Lucent Technologies Inc.

At&t Ipm Corp.

Kenneth Lane Thompson

James David Johnston

Schuyler Reynier Quackenbush

Nuggehally Sampath Jayant

Sean Matthew Dorward

Gerard Johan Holzmann

Robert C Pike

Philip Steven Winterbottom

A technique for testing event driven software. In accordance with the technique, the source code of the event driven software is directly converted to an automation based model useful in verifying that the program code complies with the desired properties defined by the user. More particularly, the event driven system program code is translated into a target language for a particular model checker. Such a translation results in a model which contains statements directed at whether execution of the program code will affect the behavior of the event driven system. Thus, this model extraction process can be used as input to a logic model checker for determining whether event driven system complies with the desired correctness properties specified by the user. Advantageously, the model extraction process and application of the model checker occurs in a direct and dynamic fashion from the subject event driven system program code without the need for user intervention.

Method and apparatus for testing event driven software

An independent transport layer is used as an error correction mechanism in a method employing perceptual audio coding. The transport layer is characterized by the addition of information, via a transport header, to each of a succession of blocks of encoded program material which is independent of the information within its respective block of encoded program material. The transport header comprises information on the structure of the block. Thus, the transport header is easily separated from the digital representation of the program material and is independent of the content of the digital representation thereby providing for changing of the content of the digital representation without changing the transport layer.

Device and method for efficient utilization of allocated transmission

An operating system which is particularly adapted to heterogenous distributed systems. Entities available to a process running in the operating system are provided by services. Each service models its entity as a set of files. The entity is controlled by performing operations on the set of files provided by the entity. Services other than those provided by the operating system all employ the same protocol specifying operations on files. The only requirement placed on a service by the operating system is that it be able to accept and respond to messages employing the protocol. The files are named, and the operating system provides a plurality of name spaces, relates each process to one of the name spaces, and permits any process to modify its name space or to create a new name space. Services are disclosed which provide each process using the service with its own set of the service's files and which provide files belonging to one process's namespace to another process executing on a different processor.

Distributed computing system

A file system which has component file systems including a primary file system which is react/write and a number of dump file systems which are read only. Each dump file system is created from the primary file system by means of a dump operation and conserves the state of the primary file system at the time the dump operation was performed. Component file systems share read only storage elements with older component file systems. The file system is implemented on a system including a file server, a magnetic disk mass storage device, and an optical write once-read many (WORM) disk. The magnetic disk mass storage device contains the read/write storage elements of the primary file system and encached read only storage elements from the WORM disk. Space is reserved on the unwritten portion of the WORM disk for the read-write storage elements of the primary file system. Techniques for performing file operations including opening, reading, writing, creating, and deleting files are disclosed, as well as techniques for performing the operations of dumping and restoring the primary file system.

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Watchung, NJ, United States of America

Kenneth Lane Thompson