Hi... just dwelling into writing a device driver and yes have got some of it sorted out.. however I would like to know where the prototype for memcpy_tofs recides. I'm using 2.4.18 Kernel and don't seem to fine\d it anywhere.. I have found the #defines which define copy_to_user(...) as memcpy_tofs but when I include the libraries, I get problems with the tagged initialization of the read funtion in file_operations. thanks in advance sharath __________________________________________________ Do You Yahoo!? Yahoo! Tax Center - online filing with TurboTax http://taxes.yahoo.com/ -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/