Resolving Alternate Paths to Facilities in Systems With Dynamic Configurability
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Feb-01
This article describes a technique for use in I/O subsystems of data processing systems which resolves alternate paths to I/O facilities, thereby eliminating ambiguity as to facilities actually shared. In a system supporting dynamic configurability where alternate paths to a given facility exist, the system configuration control program will receive multiple requests for attachment from facilities to which there are alternate paths. Since each request will have a different address for the facility, a mechanism is needed to recognize that it is exactly the same facility to preclude multiple programs connecting to the facility and to determine that alternate paths do exist to the facility in case of breakage in one of the paths.