Abstract: A method, computer program product, and distributed data processing system that enables host software or firmware to map PCI adapter virtual resources to PCI bus addresses that are associated with a system image is provided. Virtual addresses maintained in a protection table segment assigned to a system image are mapped to physical addresses defined in entries of an address table segment assigned to the system image. Discontiguous memory regions identified in entries of the address table segment may thus be mapped to a contiguous virtual address space.

Abstract: A method, computer program product, and distributed data processing system for directly destroying one or more virtual resources that reside within a physical adapter and that are associated with a virtual host. Specifically, the present invention is directed to a mechanism for sharing conventional Peripheral Component Interconnect (PCI) I/O adapters, PCI-X I/O adapters, PCI-Express I/O adapters, and, in general, any I/O adapter that uses a memory mapped I/O interface for host to adapter communications.

Abstract: A mechanism for handling event notifications or interrupts in a logically partitioned computing system having IO adapters that support adapter virtualization are provided. A virtual adapter associated with a physical IO adapter detects an event, identifies a logical partition associated with the event, and writes an event notification entry in a partition interrupt control block (PICB) of the logical partition memory space. The virtual adapter notifies shared control point logic on the physical IO adapter of the update to the PICB which may then write an entry to a logical partition manager interrupt control block (LPAR manager ICB) identifying the update to the PICB and the operating system associated with the PICB. The LPAR manager may then inform the operating system of the logical partition of the updates to the PICB which may then read the entries in the PICB, process them and inform appropriate application instances of the events.

Abstract: A mechanism for modifying resources in a logically partitioned data processing system is provided. A request to modify resources associated with a virtual adapter allocated on a physical adapter is invoked. The resources associated with the virtual adapter comprise a subset of the physical adapter resources. The request to modify the physical adapter is conveyed to the physical adapter. Responsive to receipt of the request by the physical adapter, the physical adapter modifies the resources allocated to the virtual adapter.

Abstract: A system for managing descriptor lists, the system including a plurality of descriptor lists, and a descriptor list manager operative to chain any of the descriptor lists by configuring at least one entry in at least a first one of the descriptor lists to indicate the location of a second one of the descriptor lists, and manage the chain of descriptor lists as a single continuous descriptor list.

Abstract: A method of offloading, from a host data processing unit (205), the generation of data corruption-detection digests for iSCSI PDUs to be transmitted as TCP segments over respective TCP connections. An iSCSI layer processing software (310) executed by the host data processing unit provides a command descriptor list (320) containing command descriptors adapted to identify portions of at least one iSCSI PDU to be transmitted, and data corruption-detection digest descriptors (CRC DESC(PDUa); CRC DESC(PDUb)), each one associated with a respective PDU data corruption-detection digest. An iSCSI processing offload engine (223) transmits the iSCSI PDU over the respective TCP connection, based on the descriptors in the command descriptor list; during the transmission, the iSCSI PDU data corruption-detection digest are calculated, and the calculated data corruption-detection digest is saved in the corresponding data corruption-detection digest descriptor in the command descriptor list.

Abstract: A method for performing Remote Direct Memory Access (RDMA), the method including creating Direct Data Placement (DDP) segments of data using a Maximum Segment Size (MSS), called the original MSS, using the DDP segments as a payload for TCP (Transport Control Protocol) segments, TCP transmitting data including the TCP segments, and if the original MSS has changed to a new MSS, temporarily halting DDP segmentation until outstanding data has been acknowledged.

Abstract: A method for controlling access to computer memory, the method including communicating work queue elements with an application layer and with a verb layer, and indicating completion of the work queue elements, wherein both the application layer and the verb layer are capable of checking if at least one of the work queue elements is completed, independently of each other.

Abstract: The disclosed invention relates to a method and system to transmit data packets through a switched network system that is composed of a plurality of routing entities. The method determines whether or not the output port assigned to the data packet and the associated input port are local to the routing entity by referencing an index pointer to a routing table.

Abstract: An RNIC implementation that performs direct data placement to memory where all segments of a particular connection are aligned, or moves data through reassembly buffers where all segments of a particular connection are non-aligned. The type of connection that cuts-through without accessing the reassembly buffers is referred to as a “Fast” connection because it is highly likely to be aligned, while the other type is referred to as a “Slow” connection. When a consumer establishes a connection, it specifies a connection type. The connection type can change from Fast to Slow and back. The invention reduces memory bandwidth, latency, error recovery using TCP retransmit and provides for a “graceful recovery” from an empty receive queue. The implementation also may conduct CRC validation for a majority of inbound DDP segments in the Fast connection before sending a TCP acknowledgement (Ack) confirming segment reception.

Abstract: An RNIC implementation that performs direct data placement to memory where all segments of a particular connection are aligned, or moves data through reassembly buffers where all segments of a particular connection are non-aligned. The type of connection that cuts-through without accessing the reassembly buffers is referred to as a “Fast” connection because it is highly likely to be aligned, while the other type is referred to as a “Slow” connection. When a consumer establishes a connection, it specifies a connection type. The connection type can change from Fast to Slow and back. The invention reduces memory bandwidth, latency, error recovery using TCP retransmit and provides for a “graceful recovery” from an empty receive queue. The implementation also may conduct CRC validation for a majority of inbound DDP segments in the Fast connection before sending a TCP acknowledgement (Ack) confirming segment reception.

Abstract: A system and method for providing parallel implementation of a TCP sender comprising a transmit request handler and a transmitter. A transfer control protocol (TCP) transmission system is provided, comprising: a transmit request handler that receives request events, records the event information into a connection context and either schedules a connection in a ready queue or places the connection in a pending queue; and a transmitter that operates in parallel with the transmit request handler, wherein the transmitter dequeues connections from the ready queue and prepares packets for transmission based on information recorded in the connection context.

Abstract: In a computer network system that includes a multiplicity of nodes interconnected by a network of switches, wherein data are normally conveyed in the network according to predetermined conventions, a method for simulation testing of the system. One of the nodes is selected to serve as an error injector and injects data into the network in a manner that violates the predetermined conventions, so as to simulate an error condition in the system. Operation of the system is observed following the injection of the data so as to evaluate a response of the system to the error condition.

Abstract: In a computer network system that includes a multiplicity of nodes interconnected by a network of switches, each switch having multiple ports, a method for testing one of the switches includes assigning a respective one of the nodes to each of a plurality of the ports of the switch being tested. The network is configured so that the switch being tested is substantially isolated from data flow from and to the nodes in the network that are not assigned to the ports of the switch. Data are conveyed at a controlled rate between two or more of the assigned nodes through the respective ports, and behavior of the switch is observed in response to the data being conveyed.

Abstract: A method for diagnosis of a system made up of a plurality of interlinked modules includes receiving an alarm from the system indicative of a fault in one of the modules. Responsive to the alarm, a causal network is constructed associating the fault with malfunctions in one or more of the modules that may have led to the fault and relating a conditional probability of the fault to respective probabilities of the malfunctions. Based on the alarm and the causal network, at least one of the probabilities of the malfunctions is updated. A diagnosis of the alarm is proposed responsive to the updated probabilities.