diff --git a/demo/ecma119_tree.c b/demo/ecma119_tree.c
index 45bd5d4..dc500cd 100644
--- a/demo/ecma119_tree.c
+++ b/demo/ecma119_tree.c
@@ -95,7 +95,7 @@ int main(int argc, char **argv)
     ecma119->image = image;
 	
     /* create low level tree */
-    result = ecma119_tree_create(ecma119, iso_image_get_root(image));
+    result = ecma119_tree_create(ecma119);
     if (result < 0) {
         printf ("Error creating ecma-119 tree: %d\n", result);
         return 1;
diff --git a/src/ecma119.c b/src/ecma119.c
index c70ebae..45c0a0a 100644
--- a/src/ecma119.c
+++ b/src/ecma119.c
@@ -19,11 +19,87 @@
 #include <stdlib.h>
 #include <time.h>
 
+static
+void ecma119_image_free(Ecma119Image *t)
+{
+    size_t i;
+    
+    ecma119_node_free(t->root);
+    iso_image_unref(t->image);
+    iso_file_src_free(t);
+    
+    for (i = 0; i < t->nwriters; ++i) {
+        IsoImageWriter *writer = t->writers[i];
+        writer->free_data(writer);
+        free(writer);
+    }
+    free(t->writers);
+    free(t);
+}
+
+static
+int ecma119_writer_compute_data_blocks(IsoImageWriter *writer)
+{
+    //TODO to implement
+    return -1;
+}
+
+static
+int ecma119_writer_write_vol_desc(IsoImageWriter *writer)
+{
+    //TODO to implement
+    return -1;
+}
+
+static
+int ecma119_writer_write_data(IsoImageWriter *writer)
+{
+    //TODO to implement
+    return -1;
+}
+
+static
+int ecma119_writer_free_data(IsoImageWriter *writer)
+{
+    //TODO to implement
+    return -1;
+}
+
+int ecma119_writer_create(Ecma119Image *target)
+{
+    int ret;
+    IsoImageWriter *writer;
+    
+    writer = malloc(sizeof(IsoImageWriter));
+    if (writer == NULL) {
+        return ISO_MEM_ERROR;
+    }
+    
+    writer->compute_data_blocks = ecma119_writer_compute_data_blocks;
+    writer->write_vol_desc = ecma119_writer_write_vol_desc;
+    writer->write_data = ecma119_writer_write_data;
+    writer->free_data = ecma119_writer_free_data;
+    writer->data = NULL;
+    writer->target = target;
+    
+    /* add this writer to image */
+    target->writers[target->nwriters++] = writer;
+    
+    ret = ecma119_tree_create(target);
+    if (ret < 0) {
+        return ret;
+    }
+    
+    /* we need the volume descriptor */
+    target->curblock++;
+    return ISO_SUCCESS;
+}
+
 static 
 int ecma119_image_new(IsoImage *src, Ecma119WriteOpts *opts, 
                       Ecma119Image **img)
 {
-    int ret;
+    int ret, i;
     Ecma119Image *target;
     
     /* 1. Allocate target and copy opts there */
@@ -33,16 +109,12 @@ int ecma119_image_new(IsoImage *src, Ecma119WriteOpts *opts,
     }
     
     target->image = src;
+    iso_image_ref(src);
+    
     target->iso_level = opts->level;
     
     target->now = time(NULL);
     
-    ret = ecma119_tree_create(target, src->root);
-    if (ret < 0) {
-        // TODO free image data
-        return ret;
-    }
-    
     /* 
      * 2. Based on those options, create needed writers: iso, joliet...
      * Each writer inits its structures and stores needed info into
@@ -51,6 +123,25 @@ int ecma119_image_new(IsoImage *src, Ecma119WriteOpts *opts,
      * current block.
      * Finally, create Writer for files.
      */
+    target->curblock = 16; 
+    
+    /* the number of writers is dependent of the extensions */
+    target->writers = malloc(2 * sizeof(void*));
+    if (target->writers == NULL) {
+        iso_image_unref(src);
+        free(target);
+        return ISO_MEM_ERROR;
+    }
+    
+    /* create writer for ECMA-119 structure */
+    ret = ecma119_writer_create(target);
+    if (ret < 0) {
+        goto target_cleanup;
+    }
+    
+    /* Volume Descriptor Set Terminator */
+    target->curblock++;
+    
     
     /*
      * 3. 
@@ -58,12 +149,24 @@ int ecma119_image_new(IsoImage *src, Ecma119WriteOpts *opts,
      * That function computes the size needed by its structures and
      * increments image current block propertly.
      */
-    
+    for (i = 0; i < target->nwriters; ++i) {
+        IsoImageWriter *writer = target->writers[i];
+        ret = writer->compute_data_blocks(writer);
+        if (ret < 0) {
+            goto target_cleanup;
+        }
+    }
     
     /* 4. Start writting thread */ 
     
+    
+    
     *img = target;
     return ISO_SUCCESS;
+    
+target_cleanup:;
+    ecma119_image_free(target);
+    return ret;
 }
 
 static int
@@ -83,12 +186,7 @@ bs_get_size(struct burn_source *bs)
 static void
 bs_free_data(struct burn_source *bs)
 {
-    Ecma119Image *t = (Ecma119Image*)bs->data;
-    ecma119_node_free(t->root);
-    iso_image_unref(t->image);
-    iso_file_src_free(t);
-    
-    free(t);
+    ecma119_image_free((Ecma119Image*)bs->data);
 }
 
 static
diff --git a/src/ecma119.h b/src/ecma119.h
index 9ab79de..76c8ccb 100644
--- a/src/ecma119.h
+++ b/src/ecma119.h
@@ -11,6 +11,8 @@
 
 #include "libisofs.h"
 
+#include <stdint.h>
+
 typedef struct ecma119_image Ecma119Image;
 typedef struct ecma119_node Ecma119Node;
 typedef struct Iso_File_Src IsoFileSrc;
@@ -20,8 +22,6 @@ struct ecma119_image {
     IsoImage *image;
     Ecma119Node *root;
     
-    //int volnum;
-    
     unsigned int iso_level:2;
     
 //    int relaxed_constraints; /**< see ecma119_relaxed_constraints_flag */
@@ -47,6 +47,15 @@ struct ecma119_image {
                         *  includes the current volume. */
     //uint32_t vol_space_size;
 
+    /*
+     * Block being processed, either during image writing or structure
+     * size calculation.
+     */
+    uint32_t curblock;
+    
+    size_t nwriters;
+    IsoImageWriter **writers;
+
     /* tree of files sources */
     void *file_srcs;
     int file_count;
diff --git a/src/ecma119_tree.c b/src/ecma119_tree.c
index 1f77829..15d5923 100644
--- a/src/ecma119_tree.c
+++ b/src/ecma119_tree.c
@@ -13,6 +13,7 @@
 #include "util.h"
 #include "filesrc.h"
 #include "messages.h"
+#include "image.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -132,6 +133,9 @@ int create_file(Ecma119Image *img, IsoFile *iso, Ecma119Node **node)
 
 void ecma119_node_free(Ecma119Node *node)
 {
+    if (node == NULL) {
+        return;
+    }
     if (node->type == ECMA119_DIR) {
         int i;
         for (i = 0; i < node->info.dir.nchildren; i++) {
@@ -492,12 +496,12 @@ int mangle_tree(Ecma119Image *img)
 }
 
 
-int ecma119_tree_create(Ecma119Image *img, IsoDir *iso)
+int ecma119_tree_create(Ecma119Image *img)
 {
     int ret;
     Ecma119Node *root;
     
-    ret = create_tree(img, (IsoNode*)iso, &root, 1, 0);
+    ret = create_tree(img, (IsoNode*)img->image->root, &root, 1, 0);
     if (ret < 0) {
         return ret;
     }
diff --git a/src/ecma119_tree.h b/src/ecma119_tree.h
index 31866f8..f0c4547 100644
--- a/src/ecma119_tree.h
+++ b/src/ecma119_tree.h
@@ -55,7 +55,7 @@ struct ecma119_node
 /**
  * 
  */
-int ecma119_tree_create(Ecma119Image *img, IsoDir *iso);
+int ecma119_tree_create(Ecma119Image *img);
 
 /**
  * Free an Ecma119Node, and its children if node is a dir
diff --git a/src/filesrc.c b/src/filesrc.c
index 39f3d9e..575eee8 100644
--- a/src/filesrc.c
+++ b/src/filesrc.c
@@ -115,5 +115,7 @@ void free_node(void *nodep)
 
 void iso_file_src_free(Ecma119Image *img)
 {
-    tdestroy(img->file_srcs, free_node);
+    if (img->file_srcs != NULL) {
+        tdestroy(img->file_srcs, free_node);
+    }
 }
diff --git a/src/writer.h b/src/writer.h
index 5749fe6..af61471 100644
--- a/src/writer.h
+++ b/src/writer.h
@@ -17,15 +17,16 @@ struct Iso_Image_Writer
      */
     int (*compute_data_blocks)(IsoImageWriter *writer);
     
-    int (*write_vol_desc)(IsoImageWriter *writer, int fd);
+    int (*write_vol_desc)(IsoImageWriter *writer);
     
-    int (*write_data)(IsoImageWriter *writer, int fd);
+    int (*write_data)(IsoImageWriter *writer);
     
     int (*free_data)(IsoImageWriter *writer);
     
     void *data;
-    Ecma119Image *image;
-    IsoImageWriter *next;
+    Ecma119Image *target;
 };
 
+int ecma119_writer_create(Ecma119Image *target);
+
 #endif /*LIBISO_IMAGE_WRITER_H_*/