diff --git a/src/ecma119.c b/src/ecma119.c
index 60c7dbf..ee05ada 100644
--- a/src/ecma119.c
+++ b/src/ecma119.c
@@ -20,6 +20,7 @@
 #include <stdlib.h>
 #include <time.h>
 #include <string.h>
+#include <unistd.h>
 
 static
 void ecma119_image_free(Ecma119Image *t)
@@ -329,4 +330,15 @@ int iso_image_create(IsoImage *image, Ecma119WriteOpts *opts,
     return ISO_SUCCESS;
 }
 
-
+int iso_write(Ecma119Image *target, void *buf, size_t count)
+{
+    ssize_t result;
+    
+    result = write(target->wrfd, buf, count);
+    if (result != count) {
+        /* treat this as an error? */
+        return ISO_WRITE_ERROR;
+    } else {
+        return ISO_SUCCESS;
+    }
+}
diff --git a/src/ecma119.h b/src/ecma119.h
index 3a4571b..0288e20 100644
--- a/src/ecma119.h
+++ b/src/ecma119.h
@@ -71,6 +71,10 @@ struct ecma119_image {
     /* tree of files sources */
     void *file_srcs;
     int file_count;
+    
+    /* file descriptors for read and writing image */
+    int wrfd; /* write to here */
+    int rdfd; /* read from here */
 };
 
 #endif /*LIBISO_ECMA119_H_*/
diff --git a/src/error.h b/src/error.h
index 7907346..a69e177 100644
--- a/src/error.h
+++ b/src/error.h
@@ -21,6 +21,8 @@
 #define ISO_INTERRUPTED			-5
 #define ISO_WRONG_ARG_VALUE		-6
 
+#define ISO_WRITE_ERROR         -10
+
 #define ISO_NODE_ALREADY_ADDED          -50
 #define ISO_NODE_NAME_NOT_UNIQUE        -51
 #define ISO_NODE_NOT_ADDED_TO_DIR       -52
diff --git a/src/writer.h b/src/writer.h
index af61471..0db97be 100644
--- a/src/writer.h
+++ b/src/writer.h
@@ -27,6 +27,18 @@ struct Iso_Image_Writer
     Ecma119Image *target;
 };
 
+/**
+ * This is the function all Writers shoudl call to write data to
+ * image.
+ * Currently, it is just a wrapper for write(2) Unix system call. 
+ * 
+ * It is implemented in ecma119.c
+ * 
+ * @return
+ *      1 on sucess, < 0 error
+ */
+int iso_write(Ecma119Image *target, void *buf, size_t count);
+
 int ecma119_writer_create(Ecma119Image *target);
 
 #endif /*LIBISO_IMAGE_WRITER_H_*/