Unisys Corporation

Michael J Hill

Dennis R Konrad

Thomas P Cooper

Thomas L Nowatzki

Ralph E Sipple

Eugene J Gretter

John C Horton

Robert E Swenson

Thomas N Turba

Daryl J Kress

James F Torgerson

Barbara A Christensen

John R Jordan

Joseph E Kessler

Kenneth L Reising

Anthony P vonArx

Donald T Bordsen

Robert F Esson

A dynamic document template having static data, dynamic data, and/or procedural statements may be called by an application on a server. The dynamic document template is separate from the application program and is processed to form an interim script, which is then executed by a host computer system. The script generates document records in HTML or XML format that are output to a document. The data and procedural statements in the dynamic document template may be distinguished through interpreting mark-up language surrounding the data and procedural statements. The dynamic document templates execute in a separate namespace from the application and preserve the state of data in the application. A given application may call more than one dynamic document template to generate different portions of the output document. Additionally, the dynamic document templates may be replaced with new templates without affecting the application.

Scripted dynamic document generation using dynamic document template scripts

An apparatus for and method of efficiently accessing shared JavaScript objects within a multi-user environment by reducing the overhead required to maintain object/database property synchronization. A version is associated with each object to indicate whether any particular requested access is associated with the most current properties of the object. Each user has a version list which indicates whether any particular object properties need be updated before access. The version list is maintained in faster and more available memory than the actual object to enhance efficiency.

Method and apparatus for synchronizing dataset object properties with underlying database structures

An apparatus for and method of accommodating an XML document within a legacy data base management system. The XML document is defined by a Document Type Definition (DTD). The XML document is converted into a form suitable for use by the legacy data base management system in accordance with an Input Definition Table (IDT). The IDT is a table containing a plurality of sequential text statements which define the conversion process. The IDT is stored within a repository of the legacy data base management system.

XML input definition table for transforming XML data to internal format

Method and apparatus for tracking messages and transactions communicated between a number of users and a number of hosts, where the hosts are executing concurrent applications. During a first user session, a first user communicates with a first host. A counter associated with the first user session is incremented when the application creates an output message. The counter is decremented when the output message is released to the first user. A flag associated with the first user session is set and the counter is incremented once the flag is set, if an input message or committing transaction is received from the first user. The flag is cleared and the counter is decremented when the input message or committing transaction is processed by the concurrent application. The counter being decremented indicates there are no dependencies during the first user session with regard to the output message, input message, or committing transaction. If a second user session is initiated with a second host, the second host determines if there are any dependencies with the first user session. A dependency exists if the output message is created but not released, or if the input message or committing transaction is received but not processed. If there are dependencies, the first user session is reestablished to resolve the dependencies, otherwise, the second session is continued.

Protecting duplicate/lost updates against host failures

An apparatus and method of efficiently recovering from physical disk drive (or logical file) failures in transaction based digital data processing systems. As transactions are sequentially processed, compacted audit trail records are prepared to indicate modifications resulting from each transaction. The audit trail records are stored in storage areas on a disk drive in accordance with the physical data base disk drive(s) or logical file(s) to which the corresponding transaction refers. A physical disk drive or logical file is dumped to magnetic tape whenever the associated audit trail storage area is full, thus clearing the audit trail storage area for further use. When a physical disk drive or logical file fails, the most recent dump is read. Modifications to each file of the dump are made as compacted audit trail data is processed. The modified files are destaged to a spare disk drive.

Disk recovery/reconstruction

A system and method for providing transaction indivisibility in a transaction processing system through the use of commonly-accessible modules for monitoring and maintaining proper source message sequencing is provided. A source message is transmitted from the host processing unit upon recovery of a failure of the host processing unit, where the source message includes information destined for the database, and an identifying sequence number. The identifying sequence number is compared to a stored sequence number, where the stored sequence number is associated with an immediately preceding source message received prior to the failure of the host processing unit. A source message indivisibility failure is indicated where the identifying sequence number is not consecutive with respect to the stored sequence number, while the source message is added to a message execution queue if the identifying sequence number is consecutive with respect to the stored sequence number.

System for providing transaction indivisibility in a transaction

A system and method for assembling database restoration data according to transaction in a transaction processing system. Database restoration data is collated by chronologically storing updated database records in distinct storage banks partitioned according to its corresponding transaction. Resulting database record blocks from storage banks associated with completed database transactions are queued in the order that their corresponding transactions were completed. The queued database record blocks are transferred to storage media, whereby the queued database record blocks are arranged on the storage media according to transaction, and in the order that the active transactions were completed.

System and method for arranging database restoration data for efficient

Method and apparatus for providing backup memory storage for audit trail data within a computer system having a main memory storage, a non-volatile memory storage, and backup memory storage. The computer system executes a number of transaction programs which generate audit trail entries. As the audit trail entries are generated, a portion of the audit trail entries are stored in a portion of the main memory storage to create an audit trail. The audit trail entries are accumulated in the portion of the main memory storage until a request is received to write the portion of the main memory storage to a corresponding portion of the non-volatile memory. Subsequent portions of the audit trail entries are accumulated in subsequent portions of the main memory storage. An output transfer to the backup memory storage is made once a sufficient number of portions of the main memory storage have been written to corresponding portions of the non-volatile memory in order to maximize the transfer efficiency to the backup memory storage.

XPC backup for in-process audit

Method and apparatus for managing the allocation and release of memory space within a number of files shared by a number of hosts in a data processing system. A number of allocate and release tables are provided which are accessible by the number of hosts for managing the allocation and release of space within the number of files. Each one of the number of allocate and release tables corresponds to one of the number of files and provides a file location, file size, and indication to the number of hosts of which of the number of blocks within the file have been allocated and which of the number of blocks have been released. Any host may allocate one or more of the number of blocks to store messages created or received by the host by determining from the allocate and release tables which one or more of the number of blocks within one of the number of files are available. The host may then release the one or more of the number of blocks once the one or more of the number of blocks are no longer required to store the message. Once the one or more of the number of blocks are released, any of the number of hosts may allocate and release additional messages.

Shared file allocation and release

A system and method for organizing and managing recovery information on a per-transaction basis using distinct memory structures is provided. A transaction processing system includes one or more transaction request units for initiating data transactions with a database. A memory architecture includes storage modules to store transaction recovery information that is used in recovering from a transaction processing failure, and further includes transaction descriptor memory structures each of which correspond to a distinct transaction. The transaction descriptors allow access to the transaction recovery information to be isolated from other transaction recovery information. A control information field in each transaction descriptor stores a transaction identifier that identifies the distinct transaction to which it corresponds. The transaction descriptor also includes multiple information address fields, each of which includes a pointer to one of the storage modules that stores part of the transaction recovery information associated with the transaction identifier.

System and method for managing recovery information in a transaction

A system and method for balancing database transaction request distribution between various hosts in a multiprocessor transaction processing system is provided. The transaction processing system includes a database and multiple host processors each coupled to at least one database transaction request unit. Database transaction requests sent from the host processors are collectively entered into a commonly-accessible load balancing queue. Each database transaction request is accompanied by a source identifier that identifies the database transaction request unit which initiated the corresponding database transaction request. The queued database transaction requests from the load balancing queue are processed by currently-available host processors, regardless of which host processor initiated the database transaction request. A transaction request acknowledgment for each of the processed transaction requests is created and transferred to the database transaction request unit identified by their respective source identifiers.

Balanced input/output task management for use in multiprocessor

A transaction processing audit and recovery system is disclosed. After processing a transaction, an audit manager logs in audit records only changed blocks of data of a segment of a database. Upon failure of database backing storage, a prior copy of the database is reloaded to database backing storage that is available and a recovery manager reads the audit records and copies the changed blocks back to the database backing storage. An outboard file cache system is used in conjunction with the recovery manager to recover the database. The outboard file cache provides cache storage for segments of the database and writes non-contiguous blocks of one or more segments as directed in a single input/output request initiated from the recovery manager.

Method and apparatus for block-level auditing and database recovery in a

A multiprocessor data processing system is implemented with processors, each of which may request for a temporary time the exclusive lock on an object which is stored on a data base. To achieve this a lock processor synchronizes the locking and unlocking of the objects. The requesting processor directs the storage of the object from the data base into a selected high performance storage unit, where it has exclusive rights to modify or write into the object until the object is unlocked by the processor. An audit tape or disk records all modifications made to any object during a transaction. A non-volatile cache memory is inserted in the audit trail to store a before-look image of the object that resides in the high performance storage unit. Data compaction occurs by comparison of the before-look image with an after-look image to provide a difference image, which is supplied to an audit buffer that is coupled to the audit tape. The locking processor may unlock the secured object once the after-look image has been committed from either a stored version in the non-volatile cache or from a high performance main memory unit to the data base disk. The difference image and the after-look image associated with the difference image may then be stored in the non-volatile cache, and provided to the audit tape or disk and the data base disk in a sequence which is independent of the operating sequence of the requesting processor.

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Vadnais Heights, MN, United States of America

Michael J Hill