On Tue, Jul 5, 2011 at 12:29 PM, Paraneetharan Chandrasekaran <[email protected]> wrote: > I think the thread originator is asking about how the application knows > which device file to read or write. > This is done by h/w management system udev. udev creates/manages device > nodes in /dev/ dir and notifes applications based on the udev rules written > (via HAL events or DBUS signals).
I don't think udev is involved in the read/write file ops. Udev is responsible for handling hotplug events, doing certain actions based on events (as indicated by udev rules),persistent naming of devices etc...but not file i/o. That, I think, is handled by the VFS layer. Each device node is uniquely identified by it's MAJOR-MINOR number combo. I guess the VFS layer uses this to pick the correct file-ops struct to communicate with the device. So when we try to open a device, say /devtyyS0, it's major-minor numbers My info is a little dated, so plz CMIIW. HTH, -mandeep _______________________________________________ Kernelnewbies mailing list [email protected] http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
