Abstract: A method of encoding data and commands as N-bit words includes using a first portion of the word to identify whether the word carries data or a command. In the case of a command, the command is in a second portion of the word. In the case of data, a part of the data is contained in the second portion of the word, while the remaining part of the data is encoded in the first portion of the word.

Abstract: A DC power distribution system can be configured to utilize a variable number of AC power distribution units. Installation of a converter unit in place of a PDU and resetting of associated switches permits inexpensive and rapid reconfiguration of the system without interrupting power supply to current receiving units. Techniques such as mechanical keying and sense switches minimize the possibility of human error in the reconfiguring operation.

Abstract: A method and apparatus for transporting IDL-defined data structures to and from a format convenient for transport between two computers are disclosed. The data structures is originally described in a string. The string description is converted to a different format containing additional information about the alignment and size of the data structure. An application in the sending computer removes the alignment from the data structure and stores the data structure in a buffer. The data structure is stored in the output buffer in a predetermined format that is based upon the type of the data structure. The buffer is then transmitted to a data file or to the memory of the receiving computer. The receiving computer extracts the data structure from the buffer based upon the predetermined format. The data structure is realigned and stored in the memory of the second computer.

Abstract: An apparatus and method for getting descriptors to data and passing the descriptors among data sources and sinks, thereby avoiding copying the data among the data sources and sinks. The data source/sink which consumes the data actual initiates the copying of the actual data itself, using global pointers to the data in the descriptors.

Abstract: A highly reliable computer memory storage system that is divided into subsystems, each of which is provided in triplicate: a primary subsystem, a backup subsystem and a spare subsystem. Upon detection of a non-recoverable failure in a primary subsystem, the backup subsystem substantially immediately assumes the tasks of the primary subsystem while the spare subsystem is integrated into the operation of the computer memory storage system. The triple replication of all subsystems and mechanisms for detecting failures in at least the primary and secondary subsystems provides an overall memory system which is highly reliable and substantially never requires servicing. In an alternative embodiment, three subsystems can share a load equally, for example a cooling or power supply load requirement.

Abstract: A method and apparatus are disclosed for improving public key encryption and decryption schemes that employ a composite number formed from three or more distinct primes. The encryption or decryption tasks may be broken down into sub-tasks to obtain encrypted or decrypted sub-parts that are then combined using a form of the Chinese Remainder Theorem to obtain the encrypted or decrypted value. A parallel encryption/decryption architecture is disclosed to take advantage of the inventive method.

Abstract: A fault-tolerant computer system employing multiple CPUs executing the same instruction stream under independent clock cycle timing. The CPUs deterministically execute the instructions internally until input or output operations require access to memory or devices which are not synchronous with the local CPU clock. The CPUs are forced to take the same number of CPU clock cycles to complete the I/O operations. When the I/O operation is complete the internal processing of the instruction stream continues in a manner which is clock aligned in each of the multiple CPUs but which may be separate in real time due to oscillator drift. Accumulated drift is periodically removed by a timed interrupt which forces resynchronization of the CPUs in real time.

Abstract: A method and apparatus for translating source code written in one computer language to source code written in another language wherein translated static fragments are generated in the face of textual inconsistencies. Exactly one target language definition of each source language static fragment is generated and the differences are encapsulated in new parameters.

Abstract: A computing system includes a pair of central processor units structured to operate in substantial synchronism to each execute the same instruction at substantially the same moment in time of identical instruction streams to achieve a logical central processor unit with fail-functional operation. One of the central processor units includes a pair of processors that execute, instruction by instruction, the instruction stream with checking for fail-fast operation. The other central processor unit includes only a single processor element. The system achieves a low cost fail-functional architecture.

Abstract: A bracket (28) secures a header (12) to a PWB (22) and includes a face plate (32) having an opening (34) sized to receive a portion (33) of the header. The face plate, and header therewith, is secured to the PWB by mounting tabs (44) secured to and extending from the face plate. Each mounting tab is relatively thin and has its narrow-width peripheral edge portion (56) adjacent to the surface (24) of the PWB. The edge portion has an opening (54) sized to accept a rivet (62) to affix the bracket to the PWB. The edge portion contacts a ground pad (66) on the PWB to provide grounding of the PWB through the bracket. The bracket includes centering tabs (48) which engage the edges (62) of the chassis openings (10) to properly position the header in the opening.

Abstract: A local computer system has a local database, application programs that modify the local database, and a transaction manager that stores audit records in a local audit trail reflecting those application program modifications to the local database. Each audit record has an associated audit trail position. A remotely located computer system has a backup database. A remote data duplication facility (RDF) is partially located in the local computer system and partially in the remote computer for maintaining virtual synchronization of the backup database with the local database. The RDF includes an extractor process executed by said local computer system, and a receiver process and a plurality of updater processes executed by the remote computer system. The extractor process extracts audit records from the local audit trail and transmits those records to the receiver process.

Abstract: A cache is distributed among processors in a multiple processor system with no shared memory to maintain the cached data. Each processor maintains a cache which identifies the opened files being cached, the blocks of each file which are cached and the state of caching for each file. The state of each opened file is one of "no-caching", "read-caching" and "read/write caching". So long as only one processor opens a file, and opens it for read/write access, that processor is allowed to do read/write caching on the file. When a processor opens a file for read access, that processor is allowed to do read caching, unless another processor has the file open for read/write access. After the last processor having read/write access to a file closes the file, the disk system upgrades the cache state for the file.

Abstract: A supply voltage monitor for providing an indication of a supply voltage level considered safe for electronic circuit operation includes a supervisory or guard circuit that blocks the output of the monitor in favor of a secondary output for those periods of time when the monitor is considered to not be able of providing a valid reflection of supply voltage status.

Abstract: An improved recovery method utilizes sequence numbers to order log records and reduce the excess compensating actions due to a failure during recovery. Next undo records are written to the log after a preset number of compensating actions which include the sequence number of the record currently being scanned. After a failure, all records between the next undo record and the record having the sequence number included in the next undo record are ignored during when the log is scanned backwards.

Abstract: A method and apparatus for maintaining network connections across a voluntary takeover involving the use of dual processors in an protocol process node running a protocol process application as an intermediary to server and client applications. The protocol process node's primary processor checkpoints data to a backup processor. The data relates to the creation of a network connection between the server and client. Using the checkpointed data, the backup processor can assume the responsibilities of the primary processor in the event of a voluntary takeover of the primary processor.

Abstract: A computing system develops time/date values by using a free-running counter to measure and accumulate increments of time. The increments of time are converted from the resolution of the free-running counter to that used for the time and date values by dividing by a conversion variable and then used to update the time/date value. The accuracy of the time/date value is monitored by periodically comparing the rate of the free-running counter to the rate of a more accurate, external clock. The ratio of these two rates is used to adjust the conversion variable. The conversion variable reflects any differences between (1) the rate of change of the increments of time used for developing the time/data value and (2) the external clock. Its use here, therefore, will operate to either slow down or speed up the rate of change of the time/date value so that it more closely tracks the external clock.

Abstract: A system and method for optimizing a database query is herein disclosed. The system consists of a search engine and a database implementor that determines an optimal plan for executing a SQL query. The SQL query is represented as a query tree consisting of a number of nested expressions. The search engine generates a number of plans from which an optimal plan is selected. Plans are generated through the application of a set of rules consisting of implementation and transformation rules. Implementation rules are used to obtain plans. Transformation rules are used to determine equivalent expressions. A plan for the query tree entails finding plans for each expression within the tree where each plan is generated in accordance with a prescribed set of rules. The database implementor selects the set of rules such that more promising plans are generated rather than generating all possible plans.

Abstract: A system and method for optimizing a database query with improved performance enhancements is herein disclosed. The database query consists of one or more logical expressions. Through the repeated application of one or more rules, the logical expressions are transformed into physical expressions and in some cases, execution plans that implement the database query. Each expression has associated with it a set of group attributes that specifies its characteristic inputs and outputs and a cost that estimates the computational expense for executing the expression. The group attributes are used to categorize similar expressions into groups that are stored in a search data structure. They are also used to track duplicate expressions. The cost associated with an expression is used to guide the search process to consider those expressions that will produce low cost plans.

Abstract: An system and method for creating applications having look and feel providing dynamically extensible languages for describing application look and feel. Engines are provided for executing programs written in the languages, and methods for extending the languages by creating new language operators are also provided. Methods for joining modules of functionality to new operators allow display of, and interaction with, functionality to be expressed in the extensible languages. The engines and languages permit language operators and functionality modules to be dynamically loaded.

Abstract: A method and system for preparing a suite of test scripts for testing a proposed network management application. The proposed network management application, termed a subsystem control facility (SCF), is first defined as a set of requirements with the aid of a developmental tool incorporating a subsystem knowledgebase and a test generation knowledgebase. The subsystem knowledgebase contains the rules governing the operation of a given network and a library of permitted commands, objects, attributes, modifiers and other data. The test generation knowledgebase includes information relating to those commands and object specific to the proposed subsystem control facility set of requirements. A user interface coupled to the knowledgebases permits the selection of types of tests and specific commands and objects to be tested.