Abstract: A cabinet having a plurality of rack mountable chassis. One portion of such chassis has directors and electrically interconnected memory and another portion of such chassis has a plurality of disk drives. The plurality of chassis are electrically interconnected to provide a data storage system interface. A first one of such chassis includes a memory and a plurality of directors. A first plurality of the directors is adapted for coupling to a host computer/server. A second one of such chassis has a plurality of disk drives. Also includes are first electrical conductors for connecting the disk drives in the second chassis to a second plurality of directors in the first one of the chassis. A third one of such chassis includes a memory and a plurality of directors. The first plurality of the directors in the third one of the chassis are adapted for coupling to the host computer/server. A fourth one of such chassis has a plurality of disk drives.

Abstract: Mechanisms and techniques allow a data storage system to detect errors in data received for storage within the data storage system. To do so, the data storage system receives, from an originator application operating on a server computer system, portions of data which comprise an application data block which is to be written to storage in the data storage system. In conjunction with the data received at the data storage system, the data storage system also receives application error checking information which the originator application generates on the data within the application data block. The application error checking information may be, for example, checksum information embedded within one or more portions of the data which comprise the application data block. Upon receipt of the data and the application error checking information, the data storage system generates data storage error checking information on the data within all portions of data which comprise the application data block.

Abstract: A digital data storage system in the form of a mass storage subsystem in which information is stored on one or more disk storage units, with a storage element constituting a track on a disk storage device and each track storing a plurality of records. Each track in each disk storage device of the digital data storage system is associated with a descriptor. When the control device retrieves the contents of a record, it can process the contents to generate a check value and compare the generated check value with the check value for the record as stored in the descriptor associated with the track. If they compare appropriately, the control device can determine that the record that was retrieved was, in fact, the record that was to be retrieved. On the other hand, if they do not compare appropriately, the control device can determine that the record that was retrieved was not the proper record.

Abstract: A method and apparatus for enabling an on-line reconfiguration of striped data in a disk array storage device. A replicated copy of the striped logical device is made in parallel with host operations. A logical device with a new configuration is then substituted for access by the host application even before any data is transferred to locations within the newly configured logical device. Independent processes operating in this disk array storage device reconfigure the data transparently to any host operations while accommodating host I/O requests directed to locations in the new configuration.

Abstract: Storing data in a cache memory of a storage device includes providing access to a first segment of the cache memory on behalf of a first group of external host systems coupled to the storage device and providing access to a second segment of the cache memory on behalf of a second group of external host systems coupled to the storage device, where at least a portion of the second segment of the cache memory is not part of the first segment of the cache memory. In some embodiments, no portion of the second segment of the cache memory is part of the first segment. Storing data in a cache memory of a storage device may also include providing a first data structure in the first segment of the cache memory and providing a second data structure in the second segment of the cache memory, where accessing the first segment includes accessing the first data structure and accessing the second segment includes accessing the second data structure. The data structures may be doubly linked ring lists of blocks of data.

Abstract: A method and apparatus for manipulating data in a storage device that is coupled to a host computer. Manipulations that can be performed by the storage device include moving non-contiguous blocks of data between the host computer and the storage device in a single operation. Other manipulations can be performed directly by the storage device without passing data to or from the host computer and include copying data from one logical object that is defined on the host computer to another, initializing, backing-up, transforming, or securely deleting a logical object that is defined by the host computer with a single command. In one embodiment, an application programming interface is provided that allows a relationship between logical objects on a host computer and storage locations on a storage device to be communicated between the host computer and the storage device.

Abstract: A method and apparatus for manipulating data in a storage device that is coupled to a host computer. Manipulations that can be performed by the storage device include moving non-contiguous blocks of data between the host computer and the storage device in a single operation. Other manipulations can be performed directly by the storage device without passing data to or from the host computer and include copying data from one logical object that is defined on the host computer to another, initializing, backing-up, transforming, or securely deleting a logical object that is defined by the host computer with a single command. In one embodiment, an application programming interface is provided that allows a relationship between logical objects on a host computer and storage locations on a storage device to be communicated between the host computer and the storage device.

Abstract: A memory manager for use in connection with a memory comprises a memory access request receiver module, an address translation module and a memory access operation control module. The memory access request receiver module is configured to receive an access request requesting an access operation in connection with the memory, the access request including an address.

Abstract: Disk array storage device apparatus for enhancing the performance of an application on a data processing system that operates with a disk array storage device in which the completion of tasks associated with different transactions with one logical storage device are conditions precedent to the completion of other transactions. Specific tasks related to the one logical device are given priority over tasks related to all other logical storage devices. In a specific implementation reconnect tasks are given the highest priority with reconnect tasks from the one logical storage device being given the highest priority. A second category of tasks related to the one logical storage device can be given priority over all other tasks except reconnect tasks. All other tasks are given a priority below that of the first and second task categories.

Abstract: A method for enabling overlapped input/output requests to a logical device using assigned and parallel access unit control blocks. Each I/O request interrupts an operating system to assign a base and related unit control block to the input/output requests. In addition a parallel access control block is associated with each unit control block for a logical volume and a parallel access main control block is established with a logical volume through which each of the base and related unit control block can be identified. An input/output request to a logical device interrupts the operating system to assign one of the base and one of the assigned unit control blocks to the input/output requests after which control transfers back to the operating system. At a disk storage facility, the input/output request is located in a table with other input/output requests and corresponding parameters.

Abstract: A system interface includes a plurality of first directors, a plurality of second directors, a data transfer section and a message network. The data transfer section includes a cache memory. The cache memory is coupled to the plurality of first and second directors. The messaging network operates independently of the data transfer section and such network is coupled to the plurality of first directors and the plurality of second directors. The first and second directors control data transfer between the first directors and the second directors in response to messages passing between the first directors and the second directors through the messaging network to facilitate data transfer between first directors and the second directors. The data passes through the cache memory in the data transfer section. A method for operating a data storage system adapted to transfer data between a host computer/server and a bank of disk drives.

Abstract: Storing data in a cache memory of a storage device includes providing access to a first segment of the cache memory on behalf of a first group of external host systems coupled to the storage device and providing access to a second segment of the cache memory on behalf of a second group of external host systems coupled to the storage device, where at least a portion of the second segment of the cache memory is not part of the first segment of the cache memory. In some embodiments, no portion of the second segment of the cache memory is part of the first segment. Storing data in a cache memory of a storage device may also include providing a first data structure in the first segment of the cache memory and providing a second data structure in the second segment of the cache memory, where accessing the first segment includes accessing the first data structure and accessing the second segment includes accessing the second data structure. The data structures may be doubly linked ring lists of blocks of data.

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 and apparatus for enabling an on-line reconfiguration of striped data in a disk array storage device. A replicated copy of the striped logical device is made in parallel with host operations. A logical device with a new configuration is then substituted for access by the host application even before any data is transferred to locations within the newly configured logical device. Independent processes operating in this disk array storage device reconfigure the data transparently to any host operations while accommodating host I/O requests directed to locations in the new configuration.

Abstract: A method for enabling a data processing system with a host running under an operating system and with a disk array storage device organized by logical devices to processes plural I/O requests from one or more host processors concurrently.

Abstract: A method for enabling a data processing system with a host running under an operating system and with a disk array storage device organized by logical devices to processes plural I/O requests from one or more host processors concurrently.

Abstract: Storing data in a cache memory of a storage device includes providing access to a first segment of the cache memory on behalf of a first group of external host systems coupled to the storage device and providing access to a second segment of the cache memory on behalf of a second group of external host systems coupled to the storage device, where at least a portion of the second segment of the cache memory is not part of the first segment of the cache memory. In some embodiments, no portion of the second segment of the cache memory is part of the first segment. Storing data in a cache memory of a storage device may also include providing a first data structure in the first segment of the cache memory and providing a second data structure in the second segment of the cache memory, where accessing the first segment includes accessing the first data structure and accessing the second segment includes accessing the second data structure. The data structures may be doubly linked ring lists of blocks of data.

Abstract: A method for enhancing the performance of an application on a data processing system that operates with a disk array storage device in which tasks associated with different transactions with one logical storage device are conditions precedent to the completion of other transactions. Specific tasks related to the one logical device are given priority over tasks related to all other logical storage devices. In a specific implementation reconnect tasks are given the highest priority with reconnect tasks from the one logical storage device being given the highest priority. A second category of tasks related to the one logical storage device can be given priority over all other tasks except reconnect tasks. All other tasks are given a priority below that of the first and second task categories.

Abstract: Two data storage systems are interconnected by a data link for remote mirroring of data. Each volume of data is configured as local, primary in a remotely mirrored volume pair, or secondary in a remotely mirrored volume pair. Normally, a host computer directly accesses either a local or a primary volume, and data written to a primary volume is automatically sent over the link to a corresponding secondary volume. Each remotely mirrored volume pair can operate in a selected synchronization mode including synchronous, semi-synchronous, adaptive copy—remote write pending, and adaptive copy—disk. Direct write access to a secondary volume is denied if a “sync required” attribute is set for the volume and the volume is not synchronized.

Abstract: A method and apparatus for enabling an on-line reconfiguration of striped data in a disk array storage device. A replicated copy of the striped logical device is made in parallel with host operations. A logical device with a new configuration is then substituted for access by the host application even before any data is transferred to locations within the newly configured logical device. Independent processes operating in this disk array storage device reconfigure the data transparently to any host operations while accommodating host I/O requests directed to locations in the new configuration.