Device-special File

Device-special File

Once you write a kernel-level IRIX device driver, communication with a device is a matter of accessing a file called a device-special file. Each device has its own device-special file, conventionally kept in the /dev directory. Because IRIX makes kernel-driven devices look like files, a user-level process can use the standard operating system calls to open the file/device, read from the file/device, write to the file/device, and so on. For most I/O operations, the user program needs no device-specific system call when it deals with a device driven by a kernel-level device driver. See the ioctl(D2) man page.

Creating Device-special Files
Major and Minor Device Numbers
Device-special File Example