Abstract: A data coherence system includes a generation number written to a data track of a logical sub-system. The generation number is compared to a corresponding generation number in a processing device when it is initialized. If the two generations numbers are the same, the generation numbers are incremented and saved. If not, cache associated with the logical sub-system residing within the processing device is erased and the generation numbers are reset.

Abstract: Provided are a method, system, and article of manufacture, wherein a controller receives encrypted data from a first storage unit coupled to the controller. The received encrypted data is stored in a second storage unit coupled to the controller, wherein the controller is capable of accessing the second storage unit faster in comparison to the first storage unit. The encrypted data is maintained in the second storage unit, until at least one condition is satisfied.

Abstract: A method for storing customer data at a non-volatile storage (NVS) at a storage server. A track buffer is maintained for identifying first and second sets of segments that are allocated in the NVS. A flag in the track buffer identifies which of the first and second sets of segments to use for storing customer data for which a write request has been made. The customer data is stored in the NVS in successive commit processes. Following a power loss in the storage server, the NVS uses the track buffer information to identify which of the first and second sets of segments was involved in the current commit process to allow the current commit process to be completed.

Abstract: A method is disclosed to reconfigure a storage array disposed in a data storage system. The method supplies a data storage system comprising a plurality of data storage devices, wherein each of the plurality of data storage devices is assigned to one of a plurality of data storage arrays, or is assigned as a spare device. The method then detects an unassigned data storage device, and determines if any of the plurality of data storage arrays comprises a degraded data storage array. If the method determines that any of the plurality of data storage arrays comprises a degraded data storage array, then the method determines if the unassigned data storage device can be used to restore the degraded data storage array to optimal reliability, optimal performance, and optimal efficiency.

Abstract: Provided are a method, system and program for selecting a path comprising ports on primary and secondary clusters to use to transmit data at a primary volume to a secondary volume. A request is received to copy data from a primary storage location to a secondary storage location. A determination is made from a plurality of primary clusters of an owner primary cluster for the primary storage location, wherein the primary clusters are configured to access the primary storage location. A determination is made as to whether there is at least one port on the owner primary cluster providing an available path to the secondary storage location. One port on the owner primary cluster is selected to use to copy the data to the secondary storage location in response to determining that there is at least one port on the owner primary cluster available to transmit to the secondary storage location.

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: An apparatus, system, and method are disclosed for mandatory end to end integrity checking. The apparatus may include a compatibility module configured to monitor data from a source and verify integrity information compatibility with a standard, and an integrity module configured to wrap the data from the source with additional integrity information. The system may include a source configured to send data over a network, a target configured to receive data over the network, the apparatus, a main memory module, a storage controller, and a storage device. The method includes monitoring data from a source, verifying integrity information compatibility with a standard, and wrapping the data from the source with additional integrity information.

Abstract: A method, apparatus and program storage device for maintaining data is provided that includes receiving primary data at a first node, receiving mirrored data from a second and third node at the first node, and mirroring data received at the first node to a second and third node.

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: An apparatus, program product and method guarantee a period of time in which a partition's use of a resource will not be preempted by a hypervisor. An inquiry communication from the partition prompts the hypervisor to determine if work is pending for the hypervisor. If not, the hypervisor sends a guarantee response ensuring the period of uninterrupted use of the resource by the partition.

Abstract: A data coherence system includes a generation number written to a data track of a logical sub-system. The generation number is compared to a corresponding generation number in a processing device when it is initialized. If the two generations numbers are the same, the generation numbers are incremented and saved. If not, cache associated with the logical sub-system residing within the processing device is erased and the generation numbers are reset.

Abstract: Data management systems, such as used in disk control units, employ memory entry lists to help keep track of user data. Improved performance of entry list maintenance is provided by the present invention. Much of the protocol employed to conduct such maintenance is preferably performed by hardware-based logic, thereby freeing other system resources to execute other processes. New entries to the memory list are only allowed at predetermined addresses and entries are updated by writing a predetermined data pattern to a previously allocated address. Optionally, improved error detection, such as a longitudinal redundancy check, may also be performed in an efficient manner during entry list maintenance to assure the integrity of the list.

Abstract: Provided is a method, system, deployment and program for resource allocation unit queuing in which an allocation unit associated with a task is classified. An allocation unit freed as the task ends is queued for use by another task in a queue at a selected location within the queue in accordance with the classification of said allocation unit. In one embodiment, an allocation unit is queued at a first end of the queue if classified in a first class and is queued at a second end of the queue if classified in said second class. Other embodiments are described and claimed.

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 of verifying the passage of a data write across a bus is provided including sending the data write from an originator across the bus to a target, counting the number of data entries received at the target with a counter, and transmitting a return echo write from the target across the bus to a return address. The method further includes attaching the counter value to other data associated with the return echo write and polling the return address. The method allows determination of the completion of a data write by comparing the number of data entries included in the data write with the counter value polled from the return address. Alternatively, in a data streaming environment the progress of a data write may be determined by comparing the number of data entries included in the data write at a select point in time with the counter value polled from the return address. Typical data entries which are counted may include, but are not limited to, bytes, words, double words, or similar data quantities.

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 processing complexes to access shared devices. A lock to a plurality of shared devices is maintained and accessible to a first and second processing systems. The first processing complex determines a first delay time and the second processing complex determines a second delay time. The first processing complex issues a request for the lock in response to expiration of the first delay time and the second processing complex issues a request for the lock in response to expiration of the second delay time.

Abstract: Provided are a method, system and article of manufacture, wherein a first application executes at least two threads corresponding to a simultaneous multi-threaded processor whose resources have been acquired by the first application. The at least two threads are synchronized before releasing the simultaneous multi-threaded processor to a second application.

Abstract: An information storage and retrieval system is disclosed, wherein that information storage and retrieval system comprises a storage controller, comprising one or more host adapter ports, one or more device adapter ports, a processor, and a Fibre Channel switch. The information storage and retrieval system further comprises a Fibre Channel switch controller consisting essentially of a Fibre Channel switch and a processor. The system further comprises a plurality of data storage devices, where each of those data storage devices is interconnected with the storage controller and with the Fibre Channel switch controller.

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.