diff --git a/src/obiarray.c b/src/obiarray.c
index fd4015d..220277f 100644
--- a/src/obiarray.c
+++ b/src/obiarray.c
@@ -787,8 +787,16 @@ OBIDMS_array_p obi_open_array(OBIDMS_p dms, const char* array_name)
 		return NULL;
 	}
 
+	// Read the header size
+	if (read(array_data_file_descriptor, &header_size, sizeof(size_t)) < sizeof(size_t))
+	{
+		obi_set_errno(OBI_ARRAY_ERROR);
+		obidebug(1, "\nError reading the header size to open a data array");
+		close(array_data_file_descriptor);
+		return NULL;
+	}
+
 		// Fill the array data structure
-	header_size = get_array_data_header_size();	// TODO should be read?
 	array_data->header = mmap(NULL,
 			                  header_size,
 			                  PROT_READ | PROT_WRITE,
@@ -858,8 +866,16 @@ OBIDMS_array_p obi_open_array(OBIDMS_p dms, const char* array_name)
 		return NULL;
 	}
 
+		// Read the header size
+	if (read(array_file_descriptor, &header_size, sizeof(size_t)) < sizeof(size_t))
+	{
+		obi_set_errno(OBI_ARRAY_ERROR);
+		obidebug(1, "\nError reading the header size to open an array");
+		close(array_file_descriptor);
+		return NULL;
+	}
+
 		// Fill the array structure
-	header_size = get_array_header_size();	// TODO should be read?
 	array->header = mmap(NULL,
 			             header_size,
 			             PROT_READ | PROT_WRITE,
@@ -911,13 +927,6 @@ int obi_close_array(OBIDMS_array_p array)	// TODO when do we call it? (as multip
 
 	ret_val = close_array_data(array->data);
 
-	if (munmap(array->header, (array->header)->header_size) < 0)
-	{
-		obi_set_errno(OBI_ARRAY_ERROR);
-		obidebug(1, "\nError munmapping the header of an array file");
-		ret_val = -1;
-	}
-
 	if (munmap(array->first, (((array->header)->nb_items_max) * sizeof(index_t))) < 0)
 	{
 		obi_set_errno(OBI_ARRAY_ERROR);
@@ -925,6 +934,13 @@ int obi_close_array(OBIDMS_array_p array)	// TODO when do we call it? (as multip
 		ret_val = -1;
 	}
 
+	if (munmap(array->header, (array->header)->header_size) < 0)
+	{
+		obi_set_errno(OBI_ARRAY_ERROR);
+		obidebug(1, "\nError munmapping the header of an array file");
+		ret_val = -1;
+	}
+
 	free(array);
 
 	return ret_val;
diff --git a/src/obidmscolumn.c b/src/obidmscolumn.c
index e4f7055..4ae2d4d 100644
--- a/src/obidmscolumn.c
+++ b/src/obidmscolumn.c
@@ -191,11 +191,10 @@ static obiversion_t obi_get_new_version_number(OBIDMS_column_directory_p column_
 	obiversion_t 	new_version_number;
 	char* 			version_file_name;
 	int    			version_file_descriptor;
-	bool   			little_endian;
 	int 			lock_mode;
 
 	new_version_number = 0;
-	loc_size = sizeof(bool) + sizeof(obiversion_t);
+	loc_size = sizeof(obiversion_t);
 
 	// Select the correct lockf operation according to the blocking mode
 	if (block)
@@ -252,24 +251,6 @@ static obiversion_t obi_get_new_version_number(OBIDMS_column_directory_p column_
 		return -1;
 	}
 
-	// Read the endianness of the file
-    if (read(version_file_descriptor, &little_endian, sizeof(bool)) < sizeof(bool))
-	{
-		obi_set_errno(OBICOL_UNKNOWN_ERROR);
-		obidebug(1, "\nError reading the endianness of a version file");
-		close(version_file_descriptor);
-		return -1;
-	}
-
-    // Check if endianness is correct
-    if (little_endian != obi_is_little_endian())
-	{
-		obi_set_errno(OBICOL_BAD_ENDIAN_ERROR);
-		obidebug(1, "\nEndianness of a version file is incorrect");
-		close(version_file_descriptor);
-		return -1;
-	}
-
     // Read the current version number
     if (read(version_file_descriptor, &new_version_number, sizeof(obiversion_t)) < sizeof(obiversion_t))
 	{
@@ -282,14 +263,6 @@ static obiversion_t obi_get_new_version_number(OBIDMS_column_directory_p column_
     new_version_number++;
 
     // Write the new version number
-	if (lseek(version_file_descriptor, sizeof(bool), SEEK_SET) != sizeof(bool))
-	{
-		obi_set_errno(OBICOL_UNKNOWN_ERROR);
-		obidebug(1, "\nError writing a new version number in a version file");
-		close(version_file_descriptor);
-		return -1;
-	}
-
 	if (write(version_file_descriptor, &new_version_number, sizeof(obiversion_t)) < sizeof(obiversion_t))
 	{
 		obi_set_errno(OBICOL_UNKNOWN_ERROR);
@@ -328,9 +301,8 @@ static obiversion_t create_version_file(OBIDMS_column_directory_p column_directo
 	obiversion_t 	version_number;
 	char* 			version_file_name;
 	int    			version_file_descriptor;
-	bool   			little_endian;
 
-	loc_size = sizeof(bool) + sizeof(obiversion_t);
+	loc_size = sizeof(obiversion_t);
 	version_number = 0;
 
 	version_file_name = build_version_file_name(column_directory->column_name);
@@ -376,17 +348,6 @@ static obiversion_t create_version_file(OBIDMS_column_directory_p column_directo
 		return -1;
 	}
 
-	little_endian = obi_is_little_endian();
-
-	// Write endianness
-	if (write(version_file_descriptor, &little_endian, sizeof(bool)) < sizeof(bool))
-	{
-		obi_set_errno(OBICOL_UNKNOWN_ERROR);
-		obidebug(1, "\nError writing endianness of a version file");
-		close(version_file_descriptor);
-		return -1;
-	}
-
 	// Write version number
 	if (write(version_file_descriptor, &version_number, sizeof(obiversion_t)) < sizeof(obiversion_t))
 	{
@@ -444,9 +405,8 @@ obiversion_t obi_get_latest_version_number(OBIDMS_column_directory_p column_dire
 	obiversion_t 	latest_version_number;
 	char * 			version_file_name;
 	int    			version_file_descriptor;
-	bool   			little_endian;
 
-	loc_size = sizeof(bool) + sizeof(obiversion_t);
+	loc_size = sizeof(obiversion_t);
 	latest_version_number = 0;
 
 	version_file_name = build_version_file_name(column_directory->column_name);
@@ -483,24 +443,6 @@ obiversion_t obi_get_latest_version_number(OBIDMS_column_directory_p column_dire
 		return -1;
 	}
 
-	// Read the endianness
-    if (read(version_file_descriptor, &little_endian, sizeof(bool)) < sizeof(bool))
-	{
-		obi_set_errno(OBICOL_UNKNOWN_ERROR);
-		obidebug(1, "\nError reading the endianness of a version file");
-		close(version_file_descriptor);
-		return -1;
-	}
-
-    // Verify the endianness
-    if (little_endian != obi_is_little_endian())
-	{
-		obi_set_errno(OBICOL_BAD_ENDIAN_ERROR);
-		obidebug(1, "\nEndianness of a version file is incorrect");
-		close(version_file_descriptor);
-		return -1;
-	}
-
     // Read the latest version number
     if (read(version_file_descriptor, &latest_version_number, sizeof(obiversion_t)) < sizeof(obiversion_t))
 	{
@@ -731,7 +673,6 @@ OBIDMS_column_p obi_create_column(OBIDMS_p    dms,
 	new_column->writable  = true;
 
 	header 				  		 = new_column->header;
-	header->little_endian 		 = obi_is_little_endian();
 	header->header_size   		 = header_size;
 	header->data_size			 = data_size;
 	header->line_count   	 	 = nb_lines;
@@ -793,9 +734,6 @@ OBIDMS_column_p obi_open_column(OBIDMS_p dms,
 		return NULL;
 	}
 
-	// Calculate the header size
-	header_size = obi_get_platform_header_size();
-
 	// Get the latest version number if it has the value -1 (not given by user)
 	if (version_number == -1)
 	{
@@ -836,6 +774,16 @@ OBIDMS_column_p obi_open_column(OBIDMS_p dms,
 		return NULL;
 	}
 
+	// Read the header size
+	if (read(column_file_descriptor, &header_size, sizeof(size_t)) < sizeof(size_t))
+	{
+		obi_set_errno(OBICOL_UNKNOWN_ERROR);
+		obidebug(1, "\nError reading the header size to open a column");
+		close(column_file_descriptor);
+		free(column);
+		return NULL;
+	}
+
 	// Fill the column structure
 	column->dms    			 = dms;
 	column->column_directory = column_directory;
@@ -1265,9 +1213,6 @@ OBIDMS_column_header_p obi_column_get_header_from_name(OBIDMS_p dms, const char*
 		return NULL;
 	}
 
-	// Calculate the header size
-	header_size = obi_get_platform_header_size();	// TODO read in header itself
-
 	// Get the latest version number
 	version_number = obi_get_latest_version_number(column_directory);
 	if (version_number < 0)
@@ -1295,6 +1240,15 @@ OBIDMS_column_header_p obi_column_get_header_from_name(OBIDMS_p dms, const char*
 
 	free(column_file_name);
 
+	// Read the header size
+	if (read(column_file_descriptor, &header_size, sizeof(size_t)) < sizeof(size_t))
+	{
+		obi_set_errno(OBICOL_UNKNOWN_ERROR);
+		obidebug(1, "\nError reading the header size to read a header");
+		close(column_file_descriptor);
+		return NULL;
+	}
+
 	// Fill the header structure
 	header = mmap(NULL,
 			 header_size,
diff --git a/src/obidmscolumn.h b/src/obidmscolumn.h
index 399a171..bcf76bb 100644
--- a/src/obidmscolumn.h
+++ b/src/obidmscolumn.h
@@ -48,11 +48,6 @@ typedef int32_t obiversion_t; 	/**< Used to store the column version number
  * @brief OBIDMS column header structure.
  */
 typedef struct OBIDMS_column_header {
-	bool			little_endian;		        			/**< Endianness of the column:
-											     	 	 	 *   	- `true`  on little endian platforms
-											     	 	 	 *		- `false` on big endian platforms
-											     	 	 	 *   @see obi_is_little_endian()
-											     	 	 	 */
 	size_t			header_size;		   				    /**< Size of the header in bytes.
 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 */
 	size_t			data_size;			   				    /**< Size of the data in bytes.
diff --git a/src/obierrno.h b/src/obierrno.h
index 568c75f..5a0c478 100644
--- a/src/obierrno.h
+++ b/src/obierrno.h
@@ -65,25 +65,25 @@ extern int obi_errno;
                                     		 */
 #define OBIDMS_ACCESS_ERROR    		(6) 	/**< Permission error trying to access the database
                                     		 */
-
-#define OBICOLDIR_EXIST_ERROR     	(7) 	/**< Trying to create an OBIDMS column directory with a name
-                                    		 *   that corresponds to an existing one
-                                    		 */
-#define OBICOLDIR_NOT_EXIST_ERROR 	(8) 	/**< Trying to open a non-existing OBIDMS column directory
-                                    		 */
-#define OBICOLDIR_LONG_NAME_ERROR 	(9) 	/**< The specified OBIDMS column directory name is too long
-                                    		 */
-#define OBICOLDIR_MEMORY_ERROR    	(10) 	/**< A memory error occurred during allocation while handling
-											 *	 an OBIDMS column directory
-                                    	 	 */
-#define OBICOLDIR_UNKNOWN_ERROR   	(11) 	/**< Undetermined error while handling an OBIDMS column directory
-                                    	 	 */
-#define OBICOLDIR_ACCESS_ERROR    	(12) 	/**< Permission error trying to access an OBIDSM column directory
-                                    		 */
-
-#define OBICOL_BAD_ENDIAN_ERROR   	(13) 	/**< The opened data structure does not corresponds
+#define OBIDMS_BAD_ENDIAN_ERROR   	(7) 	/**< The opened database does not correspond
                                     		 *   to the endianness of the platform.
                                     		 */
+
+#define OBICOLDIR_EXIST_ERROR     	(8) 	/**< Trying to create an OBIDMS column directory with a name
+                                    		 *   that corresponds to an existing one
+                                    		 */
+#define OBICOLDIR_NOT_EXIST_ERROR 	(9) 	/**< Trying to open a non-existing OBIDMS column directory
+                                    		 */
+#define OBICOLDIR_LONG_NAME_ERROR 	(10) 	/**< The specified OBIDMS column directory name is too long
+                                    		 */
+#define OBICOLDIR_MEMORY_ERROR    	(11) 	/**< A memory error occurred during allocation while handling
+											 *	 an OBIDMS column directory
+                                    	 	 */
+#define OBICOLDIR_UNKNOWN_ERROR   	(12) 	/**< Undetermined error while handling an OBIDMS column directory
+                                    	 	 */
+#define OBICOLDIR_ACCESS_ERROR    	(13) 	/**< Permission error trying to access an OBIDSM column directory
+                                    		 */
+
 #define OBICOL_EXIST_ERROR     		(14) 	/**< Trying to create an OBIDMS column with a name
                                     		 *   that corresponds to an existing one
                                     		 */