Abstract: Customer-service tasks are performed in a noninvasive manner by relying on automatic methods for (a) capturing the state of the operating domain and (b) automatically communicating this state as well as a description of the circumstances that lead to activation of the process to a remote service machine via an electronic network. Network-based customer-service for software support includes an automatic mechanism which initiates the product support process. This automatic mechanism may optionally be augmented by a manual mechanism for initiating the support process. The process captures the operating environment in sufficient detail so as to enable its re-creation in part or in whole on a separate machine. Archived data is transmitted to an off-site storage device, and when this data is received, notification is transmitted to customer-support personnel.

Abstract: A watch signature for a debug watch mechanism indicates one or more allowable events, which represent allowable accesses to a watched variable. The allowed accesses implicitly include thread information by limiting the allowable operations to a single thread that first performs an allowed operation. Any operations on the watched variable that are caused by a different thread, and any operations that are caused by the same thread other than those specified in the watch signature will create a notification that an unauthorized operation on the watched variable has occurred. The debug watch mechanism of the present invention thus does not notify the user for expected operations on the variable, but provides notification for other events that do not fall within the anticipated behavior of the computer program as specified by the watch signature.

Abstract: To change data in a database (DB) in such a manner that in case of a disturbance the database can be restored to an initial state, it is proposed to temporarily store the block numbers (BNO) of free memory blocks (BL*) in a nonvolatile semiconductor memory (NVM). In case of a disturbance, the free memory block (BL*) continues to be managed as a free memory block. In case of an undisturbed, successful change to the data, the memory block (BL) in which the old data were stored is deallocated. The invention is particularly suited for use in database systems for network elements of a digital communications network, particularly for crossconnects of an SDH network (SDH=Synchronous Digital Hierarchy).

Abstract: A method for creating a status report data file for a document job in a document system including a central database configured to create a status report data file for each document job received at the central database and a plurality of sub-systems coupled to the central database where each sub-system is configured to perform a specific document task pertaining to a document job. A status report for a document job is created in the central database upon the appearance of that job from any one of a plurality of sub-systems coupled to the central database.

Abstract: A data storage system wherein a host computer is coupled to a bank of disk drives through a system interface. The interface has a memory with a high address memory section and a low address memory section. A plurality of directors control data transfer between the host computer and the bank of disk drives as such data passes through the memory. A pair of high address busses electrically is connected to the high address memory and a pair of low address busses is electrically connected to the low address memory. Each one of the directors is electrically connected to one of the pair of high address busses and one of the pair of low address busses. A front-end portion of the directors is electrically connected to the host computer and a rear-end portion of the directors is electrically connected to the bank of disk drives.

Abstract: A method and apparatus for providing visualization of performance of a distributed network. The method provides a user interface allowing easy visualization of the performance together with methods and apparatus for determining the distance from a client to a server in the network, for determining a service provider domain, for determining network congestion level, for determining bottleneck throughput, for determining bottleneck location, for determining page retrieval time and for automatically restarting a page under predetermined conditions.

Abstract: An abnormality recovery system in a network comprising a plurality of station units connected by a ring-like data transmission line enabling circular transmission of communication data in digital form in a single direction. In the system, when it is determined that an abnormality occurs in a communication IC, a CPU performs switch control to switch a communication data route so as to bypass the communication IC and send communication data on a bypass from an optical receiver to an optical transmitter.

Abstract: A client-server computer system has one or more clients connected to one or more servers. During request/reply interactions, a client-side application sends a request for services (e.g., read a file, return some information, update a database record, process data, etc.) to the server. A server-side application request program processes the request, prepares a reply to the request, and returns the reply to the client-side application. The server runs a resource manager to log operations and data pages in a manner that enables application and database recovery. Among other tasks, the server's resource manager creates a stable log file that can be used to help recover the client-side application in the event of a system crash. To capture the client-server interaction, the server's resource manager records the reply in the log buffer and commits the reply record to the stable log before the reply is sent back to the client. This results in only one forced logging event for each request/reply exchange.

Abstract: An approach for recovering after premature termination of a plurality of transactions involves: A) selecting a previously unselected transaction from the plurality of transactions; B) processing the selected transaction by undoing the lesser of a predetermined number of changes made by the selected transaction and all changes made by the selected transaction; and C) repeating steps A) and B) until all of the plurality of transactions have been processed. Another aspect of the approach involves: A) selecting a previously unselected transaction from the plurality of transactions, wherein the selected transaction is the previously unselected transaction from the plurality of transactions that made the fewest number of changes in the database; B) processing the selected transaction by undoing one or more changes in the database made by the selected transaction; and C) repeating steps A) and B) until all transactions from the plurality of transactions have been processed.

Abstract: A system and method for determining which processor is to be the master processor in a symmetric multi-processor (SMP) environment. The determination is made by boot-level code, i.e. the software program which executes first in a processor after it is brought on-line. Each processor in the SMP system is brought on-line independently of the other processors in the system, and each processor in the system can uniquely identify itself. As a processor comes on-line, it checks to see if a master processor has already been designated. If not, the processor checks to see if another processor, with a higher priority identifier, has identified itself as a working processor. If so, the processor commits to being a slave processor. If not, the processor indicates that it is available to be the master processor. A further check is made to ensure that only one processor has indicated that it is available to become the master processor.

Abstract: In problem situations of a computer controlling a process, such as transmission of calls, it is very important to direct the maintenance operations in the correct manner at the correct places as rapidly as possible. In the fault data collection method according to the invention, fault data is collected selectively by using empirical data about what type of information is useful in solving problems. Data (P10A-40A) about each process family is searched for from the list of process families PL in the data area (DA) of the computer's operating system. By means of the first process (P10) of the process family, data is obtained about the other processes (P11-P14) of the family. The data structures (PA) of the processes (P10-P14) provide data about the memory resources reserved by the process, time supervision, etc. By comparing the content of the data structures (PA) to the empirical base values, data structures (PA) are copied to the storage area (SA) from the process that are to be examined in greater detail.

Abstract: An optical disc recording apparatus forms a plurality of tracks on the recording area of an erasable optical disc, divides each of the plurality of tracks into a plurality of packets, records data onto the packets and also has a rewriting means for rewriting data onto the plurality of packets if a recording error occurs during recording of the data. The optical disc recording apparatus allows efficient use of the recording area of an erasable optical disc.

Abstract: A system and method is disclosed for dynamically restoring communications within a network following an outage comprising a database containing the configuration of switching elements within the network and a plurality of instructions resident on a memory device for operating a control computer, wherein the plurality of instructions includes a code segment for receiving network parameters following the outage, a code segment for selecting restoration switching elements from the database based upon the network parameters, a code segment for generating connect and disconnect commands for the restoration switching elements, and a code segment for sending the connect and disconnect commands to the restoration switching elements, thereby restoring communications within the network.

Abstract: A method in a symmetric multi-processor computer system for increasing database transaction log performance by pipelining transaction log buffers. The method includes the steps of inserting a log record into a log buffer stored in a volatile memory of the computer system. Next, the log buffer is queued for eventual delivery to a persistent storage device. Then the log buffer is dequeued from the queue set in the previous step. Following this, a transfer of the contents of the log buffer to the persistent storage device is initiated. A wait is imposed on the process for the completion of the transfer of the contents of the log buffer to the persistent storage device in order to guarantee that the contents are safely stored in the persistent storage device in the original serial order as received.

Abstract: The present invention is a process-pair resource manager for use in a transaction processing system. The process-pair resource manager includes a concurrent aspect and a serial aspect. The concurrent aspect provides an object-like interface to a protected resource. An application program participating in a transaction accesses the protected resource by passing messages to the concurrent aspect. The concurrent aspect adds a description of each message as well as the result of processing each message to a transaction record. At the conclusion of a transaction, the concurrent aspect passes the transaction record to the serial aspect. The serial aspect then replays the transaction, using the transaction record. If the replay of the transaction is consistent with the transaction as recorded in the transaction record, the serial aspect sends a message to the concurrent aspect voting to commit the transaction. In turn, the concurrent aspect sends a message to the transaction manager forwarding the commit message.

Abstract: By checkpointing and restoring a user application process, that includes a volatile state and a persistent state, recovery of an application process from the checkpoint position is possible. Specifically, a volatile state is checkpointed in a checkpoint position. Next, the persistent state is monitored to detect a file operation following a checkpoint position that will modify the persistent state. Then, portions of the persistent state are checkpointed if a modification of the persistent state is about to be performed. Then, a recovery to the checkpoint position can be performed such that modifications to the persistent state since the checkpoint position are undone. This allows for resumption of the user application process from the checkpoint position.

Abstract: A method and system for the automatic data recovery for a duplex pair is provided. The preferred embodiment includes the discovery of lost data on the first subsystem. A copy of the lost data is automatically transferred from the second subsystem to the first subsystem. Then the copy of the lost data is automatically written into the first subsystem. The host processor and the operator is unaware data had been lost. The method and system of the present invention eliminates the need to terminate the job which triggered the discovery of the lost data. It also eliminates the need for any involvement of the operator in the data recovery process.

Abstract: A data processing system on an integrated circuit 42 with microprocessor 1 and peripheral devices 60-61 is provided with an emulation unit 50 which allows debugging and emulation of integrated circuit 42 when connected to an external test system 51. Microprocessor 1 has in instruction execution pipeline that has several execution phases which involve fetch/decode units 10a-c and functional execution units 12, 14, 16 and 18. The pipeline of microprocessor 1 is unprotected so that memory access latency to data memory 22 and register file 20 can be utilized by system program code which is stored in instruction memory 23. Emulation unit 50 provides means for emulating the unprotected pipeline of microprocessor 1 and for rapidly uploading and downloading memories 22-23. Microprocessor 1 is operable to halt in response to an emulation event with partially completed instructions still in the execution pipeline.

Abstract: A real time stream server using a disk device data restoration scheme, capable of shortening a restoration time by maximally utilizing the available stream resources, while providing the same service as in a case of normal operation, without setting any limitation on a new stream connection request during the restoration of lost data of a disabled disk device on a spare disk. The operations of the real time stream server is controlled by using normal streams for data transfer and restoration streams for data restoration, where as many stream resources as necessary are allocated to the normal streams first, and then at least a part of remaining stream resources are allocated to the restoration streams.

Abstract: A transaction log stored in a first memory is posted to one of two separate log areas, selectively, on a storage system having a plurality of storage media such as disk drives. Posting occurs to a "disk log" area when a page-full status of the first memory transaction log is detected. Alternatively, when a posting request occurs before a page-full status of the transaction log has been detected, then posting occurs immediately to a least busy disk of a "staging log" area. Posting occurs to the least busy disk of the "staging log" area by circumventing normal storage system data management and redundancy techniques such that data in the staging log area is not kept redundantly on the storage media. Rather redundancy is maintained by the fact that the transaction log remains with the first memory in addition to being copied to the staging log area. The staging log area includes reserved space on each of the plurality of storage media and is divided into logically separate portions on each of the storage media.

Abstract: The floating point data stored in an arbitrary cell is processed on the basis of a particular formula (S401), if an error due to column truncation occurs in a result of computation (S402) then the all the floating point data is converted to the fixed point data (S405), and the error occurring due to the floating point data is recovered automatically thereby improving the convenience of the recovery process.

Abstract: A system for performing transaction processing on user data maintains a transaction table. The transaction table holds the identities of structured storages that have been opened but not yet closed by each of the transactions that are accessing the structured storages. Each time that a stream holding user data is opened in a write mode, an internal copy of the stream is made. Changes are applied to the internal copy. At commit time, the following metadata operations are performed as a single atomic transaction. Each copy is renamed to have the name of the original stream. If no other transactions are accessing the stream, the original stream is deleted. However, if other transactions are accessing the stream, the original stream is renamed to have the name of the copy. The metadata transaction is implemented with write-ahead logging. Upon recovery from a system failure, any metadata transaction that was in progress at the time of the failure is undone.

Abstract: An apparatus for tracking processing of commands between command sources and sinks includes a command directory. The command directory receives a command from at least one command source, receives signals from command sinks, generates status information corresponding to the command based on the command and the received signals, and stores the status information. The status information indicates to which command sink the command is to be routed, whether the command sink has accepted the command, and whether the command sink has completed processing the command. The command directory includes a command buffer having a plurality of directory entries. The command buffer stores a command and associated status information in a directory entry. The command buffer also includes free buffer logic which monitors the status information in each directory entry. Based on this monitoring, the free buffer logic determines whether a directory entry has been disabled or whether command tracking errors exist.

Abstract: When an I/O request block is received from a file system, a number-of-system's-failures setting section stores the present number of failures in the I/O request block, and hands over the I/O request block to a software driver after taking a checkpoint. When the I/O request block is received from the software driver, a number-of-failures determining section determines whether or not the number of failures stored in the I/O request block coincides with the present number of failures. If they do not coincide, an I/O request error return section will return the I/O request block to the software driver without handing over it to a device driver and causes an I/O request completion processing section to reissue the I/O request block again.

Abstract: A database system facilitates quick failover. The database system includes a primary node, a standby node and a fast interconnect between the primary node and the standby node. The primary node includes a primary buffer pool which stores pages of the database information, and a log storage which receives a log of updates for the pages within the primary buffer pool. When a page is to be updated by a primary node, the primary node sends a copy of a before update image of the page to the standby node. When the primary log writes logs of updates to the log storage, the primary node also forwards the logs of updates to the standby node.

Abstract: A method for recovering from software fault in a fault tolerant computing system includes a system status recording step to record the system status at the occurrence of the above software fault when the above fault is judged to be a software fault by a fault identifying step, a software fault factor diagnosing step to diagnose the fault factor of the above software fault, a software fault recovery action determining step to determine a recovery action to the above fault factor of the above software fault, and a software fault recovery action executing step to execute the recovery action the above fault factor of the above software fault determined by the above software fault recovery action determining step after roll back.

Abstract: A fault tolerant message passing system includes a plurality of interconnected processors with storage and a watchdog process wherein the processors may undergo failure. A method restores a consistent system state using optimistic logging protocol with asynchronous recovery. Each process comprises a sequence of state intervals and includes checkpoints for saving in storage the state of the process sufficient to re-start execution of the process. Non-deterministic event messages are logged in storage by each process for replay after process re-start to reconstruct pre-failure state intervals. Transitive dependency tracking of messages and process states is performed to record the highest-index state interval of each process upon which a local process depends. A variable size dependency vector is attached to each outgoing message sent between processes. An integer K is assigned to each outgoing message as the upper bound on the vector size.

Abstract: The distributed memory type multiprocessor computing system according to the present invention includes a plurality of nodes which are coupled with each other so as to correspond to a tree construction by communicating switches. Each of nodes acquires checkpoints at a predetermined time for reexecuting the respective data processing from a previously acquired checkpoint when a fault occurred. Each of nodes starts the checkpoint acquisition in synchronous with all another nodes by prohibiting data transfer through the communication switch to another nodes and by making completion of data reception through the communication switch for keeping vacant state which no data exist in the communication switch.