diff --git a/src/options.h b/src/options.h
index dcf39f9..7b84ad9 100644
--- a/src/options.h
+++ b/src/options.h
@@ -38,6 +38,7 @@
 #define MAX_DRIVE_PATH_LENGTH 200  // e.g. /dev/sda is only 8 characters long, so 200 should be plenty.
 #define DEFAULT_SYNC_RATE 100000
 #define PATHNAME_MAX 2048
+#define NWIPE_USE_DIRECT_IO
 
 /* Function prototypes for loading options from the environment and command line. */
 int nwipe_options_parse( int argc, char** argv );