Hi http://hpux-tips.blogspot.com/ pay attention to 13. mknod /dev/async c 101 0x000000 Yes this file was necessary last time i used HP-UX 14. chown oracle:dba /dev/async (the special are created with crw-rw-rw- so you don't need perform that... it's your choice...) 15. chmod 660 /dev/async You can do tusc on dbwr to see that async io is being used something like open("/dev/async" regards Hrishy -- //www.freelists.org/webpage/oracle-l