International Business Machines Corporation

Kenneth M Nagin

William Frank Micka

Yoram Novick

Oded Cohn

Alexander Winokur

Michael Howard Hartung

Efraim Zeidner

Claus William Mikkelsen

John N McCauley, Jr

Julian Satran

Vernon John Legvold

John Norbert McCauley

Benny Rochwerger

Pnina A Vortman

Nimrod Rotics

Udi N Rotics

Itamar Gilad

Elfraim Zeidner

A data transmission system, including a plurality of transmitters for transmitting a stream of multiplexed packets over a broadband channel, the packets being constructed from a stream of variable length data blocks, each of the blocks originating from different sources. The system also includes a plurality of receivers for receiving the stream of packets from the broadband channel and reconstructing the stream of variable length data blocks. The data blocks are distributed over one or more packets. The packets also include a packet header having a source identifier (SID) for identifying the source of the packet, and the first of the packets further including a block header having a block identifier (BID) for identifying the data block being transmitted.

Data transmission system based upon orthogonal data stream mapping

A method and system are disclosed for enhanced efficiency of backup copying of designated datasets stored within a plurality of storage devices coupled to the data processing system via a storage subsystem control unit having subsystem memory therein. Application execution within the data processing system is temporarily suspended long enough to form a dataset logical-to-physical system address concordance to be utilized to administer copying of the designated dataset. Thereafter, application initiated updates to uncopied portions of the designated datasets are temporarily deferred until sidefiles of the affected portions of the designated datasets are written to subsystem memory. The updates are then written to the storage subsystem. Portions of the designated datasets are then accessed and copied from the storage subsystem on a scheduled or opportunistic basis utilizing selected data retrieval command sequences. A sidefile status query is appended to selected data retrieval command sequences and the presence of data within the subsystem memory is determined without the necessity of additional communications between the data processing system and the storage subsystem. The sidefiles are then accessed and copied. Copied portions of the designated datasets and sidefiles are then copied to alternate storage locations in a backup copy order defined by the address concordance.

Method and system for sidefile status polling in a time zero backup copy process

A method and apparatus for improving storage controller throughput when servicing non-specific read requests. Throughput is increased by enabling the storage controller to service non-specific read requests issued against a device address which is not the same as the device address associated with the data that the non-specific read is requesting. The device address associated with the data is thus free to be used for another I/O operation. When the device address used by the non-specific read is a non-busy type (that is, the device and/or data is not locked) then the throughput improvement is obtained by increasing the number of data requests that may be concurrently handled by the storage controller.

Locking a non-busy device for accessing a data record stored on another

A data backup copying session on a data processing system is secured responsive to initiation of the data backup session by an application executing on a processing unit by generating a unique identifier for the data backup session. Thereafter, all member paths of a group of paths designated by the processing unit for communication between itself and the first storage subsystem are identified and associated with the data backup session. Access to the session is thereafter allowed only along a member path of the group of paths associated with the data backup session. The system and method of the invention further provide for fault recovery and protection against excessive demand on storage control unit memory.

Method and system for time zero backup session security

A method and system for efficiently accessing desired datasets among multiple datasets which are stored at specific data addresses within multiple storage subsystems which are coupled to a host system via a storage subsystem controller and a data channel. A data request is transmitted from the host system to the storage subsystems via the data channel. The data request specifies non-address attributes for desired datasets, such as boundary addresses for large data extents including many datasets or a request for all datasets modified since the occurrence of a specified event. The data request is then processed at the storage subsystem controller to determine a data address for each dataset within the storage subsystem which possess the desired attributes. Thereafter, the desired datasets are transmitted via the data channel to the host system in association with a specific address for each dataset. A selected status message is transmitted from the storage subsystem controller when no more datasets are located which possess the desired attributes. In this manner, the retrieval of data from a storage subsystem is greatly enhanced.

Method and system for non-specific address data retrieval in a data

A method and system are disclosed for permitting high concurrency of access during backup copying of designated data stored within a storage subsystem which includes multiple storage devices coupled to the data processing system via a storage subsystem control unit having subsystem memory therein. Data within each storage device is accessed utilizing a Unique Control Block (UCB), which identifies a selected storage device, and an associated data retrieval command sequence which identifies the data to be accessed. Portions of the data copied to subsystem memory within the subsystem storage control unit as sidefiles from a first storage device may be accessed utilizing a Unique Control Block (UCB) associated with an alternate storage device by associating a selected data retrieval command sequence therewith which identifies the data as stored within the subsystem memory. In this manner, data from a first storage device may be accessed utilizing an alternate Unique Control Block (UCB), permitting concurrent access of data utilizing the Unique Control Block (UCB) associated with the first storage device.

Method and system for concurrent access during backup copying of data

A method and system are disclosed for transferring a backup copy of designated datasets stored in a plurality of storage subsystems to a host system via a data channel during concurrent execution of an application. Upon receiving a request for a backup copy, execution of an application is temporarily suspended. A dataset logical-to-physical storage system address concordance for the designated datasets is formed and execution of the application is resumed thereafter. Any application initiated updates to affected portions of the designated datasets which occur prior to generation of a backup copy of the affected portions of the datasets are processed by buffering the updates, copying the affected portions to storage subsystem memory, updating the address concordance and writing the updates to the affected portions of the dataset. The remaining portions of the designated datasets are then copied to storage system memory from the storage subsystem on an asynchronous basis and an attention signal is transmitted to the host system when a lower threshold level is achieved. If an upper threshold level within the storage subsystem memory is achieved, the asynchronous copying of the designated datasets is temporarily suspended. The stored portions of the designated datasets are then transferred from storage subsystem memory to the host system at channel speeds, greatly enhancing the efficiency of data transfer.

Growing community of inventors

Tucson, AZ, United States of America

Kenneth M Nagin