Hi , I wanted to know where the functions "inb","outb" , ...etc . I checked out the below file : /usr/src/linux/include/asm-i386/io.h which has comment saying definitions are in that file , but I could not understand it . Kindly please help me understand how this works . Thanks in advance . Regards ! ________________________________________________________________________ Missed your favourite TV serial last night? Try the new, Yahoo! TV. visit http://in.tv.yahoo.com -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/