diff --git a/pcbnew/autorouter/autoplac.cpp b/pcbnew/autorouter/autoplac.cpp
index f943e8116e..16f8b14958 100644
--- a/pcbnew/autorouter/autoplac.cpp
+++ b/pcbnew/autorouter/autoplac.cpp
@@ -440,7 +440,7 @@ int PCB_EDIT_FRAME::GenPlaceBoard()
     m_messagePanel->SetMessage( 14, _( "Cells." ), msg, YELLOW );
 
     /* Choose the number of board sides. */
-    Nb_Sides = TWO_SIDES;
+    RoutingMatrix.m_RoutingLayersCount = 2;
 
     RoutingMatrix.InitRoutingMatrix();
 
@@ -450,7 +450,7 @@ int PCB_EDIT_FRAME::GenPlaceBoard()
 
     Route_Layer_BOTTOM = LAYER_N_FRONT;
 
-    if( Nb_Sides == TWO_SIDES )
+    if( RoutingMatrix.m_RoutingLayersCount > 1 )
         Route_Layer_BOTTOM = LAYER_N_BACK;
 
     Route_Layer_TOP = LAYER_N_FRONT;
@@ -618,7 +618,7 @@ int PCB_EDIT_FRAME::GetOptimalModulePlacement( MODULE* aModule, wxDC* aDC )
      */
     TstOtherSide = false;
 
-    if( Nb_Sides == TWO_SIDES )
+    if( RoutingMatrix.m_RoutingLayersCount > 1 )
     {
         D_PAD* Pad;
         int otherLayerMask = LAYER_BACK;
@@ -967,7 +967,7 @@ void CreateKeepOutRectangle( int ux0, int uy0, int ux1, int uy1,
     if( aLayerMask & GetLayerMask( Route_Layer_BOTTOM ) )
         trace = 1;     /* Trace on bottom layer. */
 
-    if( ( aLayerMask & GetLayerMask( Route_Layer_TOP ) ) && Nb_Sides )
+    if( ( aLayerMask & GetLayerMask( Route_Layer_TOP ) ) && RoutingMatrix.m_RoutingLayersCount )
         trace |= 2;    /* Trace on top layer. */
 
     if( trace == 0 )
diff --git a/pcbnew/autorouter/autorout.cpp b/pcbnew/autorouter/autorout.cpp
index 4819575575..7ea56d1768 100644
--- a/pcbnew/autorouter/autorout.cpp
+++ b/pcbnew/autorouter/autorout.cpp
@@ -47,12 +47,6 @@
 #include <autorout.h>
 
 
-int Nb_Sides;        /* Number of layer for autorouting (0 or 1) */
-int OpenNodes;       /* total number of nodes opened */
-int ClosNodes;       /* total number of nodes closed */
-int MoveNodes;       /* total number of nodes moved */
-int MaxNodes;        /* maximum number of nodes opened at one time */
-
 MATRIX_ROUTING_HEAD RoutingMatrix;     // routing matrix (grid) to route 2-sided boards
 
 /* init board, route traces*/
@@ -175,10 +169,10 @@ void PCB_EDIT_FRAME::Autoroute( wxDC* DC, int mode )
     m_messagePanel->EraseMsgBox();
 
     /* Map the board */
-    Nb_Sides = ONE_SIDE;
+    RoutingMatrix.m_RoutingLayersCount = 1;
 
     if( Route_Layer_TOP != Route_Layer_BOTTOM )
-        Nb_Sides = TWO_SIDES;
+        RoutingMatrix.m_RoutingLayersCount = 2;
 
     if( RoutingMatrix.InitRoutingMatrix() < 0 )
     {
@@ -195,10 +189,7 @@ void PCB_EDIT_FRAME::Autoroute( wxDC* DC, int mode )
 
     // DisplayRoutingMatrix( m_canvas, DC );
 
-    if( Nb_Sides == TWO_SIDES )
-        Solve( DC, TWO_SIDES ); /* double face */
-    else
-        Solve( DC, ONE_SIDE );  /* simple face */
+    Solve( DC, RoutingMatrix.m_RoutingLayersCount );
 
     /* Free memory. */
     FreeQueue();
@@ -249,7 +240,7 @@ void DisplayRoutingMatrix( EDA_DRAW_PANEL* panel, wxDC* DC )
             if( dcell0 & HOLE )
                 color = GREEN;
 
-//            if( Nb_Sides )
+//            if( RoutingMatrix.m_RoutingLayersCount )
 //                dcell1 = GetCell( row, col, TOP );
 
             if( dcell1 & HOLE )
diff --git a/pcbnew/autorouter/autorout.h b/pcbnew/autorouter/autorout.h
index c6c01f431d..baa2074c65 100644
--- a/pcbnew/autorouter/autorout.h
+++ b/pcbnew/autorouter/autorout.h
@@ -46,7 +46,8 @@ class BOARD;
 
 
 /* Autorouter commands. */
-enum CommandOpt {
+enum AUTOPLACEROUTE_OPTIONS
+{
     PLACE_ALL,
     PLACE_OUT_OF_BOARD,
     PLACE_INCREMENTAL,
@@ -58,13 +59,7 @@ enum CommandOpt {
     ROUTE_PAD
 };
 
-
-#define ONE_SIDE  0
-#define TWO_SIDES 1
-
-#define MAX_SIDES_COUNT 2
-
-extern int Nb_Sides;    /* Number of layers for autorouting (0 or 1) */
+#define MAX_ROUTING_LAYERS_COUNT 2
 
 #define FORCE_PADS 1  /* Force placement of pads for any Netcode */
 
@@ -88,20 +83,23 @@ typedef char DIR_CELL;
 class MATRIX_ROUTING_HEAD
 {
 public:
-    MATRIX_CELL* m_BoardSide[MAX_SIDES_COUNT];  // the image map of 2 board sides
-    DIST_CELL*   m_DistSide[MAX_SIDES_COUNT];   // the image map of 2 board sides: distance to
-                                                // cells
-    DIR_CELL*    m_DirSide[MAX_SIDES_COUNT];    // the image map of 2 board sides: pointers back to
-                                                // source
+    MATRIX_CELL* m_BoardSide[MAX_ROUTING_LAYERS_COUNT]; // the image map of 2 board sides
+    DIST_CELL*   m_DistSide[MAX_ROUTING_LAYERS_COUNT];  // the image map of 2 board sides:
+                                                        // distance to cells
+    DIR_CELL*    m_DirSide[MAX_ROUTING_LAYERS_COUNT];   // the image map of 2 board sides:
+                                                        // pointers back to source
     bool         m_InitMatrixDone;
-    int          m_Layers;                      // Layer count (1 2 )
+    int          m_RoutingLayersCount;          // Number of layers for autorouting (0 or 1)
     int          m_GridRouting;                 // Size of grid for autoplace/autoroute
     EDA_RECT     m_BrdBox;                      // Actual board bounding box
     int          m_Nrows, m_Ncols;              // Matrix size
     int          m_MemSize;                     // Memory requirement, just for statistics
     int          m_RouteCount;                  // Number of routes
+
 private:
-    void        (MATRIX_ROUTING_HEAD::* m_opWriteCell)( int aRow, int aCol, int aSide, MATRIX_CELL aCell);  // a pointeur to the current selected cell op
+    // a pointer to the current selected cell operation
+    void        (MATRIX_ROUTING_HEAD::* m_opWriteCell)( int aRow, int aCol,
+                                                        int aSide, MATRIX_CELL aCell);
 
 public:
     MATRIX_ROUTING_HEAD();
@@ -114,7 +112,7 @@ public:
 
     /**
      * function GetBrdCoordOrigin
-     * @returns the board coordinate corresponding to the
+     * @return the board coordinate corresponding to the
      * routing matrix origin ( board coordinate offset )
      */
     wxPoint GetBrdCoordOrigin()
@@ -156,6 +154,12 @@ public:
     void SetDist( int aRow, int aCol, int aSide, DIST_CELL );
     int GetDir( int aRow, int aCol, int aSide );
     void SetDir( int aRow, int aCol, int aSide, int aDir);
+
+    // calculate distance (with penalty) of a trace through a cell
+    int CalcDist(int x,int y,int z ,int side );
+
+    // calculate approximate distance (manhattan distance)
+    int GetApxDist( int r1, int c1, int r2, int c2 );
 };
 
 extern MATRIX_ROUTING_HEAD RoutingMatrix;        /* 2-sided board */
@@ -220,10 +224,6 @@ int SetWork( int, int, int , int, int, RATSNEST_ITEM *, int );
 void GetWork( int *, int *, int *, int *, int *, RATSNEST_ITEM ** );
 void SortWork(); /* order the work items; shortest first */
 
-/* DIST.CPP */
-int GetApxDist( int r1, int c1, int r2, int c2 );
-int CalcDist(int x,int y,int z ,int side );
-
 /* routing_matrix.cpp */
 int Build_Work( BOARD * Pcb );
 void PlaceCells( BOARD * Pcb, int net_code, int flag = 0 );
diff --git a/pcbnew/autorouter/dist.cpp b/pcbnew/autorouter/dist.cpp
index 8bc91921cf..5841073aad 100644
--- a/pcbnew/autorouter/dist.cpp
+++ b/pcbnew/autorouter/dist.cpp
@@ -39,7 +39,7 @@
 
  /* calculate approximate distance (manhattan distance)
  */
-int GetApxDist( int r1, int c1, int r2, int c2 )
+int MATRIX_ROUTING_HEAD::GetApxDist( int r1, int c1, int r2, int c2 )
 {
     int d1, d2; /* row and column deltas */
 
@@ -135,7 +135,7 @@ static int dir_penalty_BOTTOM[10][10] =
 
 /* calculate distance (with penalty) of a trace through a cell
 */
-int CalcDist(int x,int y,int z ,int side )
+int MATRIX_ROUTING_HEAD::CalcDist(int x,int y,int z ,int side  )
 {
     int adjust, ldist;
 
@@ -158,7 +158,7 @@ int CalcDist(int x,int y,int z ,int side )
 
     ldist = dist[x-1][y-1] + penalty[x-1][y-1] + adjust;
 
-    if( Nb_Sides )
+    if( m_RouteCount > 1 )
     {
         if( side == BOTTOM )
             ldist += dir_penalty_TOP[x-1][y-1];
diff --git a/pcbnew/autorouter/graphpcb.cpp b/pcbnew/autorouter/graphpcb.cpp
index 77d137ab55..ede59ae1c9 100644
--- a/pcbnew/autorouter/graphpcb.cpp
+++ b/pcbnew/autorouter/graphpcb.cpp
@@ -71,14 +71,14 @@ static void TraceCircle( int ux0, int uy0, int ux1, int uy1, int lg, int layer,
         if( layer < 0 )                                                 \
         {                                                               \
             RoutingMatrix.WriteCell( dy, dx, BOTTOM, color );           \
-            if( Nb_Sides )                                              \
+            if( RoutingMatrix.m_RoutingLayersCount > 1 )                                              \
                 RoutingMatrix.WriteCell( dy, dx, TOP, color );                        \
         }                                                               \
         else                                                            \
         {                                                               \
             if( layer == Route_Layer_BOTTOM )                           \
                 RoutingMatrix.WriteCell( dy, dx, BOTTOM, color );       \
-            if( Nb_Sides )                                              \
+            if( RoutingMatrix.m_RoutingLayersCount > 1 )                                              \
                 if( layer == Route_Layer_TOP )                          \
                     RoutingMatrix.WriteCell( dy, dx, TOP, color );      \
         }                                                               \
@@ -156,7 +156,7 @@ void TraceFilledCircle( int    cx, int cy, int radius,
         trace = 1;       // Trace on BOTTOM
 
     if( aLayerMask & GetLayerMask( Route_Layer_TOP ) )
-        if( Nb_Sides )
+        if( RoutingMatrix.m_RoutingLayersCount > 1 )
             trace |= 2;  // Trace on TOP
 
     if( trace == 0 )
@@ -475,7 +475,7 @@ void TraceFilledRectangle( int ux0, int uy0, int ux1, int uy1,
     if( ( aLayerMask & GetLayerMask( Route_Layer_BOTTOM ) ) )
         trace = 1;     // Trace on BOTTOM
 
-    if( ( aLayerMask & GetLayerMask( Route_Layer_TOP ) ) && Nb_Sides )
+    if( ( aLayerMask & GetLayerMask( Route_Layer_TOP ) ) && RoutingMatrix.m_RoutingLayersCount > 1 )
         trace |= 2;    // Trace on TOP
 
     if( trace == 0 )
@@ -542,7 +542,7 @@ void TraceFilledRectangle( int ux0, int uy0, int ux1, int uy1,
 
     if( aLayerMask & GetLayerMask( Route_Layer_TOP ) )
     {
-        if( Nb_Sides )
+        if( RoutingMatrix.m_RoutingLayersCount > 1 )
             trace |= 2;  // Trace on TOP
     }
 
diff --git a/pcbnew/autorouter/routing_matrix.cpp b/pcbnew/autorouter/routing_matrix.cpp
index e48c35ab37..e9ac66eef9 100644
--- a/pcbnew/autorouter/routing_matrix.cpp
+++ b/pcbnew/autorouter/routing_matrix.cpp
@@ -46,6 +46,23 @@
 #include <class_pcb_text.h>
 
 
+MATRIX_ROUTING_HEAD::MATRIX_ROUTING_HEAD()
+{
+    m_BoardSide[0]   = m_BoardSide[1] = NULL;
+    m_DistSide[0]    = m_DistSide[1] = NULL;
+    m_DirSide[0]     = m_DirSide[1] = NULL;
+    m_InitMatrixDone = false;
+    m_Nrows   = m_Ncols = 0;
+    m_MemSize = 0;
+    m_RoutingLayersCount = 1;
+}
+
+
+MATRIX_ROUTING_HEAD::~MATRIX_ROUTING_HEAD()
+{
+}
+
+
 bool MATRIX_ROUTING_HEAD::ComputeMatrixSize( BOARD* aPcb, bool aUseBoardEdgesOnly )
 {
     aPcb->ComputeBoundingBox( aUseBoardEdgesOnly );
@@ -80,22 +97,6 @@ bool MATRIX_ROUTING_HEAD::ComputeMatrixSize( BOARD* aPcb, bool aUseBoardEdgesOnl
 }
 
 
-MATRIX_ROUTING_HEAD::MATRIX_ROUTING_HEAD()
-{
-    m_BoardSide[0]   = m_BoardSide[1] = NULL;
-    m_DistSide[0]    = m_DistSide[1] = NULL;
-    m_DirSide[0]     = m_DirSide[1] = NULL;
-    m_InitMatrixDone = false;
-    m_Layers  = MAX_SIDES_COUNT;
-    m_Nrows   = m_Ncols = 0;
-    m_MemSize = 0;
-}
-
-
-MATRIX_ROUTING_HEAD::~MATRIX_ROUTING_HEAD()
-{
-}
-
 
 int MATRIX_ROUTING_HEAD::InitRoutingMatrix()
 {
@@ -109,7 +110,7 @@ int MATRIX_ROUTING_HEAD::InitRoutingMatrix()
     // give a small margin for memory allocation:
    ii = (RoutingMatrix.m_Nrows + 1) * (RoutingMatrix.m_Ncols + 1);
 
-    for( kk = 0; kk < m_Layers; kk++ )
+    for( kk = 0; kk < m_RoutingLayersCount; kk++ )
     {
         m_BoardSide[kk] = NULL;
         m_DistSide[kk]  = NULL;
@@ -137,7 +138,7 @@ int MATRIX_ROUTING_HEAD::InitRoutingMatrix()
             return -1;
     }
 
-    m_MemSize = m_Layers * ii * ( sizeof(MATRIX_CELL) + sizeof(DIST_CELL) + sizeof(char) );
+    m_MemSize = m_RouteCount * ii * ( sizeof(MATRIX_CELL) + sizeof(DIST_CELL) + sizeof(char) );
 
     return m_MemSize;
 }
@@ -149,7 +150,7 @@ void MATRIX_ROUTING_HEAD::UnInitRoutingMatrix()
 
     m_InitMatrixDone = false;
 
-    for( ii = 0; ii < MAX_SIDES_COUNT; ii++ )
+    for( ii = 0; ii < MAX_ROUTING_LAYERS_COUNT; ii++ )
     {
         // de-allocate Dir matrix
         if( m_DirSide[ii] )
@@ -179,14 +180,17 @@ void MATRIX_ROUTING_HEAD::UnInitRoutingMatrix()
 
 /**
  * Function PlaceCells
- * initializes the cell board is set and VIA_IMPOSSIBLE HOLE according to the setbacks.
- * The elements of net_code = net_code will not be occupied as places but only
- * VIA_IMPOSSIBLE
- * For single-sided Routing 1:
- * BOTTOM side is used and Route_Layer_BOTTOM = Route_Layer_TOP
+ * Initialize the matrix routing by setting obstacles for each occupied cell
+ * a cell set to HOLE is an obstacle for tracks and vias
+ * a cell set to VIA_IMPOSSIBLE is an obstacle for vias only.
+ * a cell set to CELL_is_EDGE is a frontier.
+ * Tracks and vias having the same net code as net_code are skipped
+ * (htey do not are obstacles)
  *
- * According to the bits = 1 parameter flag:
- * If FORCE_PADS: all pads will be placed even those same net_code.
+ * For single-sided Routing 1:
+ * BOTTOM side is used, and Route_Layer_BOTTOM = Route_Layer_TOP
+ *
+ * If flag == FORCE_PADS: all pads will be put in matrix as obstacles.
  */
 void PlaceCells( BOARD* aPcb, int net_code, int flag )
 {
@@ -347,8 +351,6 @@ int Build_Work( BOARD* Pcb )
     int             demi_pas = RoutingMatrix.m_GridRouting / 2;
     wxString        msg;
 
-    EDA_RECT        bbbox = Pcb->GetBoundingBox();
-
     InitWork(); /* clear work list */
     int cellCount = 0;
 
@@ -356,7 +358,7 @@ int Build_Work( BOARD* Pcb )
     {
         pt_rats = &Pcb->m_FullRatsnest[ii];
 
-        /* We consider her only ratsnest that are active ( obviously not yet routed)
+        /* We consider here only ratsnest that are active ( obviously not yet routed)
          * and routables (that are not yet attempt to be routed and fail
          */
         if( (pt_rats->m_Status & CH_ACTIF) == 0 )
@@ -373,45 +375,47 @@ int Build_Work( BOARD* Pcb )
         current_net_code = pt_pad->GetNet();
         pt_ch = pt_rats;
 
-        r1 = ( pt_pad->GetPosition().y - bbbox.GetY() + demi_pas ) / RoutingMatrix.m_GridRouting;
+        r1 = ( pt_pad->GetPosition().y - RoutingMatrix.m_BrdBox.GetY() + demi_pas )
+            / RoutingMatrix.m_GridRouting;
 
         if( r1 < 0 || r1 >= RoutingMatrix.m_Nrows )
         {
             msg.Printf( wxT( "error : row = %d ( padY %d pcbY %d) " ), r1,
-                        pt_pad->GetPosition().y, bbbox.GetY() );
+                        pt_pad->GetPosition().y, RoutingMatrix.m_BrdBox.GetY() );
             wxMessageBox( msg );
             return 0;
         }
 
-        c1 = ( pt_pad->GetPosition().x - bbbox.GetX() + demi_pas ) / RoutingMatrix.m_GridRouting;
+        c1 = ( pt_pad->GetPosition().x - RoutingMatrix.m_BrdBox.GetX() + demi_pas ) / RoutingMatrix.m_GridRouting;
 
         if( c1 < 0 || c1 >= RoutingMatrix.m_Ncols )
         {
             msg.Printf( wxT( "error : col = %d ( padX %d pcbX %d) " ), c1,
-                        pt_pad->GetPosition().x, bbbox.GetX() );
+                        pt_pad->GetPosition().x, RoutingMatrix.m_BrdBox.GetX() );
             wxMessageBox( msg );
             return 0;
         }
 
         pt_pad = pt_rats->m_PadEnd;
 
-        r2 = ( pt_pad->GetPosition().y - bbbox.GetY()
+        r2 = ( pt_pad->GetPosition().y - RoutingMatrix.m_BrdBox.GetY()
                + demi_pas ) / RoutingMatrix.m_GridRouting;
 
         if( r2 < 0 || r2 >= RoutingMatrix.m_Nrows )
         {
             msg.Printf( wxT( "error : row = %d ( padY %d pcbY %d) " ), r2,
-                        pt_pad->GetPosition().y, bbbox.GetY() );
+                        pt_pad->GetPosition().y, RoutingMatrix.m_BrdBox.GetY() );
             wxMessageBox( msg );
             return 0;
         }
 
-        c2 = ( pt_pad->GetPosition().x - bbbox.GetX() + demi_pas ) / RoutingMatrix.m_GridRouting;
+        c2 = ( pt_pad->GetPosition().x - RoutingMatrix.m_BrdBox.GetX() + demi_pas )
+             / RoutingMatrix.m_GridRouting;
 
         if( c2 < 0 || c2 >= RoutingMatrix.m_Ncols )
         {
             msg.Printf( wxT( "error : col = %d ( padX %d pcbX %d) " ), c2,
-                        pt_pad->GetPosition().x, bbbox.GetX() );
+                        pt_pad->GetPosition().x, RoutingMatrix.m_BrdBox.GetX() );
             wxMessageBox( msg );
             return 0;
         }
@@ -424,7 +428,7 @@ int Build_Work( BOARD* Pcb )
     return cellCount;
 }
 
-// Initialize WriteCell to make the aLogicOp
+// Initialize m_opWriteCell member to make the aLogicOp
 void MATRIX_ROUTING_HEAD::SetCellOperation( int aLogicOp )
 {
     switch( aLogicOp )
diff --git a/pcbnew/autorouter/solve.cpp b/pcbnew/autorouter/solve.cpp
index 8ef2af3e7d..c3c00a2c0a 100644
--- a/pcbnew/autorouter/solve.cpp
+++ b/pcbnew/autorouter/solve.cpp
@@ -86,6 +86,10 @@ static int            s_Clearance;  // Clearance value used in autorouter
 
 static PICKED_ITEMS_LIST s_ItemsListPicker;
 
+int OpenNodes;       /* total number of nodes opened */
+int ClosNodes;       /* total number of nodes closed */
+int MoveNodes;       /* total number of nodes moved */
+int MaxNodes;        /* maximum number of nodes opened at one time */
 
 #define NOSUCCESS       0
 #define STOP_FROM_ESC   -1
@@ -263,7 +267,7 @@ static long newmask[8] =
  * -1 if escape (stop being routed) request
  * -2 if default memory allocation
  */
-int PCB_EDIT_FRAME::Solve( wxDC* DC, int two_sides )
+int PCB_EDIT_FRAME::Solve( wxDC* DC, int aLayersCount )
 {
     int           current_net_code;
     int           row_source, col_source, row_target, col_target;
@@ -272,6 +276,7 @@ int PCB_EDIT_FRAME::Solve( wxDC* DC, int two_sides )
     bool          stop = false;
     wxString      msg;
     int           routedCount = 0;      // routed ratsnest count
+    bool          two_sides = aLayersCount == 2;
 
     m_canvas->SetAbortRequest( false );
 
@@ -522,7 +527,7 @@ static int Autoroute_One_Track( PCB_EDIT_FRAME* pcbframe,
     }
 
     InitQueue(); /* initialize the search queue */
-    apx_dist = GetApxDist( row_source, col_source, row_target, col_target );
+    apx_dist = RoutingMatrix.GetApxDist( row_source, col_source, row_target, col_target );
 
     /* Initialize first search. */
     if( two_sides )   /* Preferred orientation. */
@@ -713,7 +718,7 @@ static int Autoroute_One_Track( PCB_EDIT_FRAME* pcbframe,
             }
 
             olddir  = RoutingMatrix.GetDir( r, c, side );
-            newdist = d + CalcDist( ndir[i], olddir,
+            newdist = d + RoutingMatrix.CalcDist( ndir[i], olddir,
                                     ( olddir == FROM_OTHERSIDE ) ?
                                     RoutingMatrix.GetDir( r, c, 1 - side ) : 0, side );
 
@@ -725,7 +730,7 @@ static int Autoroute_One_Track( PCB_EDIT_FRAME* pcbframe,
                 RoutingMatrix.SetDist( nr, nc, side, newdist );
 
                 if( SetQueue( nr, nc, side, newdist,
-                              GetApxDist( nr, nc, row_target, col_target ),
+                              RoutingMatrix.GetApxDist( nr, nc, row_target, col_target ),
                               row_target, col_target ) == 0 )
                 {
                     return ERR_MEMORY;
@@ -736,7 +741,7 @@ static int Autoroute_One_Track( PCB_EDIT_FRAME* pcbframe,
                 RoutingMatrix.SetDir( nr, nc, side, ndir[i] );
                 RoutingMatrix.SetDist( nr, nc, side, newdist );
                 ReSetQueue( nr, nc, side, newdist,
-                            GetApxDist( nr, nc, row_target, col_target ),
+                            RoutingMatrix.GetApxDist( nr, nc, row_target, col_target ),
                             row_target, col_target );
             }
         }
@@ -781,7 +786,7 @@ static int Autoroute_One_Track( PCB_EDIT_FRAME* pcbframe,
             if( skip )      /* neighboring hole or trace? */
                 continue;   /* yes, can't drill via here */
 
-            newdist = d + CalcDist( FROM_OTHERSIDE, olddir, 0, side );
+            newdist = d + RoutingMatrix.CalcDist( FROM_OTHERSIDE, olddir, 0, side );
 
             /*  if (a) not visited yet,
              *  or (b) we have found a better path,
diff --git a/pcbnew/autorouter/work.cpp b/pcbnew/autorouter/work.cpp
index 0db5dad007..11d0f1841b 100644
--- a/pcbnew/autorouter/work.cpp
+++ b/pcbnew/autorouter/work.cpp
@@ -41,9 +41,9 @@
 #include <cell.h>
 
 
-struct CWORK    // a unit of work is a source-target (a ratsnet item) to connect
+struct CWORK    // a unit of work is a source-target to connect
+                // this is a ratsnest item in the routing matrix world
 {
-    struct CWORK*   m_Next;
     int             m_FromRow;      // source row
     int             m_FromCol;      // source column
     int             m_ToRow;        // target row
@@ -53,34 +53,22 @@ struct CWORK    // a unit of work is a source-target (a ratsnet item) to connect
     int             m_ApxDist;      // approximate distance
     int             m_Cost;         // cost for sort by length
     int             m_Priority;     // route priority
+
+    // the function that calculates the cost of this ratsnest:
+    void CalculateCost();
 };
 
 
-// pointers to the first and last item of work to do
-static CWORK*   Head    = NULL;
-static CWORK*   Tail    = NULL;
-static CWORK*   Current = NULL;
+// the list of ratsnests
+static std::vector <CWORK> WorkList;
+static unsigned Current = 0;
 
 
 // initialize the work list
 void InitWork()
 {
-    CWORK* ptr;
-
-    while( ( ptr = Head ) != NULL )
-    {
-        Head = ptr->m_Next;
-        delete ptr;
-    }
-
-    Tail = Current = NULL;
-}
-
-
-// initialize the work list
-void ReInitWork()
-{
-    Current = Head;
+    WorkList.clear();
+    Current = 0;
 }
 
 
@@ -89,40 +77,24 @@ void ReInitWork()
  *  1 if OK
  *  0 if memory allocation failed
  */
-static int GetCost( int r1, int c1, int r2, int c2 );
 
 int SetWork( int r1, int c1,
              int n_c,
              int r2, int c2,
              RATSNEST_ITEM* pt_ch, int pri )
 {
-    CWORK* p;
-
-    if( ( p = (CWORK*) operator new( sizeof(CWORK), std::nothrow ) ) != NULL )
-    {
-        p->m_FromRow    = r1;
-        p->m_FromCol    = c1;
-        p->m_NetCode    = n_c;
-        p->m_ToRow      = r2;
-        p->m_ToCol      = c2;
-        p->m_Ratsnest   = pt_ch;
-        p->m_ApxDist    = GetApxDist( r1, c1, r2, c2 );
-        p->m_Cost       = GetCost( r1, c1, r2, c2 );
-        p->m_Priority   = pri;
-        p->m_Next       = NULL;
-
-        if( Head )  /* attach at end */
-            Tail->m_Next = p;
-        else        /* first in list */
-            Head = Current = p;
-
-        Tail = p;
-        return 1;
-    }
-    else    /* can't get any more memory */
-    {
-        return 0;
-    }
+    CWORK item;
+    item.m_FromRow    = r1;
+    item.m_FromCol    = c1;
+    item.m_NetCode    = n_c;
+    item.m_ToRow      = r2;
+    item.m_ToCol      = c2;
+    item.m_Ratsnest   = pt_ch;
+    item.m_ApxDist    = RoutingMatrix.GetApxDist( r1, c1, r2, c2 );
+    item.CalculateCost();
+    item.m_Priority   = pri;
+    WorkList.push_back( item );
+    return 1;
 }
 
 
@@ -132,15 +104,15 @@ void GetWork( int* r1, int* c1,
               int* r2, int* c2,
               RATSNEST_ITEM** pt_ch )
 {
-    if( Current )
+    if( Current < WorkList.size() )
     {
-        *r1     = Current->m_FromRow;
-        *c1     = Current->m_FromCol;
-        *n_c    = Current->m_NetCode;
-        *r2     = Current->m_ToRow;
-        *c2     = Current->m_ToCol;
-        *pt_ch  = Current->m_Ratsnest;
-        Current = Current->m_Next;
+        *r1     = WorkList[Current].m_FromRow;
+        *c1     = WorkList[Current].m_FromCol;
+        *n_c    = WorkList[Current].m_NetCode;
+        *r2     = WorkList[Current].m_ToRow;
+        *c2     = WorkList[Current].m_ToCol;
+        *pt_ch  = WorkList[Current].m_Ratsnest;
+        Current++;
     }
     else    /* none left */
     {
@@ -151,64 +123,18 @@ void GetWork( int* r1, int* c1,
 }
 
 
-/* order the work items; shortest (low cost) first */
+// order the work items; shortest (low cost) first:
+bool sort_by_cost( const CWORK& ref, const CWORK& item )
+{
+    if( ref.m_Priority == item.m_Priority )
+        return ref.m_Cost < item.m_Cost;
+
+    return ref.m_Priority >= item.m_Priority;
+}
+
 void SortWork()
 {
-    CWORK*  p;
-    CWORK*  q0; /* put PRIORITY PAD_CONNECTs in q0 */
-    CWORK*  q1; /* sort other PAD_CONNECTs in q1 */
-    CWORK*  r;
-
-    q0 = q1 = NULL;
-
-    while( (p = Head) != NULL )    /* prioritize each work item */
-    {
-        Head = Head->m_Next;
-
-        if( p->m_Priority )    /* put at end of priority list */
-        {
-            p->m_Next = NULL;
-
-            if( (r = q0) == NULL )    /* empty list? */
-            {
-                q0 = p;
-            }
-            else                    /* attach at end */
-            {
-                while( r->m_Next )  /* search for end */
-                    r = r->m_Next;
-
-                r->m_Next = p;    /* attach */
-            }
-        }
-        else if( ( ( r = q1 ) == NULL ) || ( p->m_Cost < q1->m_Cost ) )
-        {
-            p->m_Next = q1;
-            q1 = p;
-        }
-        else    /* find proper position in list */
-        {
-            while( r->m_Next && p->m_Cost >= r->m_Next->m_Cost )
-                r = r->m_Next;
-
-            p->m_Next   = r->m_Next;
-            r->m_Next   = p;
-        }
-    }
-
-    if( (p = q0) != NULL )    /* any priority PAD_CONNECTs? */
-    {
-        while( q0->m_Next )
-            q0 = q0->m_Next;
-
-        q0->m_Next = q1;
-    }
-    else
-        p = q1;
-
-    /* reposition Head and Tail */
-    for( Head = Current = Tail = p; Tail && Tail->m_Next; Tail = Tail->m_Next )
-        ;
+    sort( WorkList.begin(), WorkList.end(), sort_by_cost );
 }
 
 
@@ -216,13 +142,13 @@ void SortWork()
  *   cost = (| dx | + | dy |) * disability
  *   disability = 1 if dx or dy = 0, max if | dx | # | dy |
  */
-static int GetCost( int r1, int c1, int r2, int c2 )
+void CWORK::CalculateCost()
 {
     int     dx, dy, mx, my;
     double  incl = 1.0;
 
-    dx  = abs( c2 - c1 );
-    dy  = abs( r2 - r1 );
+    dx  = abs( m_ToCol - m_FromCol );
+    dy  = abs( m_ToRow - m_FromRow );
     mx  = dx;
     my  = dy;
 
@@ -234,5 +160,5 @@ static int GetCost( int r1, int c1, int r2, int c2 )
     if( mx )
         incl += (2 * (double) my / mx);
 
-    return (int) ( ( dx + dy ) * incl );
+    m_Cost = (int) ( ( dx + dy ) * incl );
 }
diff --git a/pcbnew/kicad_plugin.cpp b/pcbnew/kicad_plugin.cpp
index 5ff61d02da..c7e127ea2a 100644
--- a/pcbnew/kicad_plugin.cpp
+++ b/pcbnew/kicad_plugin.cpp
@@ -1204,7 +1204,9 @@ BOARD* PCB_IO::Load( const wxString& aFileName, BOARD* aAppendToMe, PROPERTIES*
 
     if( !file.IsOpened() )
     {
-        THROW_IO_ERROR( _( "Unable to read file \"" ) + aFileName + wxT( "\"" ) );
+        wxString msg;
+        msg.Printf( _( "Unable to read file \"%s\"" ), GetChars( aFileName ) );
+        THROW_IO_ERROR( msg );
     }
 
     PCB_PARSER parser( new FILE_LINE_READER( file.fp(), aFileName ), aAppendToMe );
diff --git a/pcbnew/pcb_parser.cpp b/pcbnew/pcb_parser.cpp
index b860f52b4c..9676a7925d 100644
--- a/pcbnew/pcb_parser.cpp
+++ b/pcbnew/pcb_parser.cpp
@@ -319,7 +319,7 @@ BOARD_ITEM* PCB_PARSER::Parse() throw( IO_ERROR, PARSE_ERROR )
 
     default:
         wxString err;
-        err.Printf( _( "unknown token \"%s\" " ), GetChars( FromUTF8() ) );
+        err.Printf( _( "unknown token \"%s\"" ), GetChars( FromUTF8() ) );
         THROW_PARSE_ERROR( err, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
     }