Patent ID: 8006133
Filing Date: 2011-08-23
Classification: G06F

Abstract:
1. A method for fault tolerant operation and diagnosis of an I/O (Input/Output) adapter, said method comprising: assigning a primary I/O adapter and a redundant I/O adapter of a data processing system to support access to a system resource; while the primary I/O adapter is in service and the redundant I/O adapter is not in service in providing access to the system resource, issuing a fail over command to remove the primary I/O adapter from service and place the redundant I/O adapter in service in supporting access to the system resource, wherein the issuing includes issuing the fail over command in response to detection of a potential fault with the primary I/O adapter; in response to the fail over command, reading a state of the primary I/O adapter, transferring the state of the primary I/O adapter to the redundant I/O adapter, and enabling the redundant I/O adapter to assume support for access to the system resource; while the redundant I/O adapter is in service and the primary I/O adapter is not in service in providing access to the system resource, performing diagnostic testing on the primary I/O adapter; in response to the diagnostic testing revealing no fault in the primary I/O adapter, issuing a fail back command to restore the primary I/O adapter to service and remove the redundant I/O adapter from service in supporting access to the system resource; in response to the fail back command, reading a state of the redundant I/O adapter, transferring the state of the redundant I/O adapter to the primary I/O adapter, and enabling the primary I/O adapter to assume support for access to the system resource; and in response to the diagnostic testing revealing a fault in the primary I/O adapter, transmitting a message indicating presence of a fault in the primary I/O adapter and retaining the redundant I/O adapter in service to support access to the system resource.