Abstract: A memory system and method of using same are provided. In one embodiment of the present invention, the memory system may include a plurality of logic sections that may be used to facilitate execution of relatively complex atomic read-modify-write operations.

Abstract: A process that swaps physical storage volumes. The process performs a number of simple arithmetic operations to find a seek time for B new states of a disk. The number is of order B. Each new state is related to a current state of the disk by a swap with a selected external storage volume. The process also includes swapping one of the storage volumes of the disk with the selected storage volume in response to determining that the state produced by the swap has a smallest seek or access time among the new states.

Abstract: A data transfer arrangement transfers data from a source device, such as a local mass storage facility, to a destination device, such as a remote storage facility. The data transfer arrangement comprises a source device and a destination device. The source device transfers to the destination device a data block including data and padding along with a source check value that is a function of the data and selectively the padding, and a check indication indicating whether the check value is the function of the data alone, or the data and the padding. The destination device, after receiving the data block, source check value and check indication, generates a destination check value that is the function of the data alone, or the data and the padding, based on the check indication, and uses the source and destination check values to determine whether the data block was correctly received.

Abstract: In a system that includes a back-up subsystem comprising back-up media, a mass storage subsystem connected to the back-up subsystem, and a host connected to the mass storage subsystem, the mass storage subsystem, as master and independent of the host, requests the restore operation by providing to the back-up subsystem, as slave, data identifiers identifying multiple data items to be transferred during the restore operation. The back-up subsystem determines its preferred ordering for retrieval of the requested plurality of data items from the back-up media. The back-up subsystem provides the requested data items to the mass storage subsystem in the determined preferred order in a plurality of iterations, each iteration identified by a data item identifier for the data item to be transferred in the current iteration.

Abstract: Queued lock services for managing a shared resource in a data processing system include a cooperative lock override procedure. On detecting a protocol failure by another processor, the detecting processor confirms that the failing processor is the lockholder and passes the lock to the next requestor in the queue.

Abstract: A lock for managing shared resources in a data processing system enables a requesting processor, in a signal atomic transaction, to validate the main lock data structure, request a lock, take the lock and establish a lock mode if successful, or establish its place in a queue of requesters for subsequent locks on the shared resource if unsuccessful.

Abstract: A queued, multimodal, fault-tolerant lock mechanism for managing shared resources in a data processing system is provided. Lock override procedures are selectively associated with certain lock modes.

Abstract: A system and method for determining whether activity graphs (hereinafter “graphs”) for logical volumes of data storage are correlated. A number of correlation criteria are applied to the graphs, including the area ratio criteria determines whether an area ratio described by the graph is at least as great as a predetermined value; the peak ratio criteria indicates that one graph is correlated to another graph if a peak ratio described by the two graphs is as large as a predetermined peak ratio value; and the sharp peak criteria indicates in the event that one graph is correlated to another graphs having at least one coincidental peak. Different combinations of all or some of the disclosed correlation criteria and the traditional correlation coefficient may be used to determine whether graphs of logical volumes are correlated, the level of correlation, and how “strong” of a correlation exists between the graphs.

Abstract: A process performs an intra-disk swap. The process includes finding a set of values indicative of access loads of new states of a disk. Each new state is produced from a current state of the disk by hypothetically swapping a pair of physical storage volumes of the disk. The process also includes performing the swap of a pair of physical storage volumes based on the value of the access load of the new state produced by hypothetically swapping the pair.

Abstract: A memory storage device has a file storage operating system which uses an inode to record and find segments of each data file. The inode includes a plurality of rows. A portion of the rows are written with direct extents pointing to data blocks storing portions of file segments. At least two of the extents point to data blocks having addresses in different logical volumes.

Abstract: A mass storage business continuance time maker function host system that allows one or more MVS mainframe hosts to have the time to: establish business continuation volumes to mirror the standard mass storage volumes; synchronize business continuation volumes with the standard volumes so that their contents are identical; split off a business continuation volume from its standard volume counterpart to make the business continuation volume available for other purposes; and enable a business continuation volume to be used to restore the contents of a standard volume—all without halting or disrupting the business applications using standard volumes. These and related services are provided in a transparent manner to a host mainframe by manipulating MVS format volume labels, volume tables of contents and indexes, catalog entries, data set names and similar mechanisms on mass storage devices connected to host mainframes using the MVS operating system.

Abstract: A process determines a seek time of an access head of a physical storage disk. The process includes collecting statistical access data on physical storage volumes served by the access head and determining seek times for a set of reference head travel time functions. Each function depends on distances between pairs of the physical storage volumes. The process also includes performing a sum of the determined seek times. Each term of the sum is weighted by an expansion coefficient of a travel time function of the access head with respect to the set of reference head travel time functions.

Abstract: A queued, multimodal, self-validating lock mechanism selectively associates supplemental validation procedures with certain lock modes. Only those lock modes which heavily drain system resources are extensively validated.

Abstract: A method balances workloads of storage devices of a storage subsystem. The method includes reading a mailbox to obtain control parameters and collecting historical data on numbers of accesses to storage volumes of the storage devices. The control parameters are written in the mailbox by host devices. The method also includes selecting data swaps that lead to better balanced workloads for storage devices based on the historical data. The act of selecting and/or the act of collecting being initialized by the control parameters.

Abstract: The invention features a method and a system for selecting a slot within a memory unit, e.g., cache, for removal. The memory unit is accessible to a plurality of processors, and each slot in the memory unit has a corresponding entry in an age table. Each time when a processor examines one of the entries, an age value of the entry is increased. When the age value is above a maturity age, the corresponding slot becomes a removable slot. Each processor also maintains statistics to estimate the number of removable slots in the memory unit. According to the statistics, adjusts a maturity age associated with the processor dynamically and independently to control the number of removable slots. Accordingly, the number removable slots can be maintained at a pre-determined percentage relative to the total number of slots in the memory unit.

Abstract: A memory system and method of using same are provided. In one embodiment of the present invention, the memory system may include a plurality of logic sections that may be used to facilitate execution of relatively complex atomic read-modify-write operations.

Abstract: A digital data storage system comprises a storage device, a descriptor memory and a control device. The storage device stores a series of records, the records being organized in a plurality of tracks, each track being associated with one of a plurality of cylinders. The descriptor memory stores a descriptor associated with storage device. The descriptor contains selected information relating to the records stored by the at least one storage device. Each descriptor includes a plurality of cylinder portions each configured to store selected information relating to a respective one of the cylinders in the storage device. Each cylinder portion, in turn, includes a plurality of track descriptors each configured to store selected information relating to a respective one of the tracks in the respective cylinder. The storage device also stores the descriptor associated therewith, the cylinder portions of the descriptor being augmented with additional information relating to the respective ones of the cylinders.

Abstract: A method checks a swap's quality. The method includes finding an upper bound for reductions to a disk's seek time or total access time. The reductions are caused by swapping single storage volumes of the disk, which is in a preselected state, with an external storage volume. The method also includes finding a reduction to the seek time or total access time produced by swapping one storage volume of the disk with a selected external storage volume and comparing the found reduction to the upper bound.

Abstract: A host system for remote control of mass storage volumes using cascading commands which collect information about linked remote volumes located in physically separate sites so other cascading commands can be issued to effect changes in linked remote volumes. A host computer program issues the cascading commands which ask the locally communicating mass storage system to return information which can be used to identify one or more levels of remote mass storage systems in a stream of remote mass storage systems. Once a mass storage system at a given level has been identified, commands can be sent by the host through the locally communicating mass storage system to cause actions to occur at the identified remote level, whether or not there are multiple intervening levels of remote mass storage systems.

Abstract: A storage system has a storage controller connected to a plurality of storage devices. The described system and method transfer physical data from a first storage device to a second storage device. The method does not involve a host computer in the physical data transfer thereby saving both computer CPU time and system bandwidth. The method receives an internal copy command from a commanding processor (the host) over a controller input path, reads at least one block of data, in data block format, from the first storage device, stores the requested data in a volatile memory in the controller, and sets a state of the pending stored data as a write pending state. The controller then destages the write pending memory stored data to the second storage device.