Hi list, I'm a newbie, and I just read about the mmap system call. I have a very basic confusion regarding why would a driver ever want to implement mmap. 1) The purpose of mmap is to map the device memory to user space programs, right? Isn't that alreay available via /dev/mem? The interested userspace programs can directly mmap (the required offset in) /dev/mem into their address space, and the task is done? No? 2) Is it that mmapping /dev/mem works only for memory (RAM)? Are all physical addresses not available via /dev/mem? Thanks, Dan - To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.linux-learn.org/faqs