Two quick questions: I got "implicit declaration of function `module_register_chrdev'" during the compilation with kernel 2.4.2 on Pentium 4. I wonder the module_register_chrdev() should be replaced by inter_module_register()? Secondly, the device_read and device_write in my following code warning me: initialization from incompatible pointer type It seems to me that file_operations defined in linux/include/fs.h is changed. Could someone tell how it is changed and how can I trace the change? struct file_operations Fops = { NULL, /* seek */ device_read, device_write, NULL, /* readdir */ NULL, /* select */ NULL, /* ioctl */ NULL, /* mmap */ device_open, NULL, /* flush */ device_release /* a.k.a. close */ }; Thanks, -Hong - Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ IRC Channel: irc.openprojects.net / #kernelnewbies Web Page: http://www.kernelnewbies.org/