INT 15H 91H: Interrupt Finished

 Expects: AH    91H
          AL    device type:  00H fixed disk time-out
                              01H diskette time-out
                              02H keyboard
                              03H pointed device time-out
                              21H waiting foe keyboard input
                              80H network
                              fcH fixed-disk reset time-out
                              fdH diskette drive motor start
                              feH pointing device time-out
          ES:BX addr of network control block (if AL = 80H or higher)
          CF    must be NC (0) before calling
 Returns: (none)
    Info: This service is designed to be intercepted by a multitasking
          operating system.  It could be used by disk or other hardware
          handlers so the handler can be notified when I/O is completed.
          This fn could also be used by an operating system to learn when
          I/O is completed so the requesting task could be reactivated.

          When unintercepted, the BIOS simply sets AH to 0 and clears CF.

See Also: INT 15H (extended AT services)
          BIOS Data Area
          ROM-BIOS Functions