Abstract: An error handling method is provided for processing adapter errors. Rather than executing a disruptive controller hardware reset, an error handling routine provides instructions for a reset operation to be loaded and executed from cache while the SDRAM is in self-refresh mode and therefore unusable.

Abstract: When data is stored in many storage subsystems, metadata, such as a sequence number, is also generated and stored with the data. When the data is accessed, the metadata is checked to ensure that the desired data element has been accessed. In conventional storage subsystems, data elements, such as logical blocks, are stored sequentially in logical pages of each logical volume. Consequently, sequence numbers closely correlate with block positions within the physical pages and sequence number/position patterns tend to repeat frequently and access errors may not be detected. Algorithms are provided to calculate new, offset, physical block positions which reduce the close association of sequence numbers and physical positions, thereby reducing such aliasing. The algorithms incorporate the logical volume number, the logical page number, or both, in addition to the logical block number. As a result, detection of access errors becomes more likely.

Abstract: A feature key is provided to enable a specific feature in a target system, such as an IBM® Enterprise Storage Server®. The key includes fields identifying at least a portion of a serial number of the target system, identifying the feature on the target system to be enabled, and identifying a quantity associated with the feature to be enabled. Including the serial number ensures that the feature key will enable the feature on only the designated system and including the quantity ensures that only the quantity (of storage space, for example) paid for by the customer will be enabled. Additional fields may also be included identifying a storage architecture on which the feature is to be enabled, identifying a machine on which the feature is to be enabled, and identifying a sequence of prior feature keys generated for the feature on the target system.

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: Systems, methods and a computer program product are provided to permit the identification of all of the devices of a specified domain in a multi-domain environment. All communication among the domain devices is in-band having the advantage that no additional cabling is required. A control center between host devices and the domains receives an in-band command from an initiating device in a specified domain, the command being transmitted in response to the activation of a triggering device on the initiating device. Upon receipt of the command, the control center broadcasts an in-band command to each of the other devices in the domain directing the other devices to activate an indicator on each of the other devices. With the indicators on the devices in the specified domain activated, an administrator is able to identify those devices and thus focus his search for the faulty device only on those devices within the domain.

Abstract: Methods, systems, computer program products and methods for deploying computing infrastructure for clearing metadata in a storage subsystem. The method includes identifying one or more metadata tracks to clear, receiving a request from a client to clear the identified tracks, quiescing any active processes, clearing the identified tracks and resuming the quiesced processes. The request may be a single request operable to clear all metadata tracks. Alternatively, target volumes having metadata tracks to be cleared are identified and a request is received from a client for each target volume. A dynamic function list may also be created for each target volume, the list including list of functions in which the target volume is associated. After active processes are quiesced, each function in the dynamic function list of each target volume is invoked whereby the metadata tracks are cleared. The quiesced processes are then resumed.

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: Methods, systems, computer program products and methods for deploying computing infrastructure for managing metadata in a storage subsystem are provided. A first metadata track is staged from disk storage to a cache storage after which a journal entry is stored in a nonvolatile storage (NVS). The journal entry includes an opcode and update data for the track. The opcode identifies the type of update to be performed and the number of tracks to be updated in the operation. Each of the other metadata tracks is staged and a corresponding journal entry stored. The journaled updates are then applied to the respective metadata track in the cache storage and the tracks destaged from cache to the disk storage.

Abstract: Method for selectively clearing persistent data such as metadata in a storage subsystem. The method includes identifying one or more metadata tracks to clear, receiving a request from a client to clear the identified metadata tracks, passing the request to a storage device driver, and clearing the identified metadata tracks. The metadata tracks to be cleared may be identified by a specific storage function associated with the metadata to be cleared or by a specific storage target associated with metadata. Alternatively, both a storage function and a storage target may be specified. Preferably, the request to clear one or more identified metadata tracks may be executed without affecting unrelated storage functions. In addition, the request may be executed while preserving metadata tracks unrelated to the identified metadata tracks.

Abstract: Methods, systems, computer program products and methods for deploying computing infrastructure for managing metadata in a storage subsystem are provided. A call is received from a client to update a portion of a metadata track. Data is also received from the client identifying at least one field of the metadata track to be updated, associated update values for the at least one field to be updated and an update type for the at least one field. A data structure field of a client interface is then populated with the identity of the at least one field and the associated update values and an opcode field of the client interface is populated with the update type. A task control block (TCB) is then allocated to the client call and, at the direction of the TCB, various operations are performed without further activity by the client. The metadata track may also be validated before being updated to ensure that the client has access only to valid updates.

Abstract: A data processing unit including a first active cooling device configured to respond to a first control signal and a second active cooling device configured to respond to a second control signal. The control signals may be any type of control signal suitable to control the operation of the first and second active cooling devices. The data processing unit also includes a first control function selectively capable of providing the first control signal and/or the second control signal, and a second control function selectively capable of providing the first control signal and/or the second control signal. Logic associated with the first and second control functions is included to determine which of the control functions will provide which control signal at a specific time. Logic and/or switching or isolation apparatus is also included to prevent both the first and second control functions from attempting to provide one of the control signals simultaneously.

Abstract: A method, controller, program product and service are provided for more efficiently managing a resource queue. Two or more queues are configured to handle workloads of various sizes. Resource elements are allocated from the top of each queue and returned to the bottom. The size of each queue may be selected to provide sufficient resource elements to handle a system's various levels of workload. As the workload increases and all of the resource elements in the one queue are allocated, new resource elements are allocated from the top of the next queue and returned to the bottom. When the workload decreases, resource elements are no longer allocated from the queues used for higher workloads. Thus, retention of historical data in the queues is enhanced while efficient cache utilization is maintained.

Abstract: A method of transmitting information from a primary storage control unit to a secondary storage control unit in an asynchronous data copying system. The method includes building multiple descriptor blocks for transmission from the primary storage control unit, and encrypting multiple payloads according to one of n encryption methods. In addition, the n encryption methods are associated with the primary storage control unit and n decryption keys relating to the n encryption methods are associated with the secondary storage control unit. An index to the n encryption keys is associated with the multiple descriptor blocks. The method further includes encrypting each of the payloads according to one of the n encryption methods and indicating, in the index associated with a selected descriptor block, which decryption key relates to the encryption method used for any payload associated with a select descriptor block.

Abstract: In a computer network environment, a server protocol is provided to process read requests from clients. Rather than all read requests being processed synchronously or all read requests being processed asynchronously, an attempt is first made to perform a synchronous read. If the synchronous read is unsuccessful, the connection through which the request was received by the server is registered with a monitoring service. When the data is ready to be read, an appropriate callback is called and the data transmitted. An optional delay may be imposed before the synchronous read is attempted to increase the likelihood that the attempt will be successful. A series of delays/read attempts may also be employed in order to increase the likelihood still further that an attempt will be successful.

Abstract: The state or condition of a system may be evaluated by comparing a set of selected parameter values, converted into a trial vector, with a number of model or exemplar vectors, each of which was represents a particular state or condition of a sample system. Examples of such conditions may include “good”, “marginal”, “unacceptable”, “worn”, “defective”, or other general or specific conditions. Sets of parameter values from the system are converted into input vectors. Unprocessed vectors are then processed against the input vectors in an artificial neural network to generate the exemplar vectors. The exemplar vectors are stored in a memory of an operational system. During operation of the system, the trial vector is compared with the exemplar vectors. The exemplar vector which is closest to the trial vector represents a state which most closely represents the current state of the system.

Abstract: The state or condition of a data storage drive, or a subsystem within a drive, may be evaluated by comparing a set of selected parameter values, converted into a trial vector, with a number of model or exemplar vectors, each of which was represents a particular state or condition of a sample drive. Examples of such conditions may include “good”, “marginal”, “unacceptable”, “worn”, “defective”, or other general or specific conditions. Sets of parameter values from the drive are converted into input vectors. Unprocessed vectors are then processed against the input vectors in an artificial neural network to generate the exemplar vectors. The exemplar vectors are stored in a memory of an operational drive. During operation of the drive, the trial vector is compared with the exemplar vectors. The exemplar vector which is closest to the trial vector represents a state which most closely represents the current state of the drive.

Abstract: In a power controller or other computing resource shared by multiple processors, an ID is written to the lock register, thereby designating a master processor. A timer is then initialized to count for a predetermined period. Periodically, the master processor transmits a “heartbeat” signal to the shared resource, indicating that its operation remains normal. Upon receipt of the heartbeat signal, the timer is reset and begins a new count for the predetermined period. If the timer reaches the end of the period without having received a heartbeat signal, indicating that the master processor has failed or hung, the lock register is cleared again and an interrupt signal is broadcast to all of the processors. The processors compete for master status anew and, when an ID is successfully written to the lock register, the timer is restarted and the new master periodically transmits its heartbeat signal.

Abstract: A method, apparatus, and article of manufacture containing instructions for the management of data in a point-in-time logical copy relationship between a source and multiple target storage devices. The method consists of establishing first and second point-in-time logical copy relationships between a source storage device and at least two target storage devices concerning an extent of data. Upon establishment of the point-in-time copy relationships, a first cache scan request is received relating to the first point-in-time logical copy relationship to remove a first extent of data from cache; a similar cache scan request is received related to the second point-in-time logical copy relationship. The first cache scan request is processed, and the successful completion of both the first cache scan request and the second cache scan request is returned to the storage controller upon the processing of only the first cache scan request.

Abstract: A method, apparatus, and article of manufacture containing instructions for processing multiple point-in-time consistent data sets. The method consists of creating multiple point-in-time data sets associated with a backup appliance which is associated with backup storage. Upon the transfer of a first update from a primary storage controller to the backup appliance, a determination is made whether the update affects data stored in the backup storage has been unchanged following the creation of the respective data sets. If the update does affect data which is unchanged following the creation of a data set, the current, non-updated data is read from the backup storage. A copy of the current, non-updated data thus read from the backup storage is stored in a storage location which can be one of the data sets or an independent memory location. In addition, pointers are associated with the remaining applicable data sets and directed to the copy at its 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.