. By Alessandro Rubini & Jonathan Corbet . 2nd Edition June 2001 . 0-59600-008-1, Order Number: 0081 . 586 pages, $39.95 . ioctl . Blocking I/O . poll and select . Asynchronous Notification . Seeking a Device . Access Control on a Device File . Backward Compatibility . Quick Reference . In Chapter 3, "Char Drivers", we built a complete device driver that the user can write to and read from. But a real device usually offers more functionality than synchronous read and write . Now that we're equipped with