Abstract: Provided are a system and article of manufacture for bidirectional data transfer. In certain embodiments a link layer login is sent from a first port to a second port. Subsequently, an application layer login is sent from the first port to the second port to establish a first data path, wherein the first data path is from the first port to the second port. Subsequently, another application layer login is sent from the second port to the first port to establish a second data path, wherein the second data path is from the second port to the first port. In certain other embodiments, a first data path is established from a first port to a second port. A determination is made at the first port, whether the second port has a second data path established from the second port to the first port. An application layer logout is sent from the first port to the second port, in response to determining that the second port has the second data path established from the second port to the first port.

Abstract: A method for performing a data exchange between an initiator and a receiver in a fiber channel protocol (FCP) is provided. A control flag is set in a write command to indicate the presence of an identifier. The identifier is copied into a command descriptor block (CDB) of the write command and appended to a data frame. The write command and data frame, including the identifier, is sent from the initiator to the receiver.

Abstract: Provided are a system and article of manufacture, wherein in certain embodiments an I/O command from a host is received at a first storage unit. An identifier is generated that identifies a destination to which the I/O command is to be transmitted from the first storage unit. The I/O command is augmented with the generated identifier at the first storage unit. The augmented I/O command is transmitted. In certain other embodiments, an I/O command is received at a storage unit, wherein the storage unit is associated with a storage unit identifier. A determination is made at the storage unit, whether the I/O command is associated with an identifier that identifies a destination for which the I/O command is intended. A further determination is made, at the storage unit, whether the identifier is the same as the storage unit identifier, in response to determining that the identifier associated with the I/O command identifies the destination for which the I/O command is intended.

Abstract: A method for performing a data exchange between an initiator and a receiver in a fibre channel protocol (FCP) is provided. A control flag is set in a write command to indicate the presence of an identifier. The identifier is copied into a command descriptor block (CDB) of the write command and appended to a data frame. The write command and data frame, including the identifier, is sent from the initiator to the receiver.

Abstract: Provided are a method, system, and program monitoring paths between a first controller and second controller. A determination is made as to whether one path has been unavailable for a predetermined time period in response to detecting that the path is unavailable. Indication is made that the path is in a first failed state if the path has been unavailable for more than the predetermined time period and indication is made that the path is in a second failed state if the path has not been unavailable for the predetermined time period.

Abstract: Disclosed is a technique for assigning priorities. A request to manipulate data is received. A type of the request is determined. A priority is assigned to the request based on the type of the request.

Abstract: A first device determines a possibility of an invalidation of a second device, wherein the first device is coupled to the second device via a fabric. A query is sent from the first device to validate the second device, in response to determining the possibility of the invalidation of the second device. A determination is made, at the first device, whether to continue I/O operations from the first device to the second device based on receiving a response to the query within a time period.

Abstract: Provided are a method, system, and program monitoring paths between a first controller and second controller. A determination is made as to whether one path has been unavailable for a predetermined time period in response to detecting that the path is unavailable. Indication is made that the path is in a first failed state if the path has been unavailable for more than the predetermined time period and indication is made that the path is in a second failed state if the path has not been unavailable for the predetermined time period.

Abstract: A method is disclosed to transfer information from a first information storage and retrieval system to a second information storage and retrieval system. The method provides a first information storage and retrieval system comprising a first track size and a plurality of first tracks, and a second information storage and retrieval system comprising a second track size and a plurality of second tracks. The method determines if the first track size is greater than the second track size. If the method determines that the first track size is greater than said second track size, then the method sets a ratio (R) equal to the first track size divided by the second track size, provides the (i)th first track from the first information storage and retrieval system to the second information storage and retrieval system, provides (R) second tracks, and maps the (i)th first track onto the (R) second tracks.

Abstract: Provided are a method, system, and program for copying tracks between a primary controller and secondary controller. A track is received from the primary controller that is part of a copy job comprising a sequence of tracks to copy along with a sequence number of the received track and a context number identifying computational resources in the primary controller used to transmit the track, sequence number, and context number. The context number and sequence number transmitted with the track are used to determine if a track preceding the received track was written to storage. The secondary-controller writes the received track to storage if the track preceding the received track was written to storage.

Abstract: Provided are a system and article of manufacture, wherein in certain embodiments an I/O command from a host is received at a first storage unit. An identifier is generated that identifies a destination to which the I/O command is to be transmitted from the first storage unit. The I/O command is augmented with the generated identifier at the first storage unit. The augmented I/O command is transmitted. In certain other embodiments, an I/O command is received at a storage unit, wherein the storage unit is associated with a storage unit identifier. A determination is made at the storage unit, whether the I/O command is associated with an identifier that identifies a destination for which the I/O command is intended. A further determination is made, at the storage unit, whether the identifier is the same as the storage unit identifier, in response to determining that the identifier associated with the I/O command identifies the destination for which the I/O command is intended.

Abstract: Provided is a method, wherein in certain embodiments an I/O command from a host is received at a first storage unit. An identifier is generated that identifies a destination to which the I/O command is to be transmitted from the first storage unit. The I/O command is augmented with the generated identifier at the first storage unit. The augmented I/O command is transmitted. In certain other embodiments, an I/O command is received at a storage unit, wherein the storage unit is associated with a storage unit identifier. A determination is made at the storage unit, whether the I/O command is associated with an identifier that identifies a destination for which the I/O command is intended. A further determination is made, at the storage unit, whether the identifier is the same as the storage unit identifier, in response to determining that the identifier associated with the I/O command identifies the destination for which the I/O command is intended.

Abstract: Provided are a method, system and article of manufacture for bidirectional data transfer. In certain embodiments a link layer login is sent from a first port to a second port. Subsequently, an application layer login is sent from the first port to the second port to establish a first data path, wherein the first data path is from the first port to the second port. Subsequently, another application layer login is sent from the second port to the first port to establish a second data path, wherein the second data path is from the second port to the first port. In certain other embodiments, a first data path is established from a first port to a second port. A determination is made at the first port, whether the second port has a second data path established from the second port to the first port. An application layer logout is sent from the first port to the second port, in response to determining that the second port has the second data path established from the second port to the first port.

Abstract: Provided are a system and article of manufacture for bidirectional data transfer. In certain embodiments a link layer login is sent from a first port to a second port. Subsequently, an application layer login is sent from the first port to the second port to establish a first data path, wherein the first data path is from the first port to the second port. Subsequently, another application layer login is sent from the second port to the first port to establish a second data path, wherein the second data path is from the second port to the first port. In certain other embodiments, a first data path is established from a first port to a second port. A determination is made at the first port, whether the second port has a second data path established from the second port to the first port. An application layer logout is sent from the first port to the second port, in response to determining that the second port has the second data path established from the second port to the first port.

Abstract: Provided are a method, system, and program monitoring paths between a first controller and second controller. A determination is made as to whether one path has been unavailable for a predetermined time period in response to detecting that the path is unavailable. Indication is made that the path is in a first failed state if the path has been unavailable for more than the predetermined time period and indication is made that the path is in a second failed state if the path has not been unavailable for the predetermined time period.

Abstract: A method is disclosed to transfer information from a first information storage and retrieval system to a second information storage and retrieval system. The method provides a first information storage and retrieval system comprising a first track size and a plurality of first tracks, and a second information storage and retrieval system comprising a second track size and a plurality of second tracks. The method determines if the first track size is greater than the second track size. If the method determines that the first track size is greater than said second track size, then the method sets a ratio (R) equal to the first track size divided by the second track size, provides the (i)th first track from the first information storage and retrieval system to the second information storage and retrieval system, provides (R) second tracks, and maps the (i)th first track onto the (R) second tracks.

Abstract: Provided are a method, system and article of manufacture for bidirectional data transfer. In certain embodiments a link layer login is sent from a first port to a second port. Subsequently, an application layer login is sent from the first port to the second port to establish a first data path, wherein the first data path is from the first port to the second port. Subsequently, another application layer login is sent from the second port to the first port to establish a second data path, wherein the second data path is from the second port to the first port. In certain other embodiments, a first data path is established from a first port to a second port. A determination is made at the first port, whether the second port has a second data path established from the second port to the first port. An application layer logout is sent from the first port to the second port, in response to determining that the second port has the second data path established from the second port to the first port.