International Business Machines Corporation

Roger E Hough

Ching-Yun Chao

Amal Ahmed Shaheen

Peter H Gum

Leslie W Wyman

Suzanne M John

Jeffrey Paul Kubala

Kenneth J Oakes

Marten J Halma

Kenneth J Fredericks

David E Stucki

Robert E Murray

James C Mazurowski

Moon Jung Kim

Robert Edward Galbraith

Beth A Glendening

Casper A Scalzi

Donald W McCauley

Ira Glenn Siegel

Jonel George

Stephen J Schmandt

John Fenton Scanlon

John C Rathjen, Jr

Norman Ehsan Shafa

Rodolfo Augusto Mancisidor-Landa

Javashree Ramanathan

James Edward Bostick

Mark S Farrell

Charles Franklin Webb

Liana Liyow Fong

Phil C Yeh

Paul Gregory Greenstein

John Ted Rodell

Tushar Deepak Chandra

Mark Steven Squillante

Allan Samuel Meritt

Joseph C Elliott

Ronald M Smith

Kenya Ishimoto

Martin W Sachs

Charles E Shapley

Allen H Preston

Richard Roland Guyette

Richard Cwiakala

Patrick M Gannon

Frank W Brice

Vincent A Spano

Lucina L Green

Terry L Borden

Francis E Johnson

Assaf Marron

Daniel Ming-Te Hsieh

Thomas O Curlee, Iii

Peter H Tallman

Masao Nishimoto

Paul A Malinowski

David W Hollar

George H Bean

Steven Messinger

Norman C Chou

Michael Burrill Phillips

Pamela H Dewey

Sandra L Rankin

Devon S Yu

Stephanie W Zhang

Karen Udy

Mark E Rakhmilevich

Karen M Noonan

Fumiaki Abe

Kozo Sawada

Akio Saitoh

Kazuo Iimura

Karen Udy Chang

Goroh Sasaki

William J Glynn

Manohar R Rao

Miriam P Brown

Donald W Mccauley

John C Rathjen

John F Scanlon

A method and apparatus for providing a recent set of replicas for a cluster data resource within a cluster having a plurality of nodes. Each of the nodes having a group services client with membership and voting services. The method of the present invention concerns broadcasting a data resource open request to the nodes of the cluster, determining a recent replica of the cluster data resource among the nodes, and distributing the recent replica to the nodes of the cluster. The apparatus of the present invention is for providing a recent set of replicas for a cluster data resource. The apparatus has a cluster having a plurality of nodes in a peer relationship, each node has an electronic memory for storing a local replica of the cluster data resource. A group services client, which is executable by each node of the cluster, has cluster broadcasting and cluster voting capability. A database conflict resolution protocol ('DCRP'), which is executable by each node of the cluster, interacts with the group services clients such that the DCRP broadcasts to the nodes a data resource modification request having a data resource identifier and a timestamp. The DCRP determines a recent replica of the cluster data resource among the nodes with respect to the timestamp of the broadcast data resource modification request relative to a local timestamp associated with the data resource identifier, and distributes the recent replica of the cluster data resource to each node of the plurality of nodes.

Error detection protocol

A method and apparatus for providing a recent set of replicas for a cluster data resource within a cluster having a plurality of nodes; each of the nodes having a group services client with membership and voting services. The method broadcasts a data resource open request to the nodes of the cluster, determines a recent replica of the cluster data resource among the nodes, and distributes the recent replica to the nodes of the cluster. The apparatus is for providing a recent set of replicas for a cluster data resource. The apparatus has a cluster having a plurality of nodes in a peer relationship; each node has an electronic memory for storing a local replica of the cluster data resource. A group services client, which is executable by each node of the cluster, has cluster broadcasting and cluster voting capability. A database conflict resolution protocol (&ldquo;DCRP&rdquo;), which is executable by each node of the cluster, interacts with the group services clients such that the DCRP broadcasts to the nodes a data resource modification request having a data resource identifier and a timestamp. The DCRP determines a recent replica of the cluster data resource among the nodes with respect to the timestamp of the broadcast data resource modification request relative to a local timestamp associated with the data resource identifier, and distributes the recent replica of the cluster data resource to each node of the plurality of nodes.

Apparatus and method for maintaining consistency of shared data resources in a cluster environment

Within a computer cluster usage reference counts are maintained for replicated databases within a computer cluster using cluster membership and cluster voting services. Such a method includes the maintaining of a local reference count for all open distributed data resources within a given node, tracking by a group services client of those nodes that have the open distributed data resources, and using cluster membership services to update the local reference counts for node failures.

Apparatus and method for tracking access to data resources in a cluster environment

A method for replicating data in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Thereafter, a highest origination sequence number is sent from the central hub back to each originating node.

Method and system for replicating data in a distributed computer environment

A method of replacing a current version of a program module with a replacement version of the module concurrently with the execution of the program on a computer system. For each entry point within the current version of said module to which the program may make address reference, a corresponding entry point within the replacement version of the module is determined. While execution of the program is suspended, each address reference in the program to an entry point within the current version of the module is replaced with an address reference to the corresponding entry point within the replacement version of the module. Execution of the program is resumed when each address reference to the current module has been replaced with one to the replacement module.

Concurrent patch to logical partition manager of a logically partitioned system

Method, system and computer program for replicating data in a distributed computed environment

A node failure recovery mechanism for use in a data replicating system in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Upon failure of a node, a node failure recovery method may be used to enable a &ldquo;buddy&rdquo; node to help the failed node gain readmission to a distribution group.

Node failure recovery in a hub and spoke data replication mechanism

A method of scheduling jobs to be executed by a resource in a computer system wherein the jobs are grouped in &ldquo;classes.&rdquo; The job classes vying for the resource's attention are arranged in a hierarchy. Each job class has a time-function value that controls when the job class is selected by the resource if processing time becomes available. Within a particular level of the hierarchy, scheduling priorities are defined by one or more time-based functions, each of which may be constant or dynamically varying. When constant time-based functions are used, each job class has a schedule value that remains fixed with time. When dynamic time-based functions are used, job class &ldquo;time-function values&rdquo; are modified to alter the timing by which the job class(es) acquire the resource.

Computer resource proportional utilization and response time scheduling

A dynamic reconfiguration request for a change in a system's physical configuration is transmitted from a configuration controller to a hypervisor controlling operating systems executing in one or more partitions of the system. The hypervisor translates the physical reconfiguration request into a request for reconfiguration of logical resources known to the operating systems, first verifying it against an installation policy, and passes the requests to the operating systems in the partitions. The operating systems perform logical reconfiguration, then request physical reconfiguration of the hypervisor. The hypervisor initiates the physical reconfiguration through the configuration controller.

System and method for dynamically performing resource reconfiguration in

An external time source is connected to a partitioned data processing system, having host processors controlled by a host hypervisor, and having operating systems in the partitions. The host processors each have a timer facility comprising a time-of-day (TOD) clock, and a clock comparator. When the hypervisor detects a need for synchronization between the external time source and a host timer facility, it insulates the operating system in the partition on that host from host synchronization, and synchronizes the host timer facility with the external time source. Subsequently, the operating system is placed into normal execution, with an adjustment value used for timer facility references, and with a synchronization interrupt pending if the operating system is aware of the external time source.

System for synchronizing logical clock in logical partition of host

Enables any OS of plural OSs within any of plural logical-resource partitions (LPARs) of a CEC to use interpretive execution for synchronously-executable CHSC (channel subsystem call) commands. A CHSC command authorization mask (CCAM) is provided to control which CHSC commands are allowed to execute interpretively (with pass-through), and which commands are executed with hypervisor intervention (as all prior CHSC commands did). By enabling interpretive execution of those commands which can successfully operate with pass-through, significant system efficiency is obtained. And by disabling interpretive execution for a subset of CHSC commands (which are not allowed to execute with pass-through) potential system failures may be prevented. Thus, interpretive execution may be restricted differently among the OSs in a CEC. Novel CHSC command execution now handles multiple images of shared I/O resources by use of image identifiers, which could not be done before. The information requested by any OS issuing a CHSC command is filtered and optionally compacted by the I/O subsystem responding to the command by only providing information obtained from control blocks associated with the OS which issued the command. This is done by having a set of control blocks for each I/O resource, each control block in the set being associated with a particular OS.

Pass-through for I/O channel subsystem call instructions for accessing

A data processing system operating under a multiprocessing hypervisor program subject to I/O interrupts during a polling interval of the hypervisor program includes one or more processors for executing the hypervisor program and host system and one or more guest systems under the hypervisor program, a storage system connected to the processor's by a bus for storing instructions, data and control information associated with the systems being executed by the processor, the storage system may be partitioned into a number of separate areas each associated with one of the concurrently operating systems, an input/output subsystem for generating I/O interrupts to the processors, apparatus for testing to determine if the system is operating in an interpretive execution mode, apparatus for determining whether a dedicated region facility is active, apparatus for testing whether an I/O enablement mask for a guest system has been set, apparatus for setting a flag if the guest system I/O enablement mask is set, apparatus for testing the flag during each polling interval of the interpretive execution mode, apparatus for loading a control byte from a host control register into a hardware register if the flag has not been set and a count threshold reached, apparatus for testing for host system I/O interrupts and apparatus for switching to the host system if the host system interrupt is present.

Multiprocessing system including gating of host I/O and external

This invention involves reconfiguration support for shared I/O resources in a a computer electronic complex (CEC) supporting both shared and unshared I/O channels of the type described and claimed in U.S. patent application Ser. No. 07/898,867 (PO9-92-016) filed on the same day as the subject application and assigned to the same assignee as the subject application. Prior channel subsystem call (CHSC) instructions cannot execute when a channel is to be configured as shareable by plural operating systems in a CEC.

Asynchronous command support for shared channels for a computer complex

Provides a method for increasing the connectivity of I/O resources to a multiplicity of operating systems (OSs) running in different resource partitions of a computer electronic complex (CEC) to obtain sharing of the I/O resources among the OSs of the CEC, including channels, subchannels (devices), and control units (CUs). The invention provides image identifiers (IIDs) for assigning resources to the different OSs. Each shared I/O resource has a sharing set of control blocks (CBs) in which a respective CB is assigned to (and located by) a respective IID of one of the OSs. Each of the CBs in a sharing set provides a different image of the same I/O resource. The different CB images are independently set to different states by I/O operations for the different OSs, so that the OSs can independently share the same I/O resource.

Method and means for sharing I/O resources by a plurality of operating

A system and method for dispatching logical central processing units (CPUs) among physical CPUs in a multiprocessor computer system having multiple logical partitions, wherein the cryptographic facilities may not be interchangeable. According to the present invention, the logical CPUs are dispatched among the physical CPUs according to either an affinity, floating, or disabled scheduling method. The affinity scheduling method is used when the crypto facilities are not interchangeable or when non-interchangeable crypto functions are performed. The floating scheduling method is used when the cryptographic facilities are interchangeable and interchangeable crypto functions are performed. The disabled scheduling method is used when the logical CPU is not authorized to issue cryptographic instructions.

Scheduling normally interchangeable facilities in multiprocessor

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Highland, NY, United States of America

Roger E Hough