Hello, A while ago I read Rubbini's Device driver book. I couldn't complile the simple "Hello World" module due to "Version Mismatch". Using "insmod -f" worked but then "rmmod" couldn't unload the module" and rebooting was required. So, I just went ahead and compiled the pseudo driver into the kernel instead of as a module. I would still like to be able to be able to write a driver as a module in Linux and avoid the long compile reboot cycle. Can someone give me poitners how to get over the version mismatch ? My kernel version is 2.4.20 (Red Hat 8.0) and far as I remember , module.h wants "2.4.9" or something. The following attempts did not succeed: 1. Make menuconfig.............. Set version information on modules = "NO" In this case the OS wouldn't boot properly. It could mount the filesystem saying "optional symbols" could not be found. 2. Instead of #include <linux/module.h>, I tried # include "/home/tony/mykernel/include/linux/module.h" There is no difference in results in this case. Thanks, Tony -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/