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 storage system is provided which includes an internal local area network. The local area network is achieved by providing a separate Ethernet bus as well as Ethernet hardware on each host and disk/tape controller within the storage system. Each host controller and disk/tape controller is coupled to the Ethernet bus via the Ethernet interface hardware. Also coupled to the Ethernet bus is a service processor. The service processor is coupled to the Ethernet bus via an Ethernet hub. All communications between the service processor and the controllers occurs over the Ethernet bus. This allows communications with the controllers which does not materially impact the operation of the storage system in providing storage services to the attached host computers.

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 backup server controls the backing up of data stored on a mass storage subsystem in response to a backup request from a host identifying data to be backed up during a backup operation, the mass storage subsystem storing data in a plurality of mirrored copies. The backup server comprises a discovery module, a preparation module, an execution module and a clean-up module. The discovery module receives the backup request and identifies, during a discovery phase, at least one storage location on the mass storage subsystem on which data to be backed up during the backup operation is stored. The preparation module, during a preparation phase following the discovery phase, enables the mass storage subsystem to sever one of said mirrored copies and make it available to backup server for the backup operation.

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: 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: 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, a novel memory operation protocol may be used to facilitate the execution of memory operations in the memory system. These memory operations may include atomic read-modify-write operations that may involve arithmetic and/or logical operations of greater complexity than those that may be carried out in the prior art.

Abstract: A data network includes a switch that links a number of host processors to shared resources such as network ports of a cached storage subsystem. The switch routes resource requests from its inputs to selected ones of its outputs in accordance with programmed routing information. The routing information is changed dynamically based on measured loading characteristics of requests from the switch inputs or the respective hosts, in order to reduce the probability of blocked paths. In a specific example, respective subsets of output ports of the switch are assigned to each respective input port, the loading of each input port of the switch is measured, and the respective subset of output ports assigned to each input port are repetitively changed, and the respective subset of an input port is changed in response to blocking of the output ports assigned to the input port.

Abstract: A method and apparatus for controlling the unauthorized removal of software from a non-volatile storage medium include storing an encoded version of the software at an address of the storage medium where the address is used as data directly in the process of deriving an encoding key used to encode the software, and decoding the encoded software using a decoding key derived using the location of the software in its storage medium as data.

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 technique is provided for mapping mass storage device addresses to mass storage devices mounted in a mass storage device mounting system. The mounting system may include a single type of chassis that may contemporaneously mount two sets of disk mass storage devices. One of the sets of disk mass storage devices may comprise disk mass storage device that have a first form factor (e.g., half height form factor), and the other set may comprise disk mass storage devices that have a second form factor (e.g., LP form factor).

Abstract: There is disclosed an improved apparatus for manufacturing printed circuit boards which solves the problem of immersion bath contaminants being plated-out onto electrically-conductive, circuit functional pads, (board-features) by introducing into the bath system a mechanism for attracting those contaminants to non-functional “micro-thieves” which are electrically-conductive, non-circuit-functional pads having substantially smaller dimensions than those of the smallest board-feature, thereby taking advantage of previously unknown immersion bath uncontrolled strike phenomena, whereby the contaminants are directed to the micro-thieves and away from the board-features. Application of the micro-thieves in the immersion bath environment also produces plated features, of both finer and larger geometries, having flatter surfaces and a more uniform plated thickness for all features on the printed circuit board (PCB), than previously obtained.

Abstract: A redundant peripheral device subsystem in a computer system is disclosed including first and second peripheral device controllers. First and second peripheral device busses are coupled to the first and second peripheral device controllers, respectively. A controllable switch is coupled between the first and second peripheral device busses. The controllable switch either isolates the first and second peripheral device busses from each other, or joins them into a single peripheral device bus.

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: This invention is a data storage system that includes logic configured for carrying out a method to allow a so-called “re-labeling” of a logical volume. Re-labeling changes the label configuration originally put in place by the host at a first device and replicated to a second device. The re-labeling takes place during a certain operation that takes the second device offline to a host computer in communication with the data storage system. This re-labeling avoids labeling conflicts that could arise when duplicate labels result on two different devices as a result of the replication.