Abstract: Provided are a method, system, and article of manufacture, wherein a request is received for switching a logical volume from one state to another state, wherein the logical volume is in a mirrored state if data corresponding to the logical volume is mirrored from a first storage to a second storage, and wherein the logical volume is in a non-mirrored state if the data corresponding to the logical volume is not mirrored from the first storage to the second storage. A determination is made as to whether to perform the switching, in response to receiving the request.

Abstract: An apparatus, system and method are disclosed for storing modified data. The apparatus includes a battery source for supplying backup power. The apparatus also includes a memory module for storing data. The memory module includes a backup portion and a non-backup portion. Only the backup portion is backed up by the battery source in the event of a power failure. A data flow module controls data flow into and out of the memory module. The data flow module stores modified data exclusively in the backup portion of the memory module.

Abstract: A computer storage system includes a supervisor algorithm to detect a host computer's initiator logging in. The supervisor algorithm identifies data storage devices associated with the newly logged-on initiator and tags logical unit number control blocks (“LUNCBs”) as having priority in an initiation process. The supervisor algorithm assigns a task control block to each of the identified data storage devices and invokes a logical unit number (“LUN”) initialization algorithm. If the supervisor algorithm was invoked during an initial microcode load (“IML”) event, the LUN initialization algorithm initializes each of the identified data storage devices. However, if the supervisor algorithm was invoked during a warmstart procedure, the LUN initialization algorithm first checks to make sure the LUNCB was not mistakenly written too. If not, the LUN initialization algorithm terminates without initializing the associated data storage device.

Abstract: Provided are a method, system, and program for reassigning storage volumes from a failed processing system to a surviving processing system. A first processing system detects a failure of a second processing system. The first processing system determines device groups of storage devices managed by the failed second processing system and determines for each determined device group, hosts that connect to storage devices in the device group. The first processing system sends, for each device group, a unit check to each determined host indicating failure of each device group through one storage device in the device group to which the determined host connects. The determined hosts execute instructions to terminate any I/O operations in progress on the storage devices in the device group in response to the unit check indicating failure of one storage device in the device group and issue, a command to one storage device for the device group to end the busy condition.

Abstract: Provided are a method, system, and program for initiating and using information used for a host, control unit, and logical device connections receiving a request to create a host port to control unit port connection. In a volume group data structure, a volume group entry is defined having a plurality of pointers for the host port and control unit port pair. At least one device address is added to the volume group that is accessible to the host port and control unit port connection by initializing at least one pointer in the volume group entry to address at least one device data structure. For each of the at least one device addresses, indication is made in the at least one device data structure addressed by the at least one pointer in the volume group entry that the device address is accessible to the host port and control unit port connection.

Abstract: Provided are a method, system, and program for an adaptor to read and write to system memory. A plurality of blocks of data to write to storage are received at an adaptor. The blocks of data are added to a buffer in the adaptor. A determination is made of pages in a memory device and I/O requests are generated to write the blocks in the buffer to the determined pages, wherein two I/O requests are generated to write to one block split between two pages in the memory device. The adaptor executes the generated I/O requests to write the blocks in the buffer to the determined pages in the memory device.

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 managing volumes in volume groups configured in a storage system. A first set of volumes is assigned to a first volume group and a first host is assigned to the first volume group. A second set of volumes is assigned to a second volume group and a second host is assigned to the second volume group. The first host may only access volumes in the first volume group and the second host may only access volumes in the second volume group, wherein one volume is assigned to both the first and second volume groups to be accessible to both the first and second hosts.

Abstract: Provided are a method, system, and article of manufacture, wherein a command is received at a first computational device coupled to a first adapter that is capable of allowing access to a data storage to the first computational device. The first computational device sends the command to a second computational device. The command is processed by a second adapter coupled to the second computational device, wherein the second adapter allows the second computational device to access the data storage, and wherein the second adapter accesses memory in the first computational device to process the command. In certain embodiments, the first adapter that allows the first computational device to access the data storage has failed.

Abstract: Provided are a method, system, and program maintaining and using nexus information on a host, port and device connection. A login is received from a host port on a storage controller port, wherein the host port has been configured on the storage controller to access one or more devices. An entry is added to a host-storage controller ports data structure for the host port and storage controller port involved in the login. At least one pointer is initialized in the entry in the host-storage controller ports data structure to point to at least one entry in at least one intermediate data structure. One pointer is initialized in each entry in one intermediate data structure addressed by one initialized pointer in the host-storage controller ports data structure to point to a nexi data structure having a plurality of entries.

Abstract: Computer networks are provided with a resource efficient ability to generate link performance statistics. To calculate the average link utilization per I/O operation, a first counter accumulates the number of I/O operations processed by a link and a second counter accumulates the time required by the link to complete each I/O operation. The second value is then divided by the first value. The number of operations per second for a link may be computed by dividing the first number by a predetermined period of time and the average number of operations using the link may be computed by dividing the second number by the predetermined period of time. A third counter may be employed to accumulate the number of bytes transferred by a link during each I/O operation. Then, average size of an I/O operation may be computed by dividing the third number by the first number and the average bandwidth per link operation may be computed by dividing the third number by the predetermined period of time.

Abstract: A disk management server (“DMS”), to manage a remote storage device; a wireless communication network; and a mobile computer create a system for secure remote booting of a mobile computer's operating system. To facilitate access to remote boot code, a multiple connection disk management server utilizes a trusted connection to negotiate communication security and an untrusted connection for transferring data once communication security has been established. The trusted connection is established through a physically securable interface, such as a wired network or line-of-site wireless network, e.g., infrared. Successful negotiation of communication security produces a security key that can be utilized to secure information exchange over the untrusted network. The untrusted connection may utilize any standard wireless communication protocol such as IEEE 802.11b.

Abstract: A method to update a data structure is disclosed. The method receives a write thread, and sets a data structure indicator to indicate that the data structure is unusable. The method creates (N) thread indicators, and assigns each of said (N) indicators to a different one of said (N) threads. Upon return to the thread dispatcher, the (i)th thread sees the data structure indicator which shows that the data structure is unusable. The method then sets the (i)th thread indicator to indicate that upon subsequent dispatches the (i)th thread will see the data structure indicator that shows that the data structure is unusable. After each of the (N) threads has seen the data structure indicator marking the data structure as unusable, the method sets the data structure indicator to indicate that the data structure is invalid, updates the data structure, and sets the data structure indicator to indicate that the data structure is valid.

Abstract: An apparatus, system, and method are disclosed for fastload code update on a communications adapter. The apparatus includes an image load module, a memory initialization module, and an image overlay module. The image load module is configured to load a copy of a new code image in a memory on the communications adapter. The memory also concurrently stores a copy of an old code image used by the communications adapter. The memory initialization module is configured to invoke the new code image to perform a memory initialization operation. The memory initialization module may perform the memory initialization operation concurrently with ongoing I/O requests possibly accepted, but not necessarily processed, by the old code image. The image overlay module is configured to overlay the old code image with the new code image. The fastload code update minimizes the time that the communications adapter is off-line to overlay the old code image with the new code image and reinitialize the communications adapter.

Abstract: Methods, system and computer program product are provided to improve the efficiency of data transfers in a PPRC environment. Any or all of three features may be implemented, each of which reduces the number of round trips required for the exchange of handshaking, data and control information. A first feature includes disabling the “transfer ready” acknowledgment which normally occurs between a primary storage controller and a secondary storage controller. A second feature includes pre-allocating payload and data buffers in the secondary storage controller. A third feature includes packaging write control information with a write command in an extended command descriptor block (CDB). Such a step eliminated the need for a separate transmission of the write control information. The CDB is transmitted along with a data block from the primary storage controller to the secondary storage controller and placed in the respective, pre-allocated buffers. Data may also be pipelined to the secondary.

Abstract: A method to control access to logical volumes disposed in an information storage and retrieval system using parallel access volumes. The method provides an information storage and retrieval system comprising a plurality of logical volumes, and a plurality of host computers, where each host computers is capable of communicating with the information storage and retrieval system. The method creates a parallel access volume having an alias, and persistently associates that parallel access volume with an original base logical volume, where the original base logical volume may be assigned to one of (N) logical volume groups. If the original base logical volume is assigned to the (i)th logical volume group, the method permits each host computers assigned to the (i)th host computer group to access the original base logical volume, or the current base logical volume, associated with the parallel access volume.

Abstract: Provided are a method, system, and article of manufacture, wherein in certain embodiments 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: An apparatus, system, and method are provided for updating a code image. The apparatus, system, and method include a loader for loading a new code image into a temporary memory location separate from the memory location occupied by the old code image. A conversion module of the new code image executes and selectively reconciles incompatibilities between the old code image and the new code image. In one aspect, once incompatibilities are reconciled, a copy module copies the new code image into the memory space occupied by the old code image.

Abstract: A method to control access to logical volumes. The method provides a plurality of host computers and an information storage and retrieval system comprising a plurality of logical volumes. The method forms (N) host computer groups, assigns one or more of the host computers to the (i)th host computer group, such that each host computer assigned to (i)th host computer group is not assigned to any other of the (N) host computer groups. The method forms (N) logical volume groups, assigns one or more logical volumes to the (i)th logical volume group, such that each of the logical volumes assigned to the (i)th logical volume group is not assigned to any other of the (N) logical volume groups. The method maintains a database associating the (i)th host computer group with the (i)th logical volume group, and permits a host computer assigned to the (i)th host computer group to access a logical volume assigned to the (i)th logical volume group.

Abstract: An apparatus, system, and method are disclosed for communicating binary data using a self-descriptive binary data structure. The binary data structure also may be referred to as a microcode reconstruct and boot (MRB) image. The binary data structure includes a plurality of data segments, a target data set, and a data structure descriptor. Each of the data segments has a data segment header and data field. The target data set is stored within the data field and may be an executable. The data structure descriptor is descriptive of the binary data structure and identifies the location of the target data set within the data field. The binary data structure is self-descriptive in that the location of an individual target data set may be identified by the data structure descriptor.