Mangosoft Corporation

Digital Equipment Corporation

Compaq Computer Corporation, Inc.

Mangosoft Intellectual Property, Inc.

Scott H Davis

Daniel J Dietterich

Steven J Frank

John B Carter

David William Thiel

William L Goleman

Robert S Phillips

David G Porter

Hsin H Lee

William Abraham

Robert G Bean

Scott Nyman

James A Zahrobsky

Phillip John Romine

John Woods

Gerard R Plouffe

Thomas G Hansen

Paul D Asselin

A multi-user file storage service and system enable each user of a pre-subscribed user group to communicate with a remote file server node via a wide area network and to access the files of the file group via the respective client node. More than one user of the pre-subscribed user group is permitted to access the file group at the remote file server node simultaneously. Integrity of the files at the remote file server node are maintained by controlling each access to each file at the remote file server node so that each access to files at the remote file server is performed, if at all, on a respective portion of each file as most recently updated at the remote file server node. Additionally, an encrypted key is transferred from the file server node to a particular client node via a secure channel. The encrypted key uses an encryption function and a decryption function not known locally at the remote file server. Furthermore, both privileged access control rights and file sharing mode access control to a particular file of the group of files are delegated to one or more distributed nodes other than the remote file server node which provides the data.

Internet-based shared file service with native PC client access and semantics and distributed access control

A multi-user file storage service and system enables each user of a user group to operate an arbitrary client node at an arbitrary geographic location to communicate with a remote file server node via a wide area network. More than one user of the user group is permitted to access the file group at the remote file server node simultaneously, but the integrity of the files is maintained by controlling access so that each access to one of the files at the remote file server is performed, if at all, on a respective portion of that file as most recently updated at the remote file server node.

Internet-based shared file service with native PC client access and semantics

A method and system are provided for optimizing the local caching of one or more data components available from a server node. Each of plural nodes connected to a local area network is provided with a locally physically present cache. Each of the caches of at least some of the plurality of nodes are linked together into a single virtual cache. A particular one of the nodes is designated as a repository node for persistently storing a particular data component and for providing a copy of the particular data component to other referencing nodes of the plurality of nodes which lack, but which desire to access, the particular data component. Designation of the particular node as the repository node is unchanged solely by providing a copy of the particular data component to one of the referencing nodes that desires to access the particular data component. The repository function of a node for a particular data component is relatively static. For instance, assume that a first referencing node obtains from the repository node a copy of the particular data component and performs a group of one or more access operations on the copy of the data component. If another referencing node lacks a copy of, but desires to access, the particular data component, a copy of the particular data component is provided from the repository node to the other referencing node. One of the nodes may be designated as a monitor node for the particular data component. The monitor node responds to requests by each referencing node to identify the repository node of the particular data component by providing the identity of the particular node which serves as the repository node for the particular data component.

Distributed virtual web cache implemented entirely in software

In a network of computer nodes, a directory service provides both the physical location of directory information around the network and the directory information itself in a single data structure. This single data structure is distributed throughout the network, and continuously redistributed, so as to create a directory service that is both more flexible, and more robust, than prior art directory services.

Dynamic directory service

Disclosed is a method and apparatus for accessing data in a computer system after a failed data operation in which I/O process state information is unknown. The failed data operation may cause data inconsistency among multiple devices associated with a shadow set for storing data. The disclosed system includes techniques for allowing continued data accesses while simultaneously re-establishing data consistency among members of the shadow set.

Method and apparatus for accessing data in a shadow set after a failed data operation

Distributed shared memory systems and processes that can connect into each node of a computer network to encapsulate the memory management operations of the connected nodes and to provide thereby an abstraction of a shared virtual memory that can span across each node of the network and that optionally spans across each memory device connected to the computer network. Accordingly, each node on the network having the distributed shared memory system of the invention can access the shared memory.

Shared memory computer networks

A shared client-side Web cache is provided by implementing a file system shared between nodes. Each browser application stores cached data in files stored in a globally addressable data store. Since the file system is a shared one, the client-side Web caches are also shared.

Shared client-side web caching using globally addressable memory

A computer system employs a globally addressable storage environment that allows a plurality of networked computers to access data by addressing even when the data is stored on a persistent storage device such as a computer hard disk and other traditionally non-addressable data storage devices. The computers can be located on a single computer network or on a plurality of interconnected computer networks such as two local area networks (LANs) coupled by a wide area network (WAN). The globally addressable storage environment allows data to be accessed and shared by and among the various computers on the plurality of networks.

Remote access and geographically distributed computers in a globally

In a network of computer nodes, a structured storage system interfaces to a globally addressable memory system that provides persistent storage of data. The globally addressable memory system may be a distributed shared memory (DSM) system. A control program resident on each network node can direct the memory system to map file and directory data into the shared memory space. The memory system can include functionality to share data, coherently replicate data, and create log-based transaction data to allow for recovery. In one embodiment, the memory system provides memory device services to the data control program. These services can include read, write, allocate, flush, or any other similar or additional service suitable for providing low level control of a memory storage device. The data control program employs these memory system services to allocate and access portions of the shared memory space for creating and manipulating a structured store of data such as a file system, a database system, or a Web page system for storing, retrieving, and delivering objects such as files, database records or information, and Web pages.

Structured data storage using globally addressable memory

A network of computer node interface to globally addressable memory system that provides persistent storage of data exchange periodic connectivity information. The exchanged connectivity information provides information regarding node failure to other nodes in the system, and the surviving nodes use the information to determine which node, if any, has ceased functioning. Various processes are used to recover the portion of the global address space for which the failed node was responsible, including RAM directory, disk directory, or file system information. Additionally, nodes may be subdivided into groups and connectivity information is exchanged between nodes belonging to a group. Each group then exchanges group-wise connectivity information and failures may be recovered.

System and method for providing highly available data storage using

The present invention is a method of writing data to a storage system using a redundant array of independent/inexpensive disks ('RAID') organization that eliminates the write hole problem of regenerating undetected corrupt data. The invention also overcomes the need for system overhead to synchronize data writes to logical block numbers that map to the same parity block. A log is constructed and used for storing information relating to requested updates or write operations to the data blocks in the multiple disk array. A separate entry is made in the log for each parity block that must be updated as a result of the write operation. Each log entry contains the addresses of the logical block numbers to which data must be written for that operation. After the new data is written to data blocks in the RAID array, a background scrubber operation sequentially reads the next available entry in the log and performs a parity calculation to determine the parity resulting from the write operation. The new parity information is written to the corresponding parity block and the log entry is deleted by the scrubber operation to indicate that the parity block corresponds to the data it represents. In addition, if a system failure occurs during a data write or after the data write but before the associated parity block is written, the original data can be accurately reconstructed using the remaining data blocks and the original parity information that remains in the parity block.

System for storing pending parity update log entries, calculating new

A log for managing data in a shadow set of storage media includes a system for maintaining a log of address information associated with at least one write command received from one of a plurality of data processing devices. The system for maintaining a log of address information includes a device for receiving a write command from a data processing device, a device which writes data associated with the write command in a section of one of the storage media, and a device which writes address information in a log indicative of the location of that section. A device is provided which then implements a management operation on data stored on one of the storage media in accordance with the address information stored in the log.

Log for selective management of specific address in a shadow storage

A method and apparatus for transferring data between two storage media, and is used in an illustrative embodiment to transfer data between two storage media in a shadow set, the storage media being accessible to one or more host processors. The method of the preferred embodiment includes the steps of: A. receiving a command from one of the host processors, the command specifying data to be transferred from a first storage medium to a second storage medium; B. transferring the data specified in the command received from the host from the first storage medium to the second storage medium in a series of subtransfers, each of the subtransfers transferring a portion of the data; and C. processing one or more I/O requests to the shadow set received from one or more host processors by, for each received I/O request: a. implementing the I/O request if the I/O request does not involve a section of the shadow set currently involved in one of the subtransfers; and b. stalling the I/O request if the I/O request involves a section of said shadow set currently involved in one of the subtransfers, and implementing the I/O request when the subtransfer has completed.

Transferring data in a digital data processing system

A digital data management system for managing a shadow set of storage media includes a plurality of storage media each accessible by at least one data processing device for I/O operations. Successive comparisons are carried out between data stored in corresponding locations in the storage media while maintaining access to the storage media for I/O operations. When inconsistency between data in corresponding locations is detected, a management operation is performed on at least one of the shadow set storage media. The management operation includes interrupting I/O operations to at least the storage medium on which the operation is performed, modifying data on one of the shadow set storage media to correct the inconsistency, and resuming availability of the storage media for I/O operations.

Digital data management system for maintaining consistency of data in a

A system and method for transferring data from a first storage medium to a second storage medium, each of the storage media being divided into corresponding data blocks, the method comprising steps of: (a) reading data stored in a first data block in the first storage medium, the first data block initially constituting a current data block; (b) comparing data read in the current data block to data stored in a corresponding data block in the second storage medium; (c) if the data compared in step b are identical, reading data stored in a different data block in the first storage medium, the different data block becoming the current data block, and returning to step b; (d) modifying the data stored in one of the storage media such that the data in the current data block is identical to the corresponding data in the second storage medium; and (e) rereading the data in the current data block and returning to step b.

Growing community of inventors

Groton, MA, United States of America

Scott H Davis