Abstract: Methods are provided to monitor and report performance data of a device such as a data storage drive. A plurality of quantitative values are obtained from feedback and measurement mechanisms in a data storage device of a first model during operation of the storage device. The plurality of quantitative values are normalized. Then, one or more qualitative values are generated from one or more normalized quantitative values and evaluated against corresponding baseline performance values established for the first model.

Abstract: An unencoded m-bit data input sequence is divided into a block of n bits and a block of m?n bits. The block of n bits is divided into a first set of n+1 encoded bits, wherein at least one of P1 subblocks of the first set satisfies a G, M and I constraints. The first set of n+1 encoded bits is mapped into a second set of n+1 encoded bits wherein at least one of P2 subblocks of the second set gives rise to at least Q1 transitions after 1/(1+D2) precoding. A second set of n+1 encoded bits is divided into P3 encoded subblocks and the P3 encoded subblocks are interleaved among (m?n)/s unencoded symbols so as to form a (m+1)-bit output sequence codeword which is then stored on a data storage medium.

Abstract: A fully synchronous servo channel for a data tape drive is provided which includes the initial acquisition of synchronous servo channel parameters, generation of a timing basis for signal interpolation, generation of a tape velocity estimate and a y-position estimate and an optimum detection of longitudinal position (LPOS) symbols embedded in servo bursts.

Abstract: A method is provided to improve the efficiency of the transmission of consistency groups across multiple storage components by ensuring that volume transactions are evenly allocated among backup components. Each volume is initially assigned to a specified backup component. Once a color period begins, volume transactions are transmitted to the assigned backup component. Each backup component accumulates data transfer information for its assigned volumes throughout at least a portion of the color period and calculates a new volume assignment for the next color period. Before the start of the next color period, a captain storage controller transmits any new assignments to the backup components. During a next color period, the process is repeated using the new assignments.

Abstract: Method, apparatus and program product are provided for rebuilding faulty metadata in a storage controller coupled to a host device. Faulty metadata may include metadata which no longer matches the associated customer data tracks stored on a DASD or other storage device. When an error in metadata is describing a first customer track is detected, a range of other customer tracks in which the error is also likely to have occurred is identified. The metadata tracks associated with the first customer track and the other customer tracks are selected to be invalidated. A command is received through a host interface, and the specified metadata tracks are invalidated while the controller remains on-line with the host and continues to process other host I/O operations. Subsequently, the invalidated metadata tracks are rebuilt. The disclosed method, apparatus and program product invalidate the faulty metadata with reduced impact on normal host/controller I/O operations.

Abstract: A method for initiating a data storage facility recovery process in a data processing system having a first peer data storage facility and a second peer data storage facility communicating with the first peer data storage facility by a communication link. The method of initiating a recovery process is invoked by one peer data storage facility upon another peer data storage facility operating under a peer to peer remote copy (PPRC) protocol. Data copied from a first peer data storage facility to a second peer data storage facility is monitored for errors. Upon detection of an error by one peer data storage facility, recovery and data collection operations are initiated on the other peer data storage facility. Preferably, the initiation of recovery and data collection operations occurs out of band, over a second communication link between the peer data storage facilities.

Abstract: The present invention provides a novel method for determining the mechanical properties of the surfaces of materials including thin films. Generally, the method is comprised of laterally scanning the surface of the film with an array of cantilever tips varying temperature, load and time to obtain a measurement of mechanical properties, such as hardness and glass transition temperature. The method can be used to obtain mechanical properties of films that would otherwise be unobtainable using standard methods.

Abstract: A data storage domain is provided to determine a set of signal conditioning parameters for data being transmitted over smart cables in a data storage domain between an SAS switch and SAS expanders and among SAS expanders. A first expander interrogates any attached smart cables for cable persistent data and captures in a table the cable persistent data. One or more interfaces of the first expander are operated at a first data rate. The switch collects the captured cable persistent data and, in response, determines a set of signal conditioning parameters for data being transmitted on each attached smart cable. The set of signal conditioning parameters includes a first maximum data rate for each attached smart cable. The signal conditioning parameters are then set for each attached smart cable in accordance with the set of determined signal conditioning parameters, whereby the data storage domain is tuned for optimum signal transmission.

Abstract: A high density storage enclosure includes a plurality of storage devices, such as hard disk drives, positioned within a cooling airflow. Data to be stored to a storage device is received and a determination is made as to the expected usage of the data relative to other data stored on devices within the enclosure. The data is stored in a device having a position within the airflow relative to the source of the airflow in direct relationship to the relative expected usage of the data. Thus, data having a higher expected usage is stored in a device closer to the airflow source relative to other data having a lower expected usage and data having a lower expected usage is stored in a device farther from the airflow source relative to other data having a higher expected usage. Additionally, data may be dynamically relocated based upon actual usage.

Abstract: Method and apparatus are provided for encoding and decoding rate-(s(K+1)/s(K+1)+1) TCMTR(j,k,t,a) codes, where s is the ECC symbol size in bits and K is the number of unencoded symbols that are interleaved with an (s+1)-bit encoded block at the output of a rate-s/(s+1) encoder that encodes the r-th s-bit symbol. K=m/s?1 where m=s(K+1) is the total number of bits to be encoded. Error propagation is reduced, thus allowing the ECC code to correct errors efficiently. Header error-rate is also reduced by eliminating occurrence of likely error events at the detector output. Although initially an RLL code may be designed for an ECC symbol size of s bits, the RLL encoding of the present invention may be used in conjunction with ECC schemes that utilize symbol sizes other than s bits.

Abstract: A method of, apparatus for, or storage device medium having instructions for publishing a first notification within a data processing system where the data processing system comprises a first source generating the first notification, a first destination device, and a second destination device. The source may be a storage unit, a printer, a processing unit, or any other device which is a component of the data processing system. The destination device is typically a monitor, a workstation, a computer, a PC, or other input/output type workstation. The method comprises of having the first destination device subscribe to receive notifications from the first source. In addition, the second destination device subscribes to receive the notifications serially republished from the first destination device. Upon the publication of a notification from the first source to the first destination device, the first destination device will publish the notification to the second destination device.

Abstract: Methods and apparatus are provided for managing data in a hierarchal storage subsystem. A plurality of volumes is designated as a storage group for Level 0 storage; a threshold is established for the storage group; space is allocated for a data set to a volume of the storage group; the data set is stored to the volume; the threshold is compared with a total amount of space consumed by all data sets stored to volumes in the storage group. Data sets are migrated from the storage group to a Level 1 storage if the threshold is less than or equal to the total amount of space used by all of the data sets stored to volumes in the storage group. Thus, contention between migration and space allocation is reduced.

Abstract: A method for processing a point-in-time copy of data associated with a logical storage volume where the data to be copied is stored in a striped or parallelized fashion across more than one physical source volume. The method includes receiving a point-in-time copy command concerning a logical volume and distributing the point-in-time copy command in-band to each of the physical source volumes containing a portion of the striped data. The method also includes establishing a point-in-time copy relationship between each physical source volume and one of a corresponding set of multiple physical target volumes. The method further includes copying the data stored on each physical source volume to the corresponding physical target volume. The in-band copy command and the striped data may be distributed over I/O channels between a server and the physical storage and processed sequentially.

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: A dynamic selection of a communications link between a storage controller and one of a plurality of storage servers is provided so as to enhance the performance of the storage system. The storage system includes a plurality of storage devices, a corresponding plurality of virtual storage controllers coupled to the storage devices and a virtual storage controller. The virtual storage controller includes a host interface, a server interface, a stored table and a processing unit. The stored table includes a list identifying the active links between the server interface and each virtual storage server and, for each active link, a corresponding performance value.

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: A customizable cache discard policy is provided which reduces adverse consequences of conventional discard policies. In a data processing system, a cache controller invokes a cache data discard policy as the cache approaches its capacity. Using one possible policy, data having the shortest retrieval (fetch) time is discarded before data having longer retrieval times. In an alternative policy, data may be discarded based upon its source. Weightings may be applied based upon the distance from each source to the cache, may be based upon priorities assigned to each source, or may be based upon the type of each source.

Abstract: A fully synchronous servo channel for a data type drive is provided which includes the initial acquisition of synchronous servo channel parameters, generation of a timing basis for signal interpolation, generation of a tape velocity estimate and a y-position estimate and an optimum detection of longitudinal position (LPOS) symbols embedded in servo bursts.

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: Method, apparatus and program product are provided for the invalidation of faulty metadata in a storage controller coupled to a host device. Faulty metadata may include metadata which no longer matches the associated customer data tracks stored on a DASD or other storage device. When faulty metadata is detected, metadata tracks are selected to be invalidated. A command is received through a host interface, without the controller being taken off-line from the host, and the specified metadata tracks are invalidated. Subsequently, the invalidated metadata tracks are rebuilt. The disclosed method, apparatus and program product invalidate the faulty metadata with reduced impact on normal host/controller I/O operations.