Connected Corporation

Lumigent Technologies, Inc.

Emc Corporation

Digital Equipment Corporation

Cabletron Systems, Inc.

Lev Vaitzblit

David A Cane

Philip Speare

David Hirschman

Percy Tzelnic

Kadangode K Ramakrishnan

Dennis P Ting

Uresh K Vahalia

Wayne William Duso

John Forecast

Jonathan F Freidin

Murray S Mazer

Stephen Ng

Jonathan Jesse

Troy Runkel

Howard Marson

Kannan M Alagappan

Chad Council

Leonid Filatov

Jason Orendorff

Wayne Babich

Described is a database audit system used to monitor, and optionally alert on database activity, providing a complete record of access to data and database structure. The data audit system may also provide an audit trail of data accesses and changes to database schema and permissions. A database audit may be performed by collecting data from database transaction logs and traces, exporting the collected data into a repository, and analyzing the data in the repository to create data audit reports and to provide data audit browsing capabilities.

Process and system for auditing database activity

Most commercial database systems provide a recovery mechanism that is used to restore data integrity in the event of a hardware or software failure. Many of these systems restore the database from the most recent backup file by rolling forward all transactions from the most recent undamaged transaction log. The present invention discloses a novel system and method for recovering data from user or application errors. Embodiments of the present invention selectively target and undo only those transactions that caused data corruption. In this way, the present invention is able to recover fine-grained database objects such as a table or a row within a table. The present invention has the further advantage of minimizing the number of transactions that are lost after recovery.

System and method for transaction-selective rollback reconstruction of database objects

An information processing system providing archive/backup support with privacy assurances by encrypting data stored thereby. Data generated on a source system is encrypted, the key used thereby is separately encrypted, and both the encrypted data and encrypted key are transmitted to and maintained by a data repository system. The repository system receives only the encrypted data and key, while the source system retains the ability to recover the key and in turn, the data. The source system is therefore assured of privacy and integrity of the archived data by retaining access control yet is relieved of the physical management of the warehousing medium.

Secure File Archive through encryption key management

A method for the administration of a differential file backup system in a client-server system is disclosed in which the various component files that comprise a backup file are read from a first memory device of the file backup system to a second memory device and processed by the server. The server processes the various file components, or archive files in which the various file components reside, to reduce the number of access points across the first memory device to enhance the efficiency of the file retrieval, file reconstruction, and file restore operations of the backup file system.

Administration of a differential backup system in a client-server environment

A database of known commercial software programs ('Products') is maintained and employed as a template for selection of files for a backup operation. In particular, files which are part of known Products may be excluded during backup operations. Records indicating rules about which files within Product directories are included and excluded from the backup operation are also maintained in the database. Product directories may be determined from a registry or the hard disk may be scanned and directories checked against a list of known Product default directories. If the newly found directory does not match an entry in the list of default directories, then file list codes in the database are checked against the files in the directory to determine whether known Product files are present in the directory. Two types of exclusion commands are employed to identify files for exclusion from the backup operation by exploiting file creation and modification dates. The first command type establishes a baseline date by looking at the last modification date of the file. The second command type instructs the backup program to exclude selected files in selected subdirectories in accordance with predetermined criteria.

Database/template driven file selection for backup programs

File comparison employs a single function F to calculate a digital signature from data in a sliding window. The digital signature is both incrementally computable and position sensitive. In particular, F is computable without reprocessing each byte in the array when the window is advanced and facilitates detection of such changes as transposed bytes of data. The function F is defined by two qualities. First, for F(A+B), where A is an array, F(A+B)=F(A)+F(B). Second, given a concatenation operator '!' such that '0!A' indicates an array A with 0 inserted before A, the function F has the property that there is a function G such that F(0!A)=G(F(A'0)). Both polynomials and cyclic redundancy checks ('CRC') may be used as that class of function.

File comparison for data backup and file synchronization

Method and apparatus for avoiding receive livelock and transmit starvation, and for minimizing packet loss and latency in a communication network station. The invention uses a combination of processing threads, polling and, in a preferred embodiment, a judicious use of interrupts, to allocate the use of processing resources fairly among competing functions. Real time processing threads are structured to execute for a preselected maximum time interval, based on numbers of units processed by each thread, and then to yield control to a thread scheduler, which selects and invokes a new thread for execution. Work to be done in the various threads is determined either by polling or by an interrupt system, and then posted to the threads for execution. If interrupts are used, interrupt service routines perform only the minimal processing needed to recognize an interrupt, other interrupt servicing functions being deferred for execution in a processing thread. The thread scheduler operates on a round-robin basis and also selects from at least one general purpose processing thread for functions that are less time critical, the general purpose thread being structured to operate for a selected minimum time, if needed, in a non-preemptable mode, and thereafter in a preemptable mode.

Scheduling mechanism using predetermined limited execution time

A video file server includes an integrated cached disk array storage subsystem and a plurality of stream server computers linking the cached disk storage system to the data network for the transfer of video data streams. The video file server further includes a controller server for applying an admission control policy to client requests and assigning stream servers to service the client requests. The stream servers include a real-time scheduler for scheduling isochronous tasks, and supports at least one industry standard network file access protocol and one file access protocol for continuous media file access. The cached disk storage subsystem is responsive to video prefetch commands, and the data specified for a prefetch command for a process are retained in an allocated portion of the cache memory from the time that the cached disk storage subsystem has responded to the prefetch command to the time that the cached disk storage subsystem responds to a fetch command specifying the data for the process. The time between prefetching and fetching is selected based on available disk and cache resources. The video file server provides video-on-demand service by maintaining and dynamically allocating sliding windows of video data in the random access memories of the stream server computers.

Video file server using an integrated cached disk array and stream

A information processing system providing archive/backup support with privacy assurances by encrypting data stored thereby. Data generated on a source system is encrypted, the key used thereby is separately encrypted, and both the encrypted data and encrypted key are transmitted to and maintained by a data repository system. The repository system receives only the encrypted data and key, while the source system retains the ability to recover the key and in turn, the data. The source system is therefore assured of privacy and integrity of the archived data by retaining access control yet is relieved of the physical management of the warehousing medium.

Secure file archive through encryption key management

A scheduler with admissions control in a continuous media file server is presented. The scheduler supports multiple classes of tasks with diverse performance requirements. The scheduler is based on a combination of rate-monotonic and weighted round-robin scheduling schemes. Scheduling is accomplished in a hierarchical manner. Isochronous tasks have the highest priority and are scheduled first followed by real-time and general-purpose tasks. Isochronous tasks run periodically and are invoked by a timer interrupt set for each task. After scheduling the isochronous tasks, the scheduler alternates between the real-time tasks and the general-purpose tasks using a weighted round-robin scheme.

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Concord, MA, United States of America

Lev Vaitzblit