of Netter#extract_devices must be a hash")
 
       ls = {}
@@ -177,20 +181,20 @@ module DRC
       @connections = []
       @global_connections = []
       @layers = {}
-      @join_nets = ""
+      @connect_implicit = ""
       modified
     end
     
     # %DRC%
-    # @name join_nets
+    # @name connect_implicit
     # @brief Specifies a search pattern for labels which create implicit net connections
-    # @synopsis join_nets(label_pattern)
+    # @synopsis connect_implicit(label_pattern)
     # Use this method to supply a glob pattern for labels which create implicit net connections
     # on the top level circuit. This feature is useful to connect identically labelled nets
     # while a component isn't integrated yet. If the component is integrated, net may be connected
     # on a higher hierarchy level - e.g. by a power mesh. Inside the component this net consists
     # of individual islands. To properly perform netlist extraction and comparison, these islands
-    # need to be connected even though there isn't a physical connection. "join_nets" can
+    # need to be connected even though there isn't a physical connection. "connect_implicit" can
     # achive this if these islands are labelled with the same text on the top level of the
     # component.
     #
@@ -202,8 +206,8 @@ module DRC
     # The search pattern is applied on the next net extraction. The search pattern is cleared
     # on "clear_connections".
 
-    def join_nets(arg)
-      @join_nets = arg
+    def connect_implicit(arg)
+      @connect_implicit = arg
       modified
     end
 
@@ -320,6 +324,18 @@ module DRC
       @l2n || make_l2n
       @l2n
     end
+
+    # %DRC%
+    # @name netlist
+    # @brief Gets the extracted netlist or triggers extraction if not done yet
+    # @synopsis netlist
+    # If no extraction has been performed yet, this method will start the 
+    # layout analysis. Hence, all \connect, \connect_global and \connect_implicit
+    # calls must have been made before this method is used. Further \connect
+    # statements will clear the netlist and re-extract it again.
+    def netlist
+      l2n_data && @l2n.netlist
+    end
     
     def _finish
       clear_connections
@@ -327,6 +343,12 @@ module DRC
       modified
     end
 
+    def _take_l2n_data
+      l2ndb = self.l2n_data
+      @l2n = nil
+      l2ndb
+    end
+
   private
 
     def modified
@@ -357,7 +379,7 @@ module DRC
       @global_connections.each { |l,n| @l2n.connect_global(@layers[l], n) }
 
       # run extraction in a timed environment
-      @engine._cmd(@l2n, :extract_netlist, @join_nets)
+      @engine._cmd(@l2n, :extract_netlist, @connect_implicit)
       @l2n
 
     end
diff --git a/src/drc/drc/built-in-macros/_drc_source.rb b/src/drc/drc/built-in-macros/_drc_source.rb
index 90973a7ce..d278d534e 100644
--- a/src/drc/drc/built-in-macros/_drc_source.rb
+++ b/src/drc/drc/built-in-macros/_drc_source.rb
@@ -16,10 +16,11 @@ module DRC
   
   class DRCSource
   
-    def initialize(engine, layout, layout_var, cell)
+    def initialize(engine, layout, layout_var, cell, path)
       @engine = engine
       @layout = layout
       @layout_var = layout_var
+      @path = path
       @cell = cell
       @inside = nil
       @box = nil
@@ -355,6 +356,13 @@ CODE
     def layers
       @layout.layer_indices.collect { |li| @layout.get_info(li) }
     end
+
+    # %DRC%
+    # @brief Gets the path of the corresponding layout file or nil if there is no path
+    # @synopsis path
+    def path
+      @path
+    end
      
   private
 
diff --git a/src/drc/drc/built-in-macros/_drc_tags.rb b/src/drc/drc/built-in-macros/_drc_tags.rb
index 510918dd0..d8f19dfae 100644
--- a/src/drc/drc/built-in-macros/_drc_tags.rb
+++ b/src/drc/drc/built-in-macros/_drc_tags.rb
@@ -111,6 +111,6 @@ module DRC
       end
     end
   end
-    
+
 end
 
diff --git a/src/laybasic/laybasic/layNetlistBrowserPage.cc b/src/laybasic/laybasic/layNetlistBrowserPage.cc
index aeacbebb7..2bcad5d8f 100644
--- a/src/laybasic/laybasic/layNetlistBrowserPage.cc
+++ b/src/laybasic/laybasic/layNetlistBrowserPage.cc
@@ -708,6 +708,11 @@ NetlistBrowserPage::show_all (bool f)
 void
 NetlistBrowserPage::set_db (db::LayoutToNetlist *l2ndb)
 {
+  if (l2ndb == mp_database.get ()) {
+    //  not change
+    return;
+  }
+
   if (mp_info_dialog) {
     delete mp_info_dialog;
     mp_info_dialog = 0;