Dear Giles, Please find the attached file of used code . Iam sure that iam not leaving primary mode but iam using rt_printf(" xenomai") in a for loop to print for some 1000 times. Ok if i leave primary mode i might get some delay than expected but what happens if we use rt_printf to print 1000 times . And please let me know how run some background process with this program on pandaboard with only minicom login. Thanks