Abstract: A computer program product is configured for performing a method including: receiving at least one command message specifying an I/O operation at a control unit from a channel subsystem, the at least one command message including one or more device command words (DCWs) having a data count and a suppress-length indication (SLI), the SLI configured to instruct the control unit whether to continue to perform the I/O operation in response to the control unit detecting an incorrect length condition; processing at least one of the one or more DCWs; and returning a transport response message including an incorrect length (IL) value, the IL value being a first IL value in response to the SLI being a first SLI value and the data count not matching the amount of data required, the IL value being a second IL value in response to the SLI being a second SLI value and the data count not matching the amount of data required.

Abstract: A computer program product is configured for performing a method including: receiving at least one command message specifying an I/O operation at a control unit from a channel subsystem, the at least one command message including one or more device command words (DCWs) having a data count and a suppress-length indication (SLI), the SLI configured to instruct the control unit whether to continue to perform the I/O operation in response to the control unit detecting an incorrect length condition; processing at least one of the one or more DCWs; and returning a transport response message including an incorrect length (IL) value, the IL value being a first IL value in response to the SLI being a first SLI value and the data count not matching the amount of data required, the IL value being a second IL value in response to the SLI being a second SLI value and the data count not matching the amount of data required.

Abstract: A computer program product is provided for performing: sending, by a channel subsystem, a process login (PRLI) request message to the control unit that indicates whether the channel subsystem supports bi-directional data transfer; receiving a PRLI response message from the control unit that indicates whether the control unit supports bi-directional data transfer; gathering a plurality of commands, at least one which specifies an input data transfer and at least one specifying an output data transfer; sending at least one output data message to the control unit including output data to be transferred to the control unit, the output data message associated with the at least one of the plurality of commands specifying an output data transfer; and receiving at least one input message from the control unit including input data to be stored in a main storage of the host computer system.

Abstract: A network system supports multiple network communication protocols. In one embodiment, network device driver software provides a “Fiber Channel over Ethernet” communication capability and methodology. Device driver software manages a Fiber Channel to Ethernet and Ethernet to Fiber Channel address translation in real time for data packet communications in the network system. Different embodiments of the disclosed network system include multiple name servers and network device driver software that together provide multiple adapter name discovery methodologies. In one embodiment, the adapter name discovery methodologies include port name discovery and adapter attributes discovery.

Abstract: A network system supports multiple network communication protocols. An Ethernet component gateway in a Fiber Channel over Ethernet (FCoE) initiator system converts FCoE data packets from host devices to Fiber Channel over Internet Protocol (FCIP) data packets for transmission to a Storage Area Network (SAN) target system. The SAN target system may include a target Fiber Channel (FC) storage device and a SAN component gateway. The SAN component gateway converts FCIP data packets to SAN data packets for use by the target FC storage device. The SAN data packets may be either FC protocol data packets or FCoE protocol data packets. The SAN target system may provide for discovery of target FC storage device adapter information.

Abstract: A method of processing communications includes: receiving transmission data over a selected time interval for each of a plurality of communication paths between a host processor and a control unit configured to control at least one I/O device; calculating an average round-trip transmission time for each of the communication paths over the time interval; comparing an average round-trip transmission time for a communication path having the highest average round-trip transmission time to a threshold value and to a multiple of an average round-trip transmission time for a communication path having the lowest average round-trip transmission time; and determining, based on comparing the highest round-trip transmission time to the threshold value and to a multiple of the lowest round-trip transmission time, whether the time period indicates a delay in communication between the I/O subsystem and the control unit requiring at least one of a monitoring action and a recovery action.

Abstract: A Fiber Channel over Ethernet (FCoE) device obtains knowledge of the configuration of an attached Ethernet fabric from data fields within a frame header during a fabric initialization or login (FLOGI) process. FCoE N_Ports obtain similar information during the port initialization or login (PLOGI) process. The FCoE device may provide network management services to attached FCoE devices. Embodiments include a management module or processor within an FCoE N_Port. The management module or processor receives a frame having a header and validates and extracts information associated with an Ethernet fabric from the FCoE N_Ports and in order to provide management services based on the information associated with the Ethernet fabric. The FCoE N_Port communicatively couples to at least one additional FCoE N_Port through the Ethernet fabric. The FCoE N_Ports may be implemented within a disc storage drive, a host bus adapter, and/or an FCoE switch.

Abstract: A computer program product, an apparatus, and a method for processing communications between a target and an initiator an input/output processing system are provided. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes: sending a message from the initiator to the target, the message requesting suspension of input/output operations between the initiator and the target for a period of time, the period of time being defined by the message; responsive to the message, suspending input/output operation messages for the period of time; performing a system change comprising at least one of: at least one update, a computer program installation, a recovery, and a change in operating parameters; and initiating new input/output operations after at least one of: expiration of the period of time and initiation of new input/output operations by the initiator.

Abstract: An Extended Input/output (I/O) measurement word facility is provided. Provision is made for emulation of the Extended I/O measurement word facility. The facility provides for storing measurement data associated with a single I/O operation in an extended measurement word associated with an I/O response block. In a further aspect, the stored data may have a resolution of approximately one-half microsecond.

Abstract: A computer program product, an apparatus, and a method for processing communications between a control unit and a channel subsystem in an input/output processing system are provided. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method including: sending a message from the channel subsystem to the control unit in a first mode; receiving a response from the control unit and determining from the response whether the control unit supports a message protocol; and responsive to the message protocol being supported by the control unit, sending another message using the message protocol from the channel subsystem to the control unit to determine whether the control unit supports a second mode.

Abstract: A computer program product, apparatus, and method for handling early termination of an I/O operation at a channel subsystem in an I/O processing system are provided. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes receiving a request to terminate an I/O operation, and transmitting an abort command to a control unit in communication with the channel subsystem in response to receiving the request to terminate the I/O operation. The method also includes transmitting a purge path command to purge a path associated with the I/O operation, where the purge path command includes an error code identifying the request to terminate the I/O operation.

Abstract: The state of an input/output (I/O) operation is determined in an I/O processing system. A command is received from an I/O operating system at a channel subsystem for initiating the I/O operation, a time period is for completion of the I/O operation, and the command for initiating the I/O operation is sent from the channel subsystem to the control unit. Responsive to the time period nearing elapsing without the I/O operation completing, a cancel instruction is received from the I/O operating system at the channel subsystem. Responsive to a determination by the I/O operating system to interrogate the control unit, an instruction to interrogate the control unit is received with the cancel instruction from the I/O operating system.

Abstract: An Extended Input/output (I/O) measurement word facility is provided. Provision is made for emulation of the Extended I/O measurement word facility. The facility provides for storing measurement data associated with a single I/O operation in an extended measurement word associated with an I/O response block. In a further aspect, the stored data may have a resolution of approximately one-half microsecond.

Abstract: A state of an input/output (I/O) operation in an I/O processing system is determined. A request for performing the I/O operation is received from an I/O operating system at a channel subsystem and forwarded to a control unit controlling an I/O device for executing the I/O operation. After a predetermined amount of time passes without receiving indication from the control unit that the I/O operation is completed, an interrogation request is received at the channel subsystem from the I/O operating system for determining the state of the I/O operation. An interrogation command is sent from the channel subsystem to the control unit. A response is received from the control unit, the response indicates a state of the I/O device executing the I/O operation, a state of the control unit controlling the I/O device executing the I/O operation, and the state of the I/O operation being executed.

Abstract: A computer program product is provided for performing a method including: receiving transmission data over a selected time interval for each of a plurality of communication paths; calculating an average round-trip transmission time for each of the plurality of communication paths over the time interval; comparing an average round-trip transmission time for a communication path having the highest average round-trip transmission time to a threshold value and to a multiple of an average round-trip transmission time for a communication path having the lowest average round-trip transmission time; and determining, based on a result of comparing the highest round-trip transmission time to the threshold value and to a multiple of the lowest round-trip transmission time, whether the time period indicates a delay in communication between the I/O subsystem and the control unit requiring at least one of a monitoring action and a recovery action.

Abstract: A computer program product, apparatus, and method for handling exception condition feedback at a channel subsystem of an I/O processing system using data from a control unit are provided. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes sending a command message to the control unit, and receiving a response message in response to the command message. The response message includes exception condition feedback identifying a termination reason code in response to unsuccessful execution of at least one command in the command message. The method also includes interrupting a CPU in the I/O processing system, and reporting status associated with the exception condition feedback to the CPU in an interrupt response block.

Abstract: A method for detecting virtual images in a network, the network including a host system and a plurality of physical devices in operable communication with one another, includes forming a query packet at the host system; providing the query packet to at least one of the plurality of physical devices; forming at the at least of the plurality of physical devices a first vector in response to the query packet, the first vector including a bit for each possible virtual image that may be formed in the at least one of the plurality of devices and indicating which of the virtual images are configured and addressable; and providing the first vector to the host system.

Abstract: Server time protocol (STP) messages and methods of exchange thereof are provided for facilitating synchronization of processing units of a timing network. The STP messages include exchange time parameters (XTP) commands and responses, and STP control (STC) commands and responses. XTP message exchange processing includes: generating an XTP message command at a first processing unit including a command transmit timestamp field set by the first processing unit and a command receive timestamp field which is unset by the first processing unit; transmitting the XTP message command to a second processing unit; setting the command receive timestamp field in the XTP command with the time the XTP command is received at the second processing unit; and generating an XTP message response at the second processing unit, the message response including the command transmit timestamp set by the first processing unit and the command receive timestamp set by the second processing unit.

Abstract: A server of a network of servers determines that its power source is failing. In response, the server communicates to one or more other servers of this network that it is leaving the network. This communication is powered by another power source.

Abstract: A method for detecting a switch failure and managing switch failover in a Fiber Channel over Ethernet network. The plurality of Fiber Channel over Ethernet switches are connected to an intermediary Ethernet switch and to each other via an Ethernet connection. The intermediary Ethernet switch is different from the plurality of Fiber Channel over Ethernet switches. A plurality of end ports are also connected to the intermediary Ethernet switch. A failure is detected in a first switch in the plurality of Fiber Channel over Ethernet switches. The first switch is associated with a first end port in the plurality of end ports. A failure notification is sent to the first end port using the intermediary Ethernet switch. The failure notification might specify a second switch destination and an identification of the first switch. A fabric login is exchanged between the first end port and the second switch.