International Business Machines Corporation

Steven Jay Greenspan

Carl Edward Clark

Stephen Joseph Kinder

Juliet C Candee

Jeffrey Douglas Haggar

Joshua W Knight

David B Emmes

Danny R Sutherland

Alan Michael Webb

John L Czukkermann

Roger E Bonsteel

Casper A Scalzi

Kenneth E Plambeck

Hiren Ramlal Shah

Douglas Michael Zobre

Robert Vaughn Geiner

Jeffrey David Aman

Melvin R Zimowski

Patrick Michael Livecchi

Bernard R Pierce

Michael Gerard Mall

Juilet C Candee

Ricky L Kready

A system for porting code from a native platform to a non-native platform is provided which utilizes a non-native, platform-specific layer of code and a platform-neutral layer of code. The platform-neutral layer substantially emulates the native platform of ported code and provides a platform-neutral interface to the ported code. Together, the platform-specific layer and the platform-neutral layer provide an execution environment in which the ported code operates as a kernel extension of the non-native platform. The platform-neutral layer of the execution environment is portable to other non-native platforms so that code can be ported to another non-native platform by replacing the platform-specific layer with a customized platform-specific layer, which is adapted to the other non-native platform.

System and program product for porting code utilizing a portable execution environment

A system and program product for facilitating computing-environment control of a resource to be accessed by existing program code is provided which includes transparently replacing an uncontrolled resource referenced by existing program code with a resource controlled by a computing environment. The protocol also includes transparently interposing at least one resource management service of the computing environment between the existing program code and the resource controlled by the computing environment, wherein the at least one resource management service provides computing-environment control of the resource to be accessed by the existing program code. The replacing of the uncontrolled resource prevents the existing program code from directly accessing the resource.

System and program product for providing computing-environment control of a resource to be accessed by program code

A method of facilitating computing-environment control of a resource to be accessed by existing program code is provided which includes transparently replacing an uncontrolled resource referenced by existing program code with a resource controlled by a computing environment. The method also includes transparently interposing at least one resource management service of the computing environment between the existing program code and the resource controlled by the computing environment, wherein the at least one resource management service provides computing-environment control of the resource to be accessed by the existing program code. The replacing of the uncontrolled resource prevents the existing program code from directly accessing the resource.

Method for providing computing-environment control of a resource to be accessed by program code

A method of porting code from a native platform to a non-native platform is provided which utilizes a non-native, platform-specific layer of code and a platform-neutral layer of code. The platform-neutral layer substantially emulates the native platform of ported code and provides a platform-neutral interface to the ported code. Together, the platform-specific layer and the platform-neutral layer provide an execution environment in which the ported code operates as a kernel extension of the non-native platform. The platform-neutral layer of the execution environment is portable to other non-native platforms so that code can be ported to another non-native platform by replacing the platform-specific layer with a customized platform-specific layer, which is adapted to the other non-native platform.

Method, system and program product for porting code utilizing a portable execution environment

A secured subspace facility is provided for ensuring isolated storage for transactions running under an operating system main task. Isolation is achieved by attaching, from an operating system task, subtasks that will restrict application addressing. The attaching includes defining a subspace address environment as home space within a dispatchable unit access list (DU-AL) associated with each attached subtask. Multiple subtasks can be attached with each subtask running applications in an isolated address subspace, notwithstanding execution of the applications in address register addressing mode.

Storage isolation employing secured subspace facility

An exemplary embodiment of the invention is a method for providing a path-sensitive branch registry for cyclic distributed transactions. This method requires that a superior node's transaction manager (TM) identify itself as the root followed by sending the syncpoint cue to at least one subordinate node. Before sending the syncpoint cues to the subordinate the superior links the inbound messages with its specific branch qualifier (BQUAL) as well as a global transaction identifier (GTRID). The TM of each subordinate node receives syncpoint cues and is responsible for knowing who its superior is. In addition, the TM is responsible for recognizing the flow of branch instructions and guarantee that it uses a network-wide unique value for the branch values it generates for a given global transaction. With the recognition of the flow from the superior node the subordinate TM updates the node registry as to the inbound and outbound flow of branch messages by its superior and its subordinates.

Method for creating path-sensitive branch registry for cyclic distributed transactions

An exemplary embodiment of the present invention is a method for affinity free restart of a resource manager in a multi-system environment. The method begins when a restart request is received from a first resource manager on a first system in the multi-system environment. The first resource manager is associated with an incomplete transaction. Next, a distributed transaction unit of recovery structure is built for the incomplete transaction. Then, the distributed transaction unit of recovery structure is sent to a transaction manager for restart processing. The restart process includes restarting the first resource manager on the first system. The restart process also includes restarting a second resource manager on a second system in the multi-system environment if the incomplete transaction is associated with the second resource manager. The second system is a different system in the multi-system environment than the first system and the second resource manager previously had a node in common with the first resource manager. Additional embodiments include a system and storage medium for affinity free restart of a resource manager in a multi-system environment.

Method and system for removal of resource manager affinity during restart in a transaction processing system

The frequency at which a multisystem log stream is compressed by a system of a multisystem environment is adjusted in real-time. The rate at which the multisystem log stream is compressed by the system is ascertained. That rate is relative to how frequently the multisystem log stream is compressed by other systems of the multisystem environment. The frequency with which the system compresses the multisystem log stream is then adjusted in real-time. Thus, the frequency at which one system of the multisystem environment compresses the log stream is relative to the frequency at which other systems of the multisystem environment are compressing the log stream.

Pacing the frequency at which systems of a multisystem environment compress log streams

Syncpoint processing is performed for a distributed transaction. The distributed transaction includes a plurality of units of recovery, and syncpoint processing is performed for at least a portion of the units of recovery, without passing messages between the units of recovery of the at least a portion of the plurality of units of recovery. Instead, syncpoint processing (including transactional logging) is controlled by one syncpoint manager associated with one of the units of recovery, and that unit of recovery collects information representative of the other units of recovery.

Method, system and program products for providing efficient syncpoint processing of distributed transactions

Method of pacing the frequency at which systems of a multisystem environment compress log streams

Managing a log stream of a computer system. An entry of a log stream, desired to be removed from the log stream, but not eligible for removal, is logically deleted. Logical deletion keeps the entry on the log stream and indicates that the entry can be removed from the log stream when it is eligible. When the entry is eligible, it is removed. If a desired entry remains at the tail of the log stream for a given period of time, thus not all owing the removal of one or more undesired entries, the desired entry is rewritten to the head of the log stream and deleted from the tail. Thereafter, other logically deleted entries eligible for deletion are removed from the log stream.

System of compressing a log stream using a scratch pad of logically deleted entries

A system and method for processing a request utilizing a database management system in a computer system is disclosed. The database management system manages at least one database. At least one database subsystem corresponding to the database management system is available. The computer system includes a plurality of worker threads. The method and system include assigning the request to a worker thread of the plurality of worker threads. The worker thread is for aiding in execution of the request. The method and system also include providing a connection to a particular database subsystem for the worker thread and associating the connection with the worker thread if the worker thread has not previously used the particular database subsystem. The method and system further include reusing the connection to the particular database subsystem that is associated with the worker thread if the worker thread has previously used the particular database subsystem.

Method and system for managing connections to a database management system

Program products for pacing the frequency at which systems of a multisystem environment compress log streams

Six instructions for the manipulation of discontinuous memory locations in a computer memory are described. They are: Compare and Load (CL), Compare and Swap (CS), Double Compare and Swap (DCS), Compare and Swap and Store (CSST), Compare and Swap and Double Store (CSDST), and Compare and Swap and Triple Store (CSTST). In each instruction a processor associates a programming-specified blocking symbol with a lock not accessible to software. The lock is used by any of these instructions only during its single instance of instruction execution, and the lock is made available (unlocked) at the end of each instance to then enable another blocking-symbol instruction instance to use the lock, thereby serializing concurrent multiple processor requests for accessing the same resource. Programming associates resources in a system with the unique blocking symbols. Each instance of these instructions executes an operand earlier prepared from a data value taken from the resource.. The data value is checked for change during the instance of execution when equality indicates no change since its preparation. These blocking-symbol instructions significantly increase the computer's speed of changing noncontiguous locations in a resource, compared to the time needed by software-protocol locks which must operate over a plurality of instances to make corresponding changes in a resource.

Method utilizing a set of blocking-symbol resource-manipulation

A multisystem log stream of a multisystem environment is compressed. The oldest record needed for each system that can write or delete entries from the multisystem log stream is tracked, and that information is used in compression of the log stream. The block ids associated with those oldest records are maintained within a vector, and when the vector is updated, a determination is made as to whether the entry in the vector that it replaced previously contained the lowest block id in the vector. If so, all the records having block ids lower than the new lowest block id in the vector are deleted.

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Hyde Park, NY, United States of America

Steven Jay Greenspan