Abstract: Multiple corruptions and/or erasures in data storage or data communication systems are corrected. An encoder generates M of parity fields from N data channels. Each item of the generated parity fields is the result of simple exclusive-or operations on one item from one or more data fields and possibly one item from one or more of the other parity fields. A decoder can regenerate as many as M missing or corrupted fields of either data or parity using combinations of correct and/or previously corrected items as inputs using M independent parity equations to solve for and correct each missing or corrupted item in turn.

Abstract: A redundant array includes a plurality of disks, a bus coupling the disks, a receiving device, and a device to reconstruct a block stored in one of the disks. The device reconstructs the block with associated data and parity blocks from other disks. The device transmits the reconstructed block to the receiving device in response to the one of the disks being unavailable or degraded.

Abstract: A method and apparatus redundantly store data, in particular video data objects, in a distributed computer system having at least three processor systems, each processor system being connected in point to point two way channel interconnection with each other processor system. The data is stored in a redundant fashion both at the computer system level as well as the processor system level. Accordingly, the failure of a single processor does not adversely affect the integrity of the data. The computer system can also overlay a switching system connected in a ring fashion for providing a fault tolerance to the failure of a single connected processor system at the switch level. Accordingly, there results a fault tolerant data distribution system.

Abstract: A redundant array includes a plurality of disks, a bus coupling the disks, a receiving device, and a device to reconstruct a block stored in one of the disks. The device reconstructs the block with associated data and parity blocks from other disks. The device transmits the reconstructed block to the receiving device in response to the one of the disks being unavailable or degraded.

Abstract: A system has a node connected to a network, the node generating a separate session message for each of a plurality of users. The node places each of the separate session message in a slot in a single virtual circuit message, and transmits the virtual circuit message onto the network. A server is connected to the network, and the server receives the virtual circuit message, and the server identifies each of the separate session messages. The server then transmits each of the separate session message to a user having a session corresponding to each of the separate session messages.

Abstract: A local area network for interconnecting terminals and other users and data processing systems and other service providers over a communications link by means of interface units each of which may connect to several users or providers. The interface units communicate over the communications link by means of messages. When a user requires the use of a service, the interface unit establishes a virtual circuit between it and the interface unit connected to the service provider and a service session which allows the user and the service provider to communicate over the virtual circuit. If several users connected to the one interface unit as the first user require services provided by providers which connected to the same interface unit as the first provider, they communicate in sessions over the same virtual circuits. The session messages are accumulated into single virtual circuit messages that are acknowledged in unison by the receiving interface unit.

Abstract: A local area network for interconnecting terminals and other users and data processing systems and other service providers over a communications link. The users and providers connect to the communications link by means of interface units each of which may connect to several users or providers. The interface units communicate over the communications link by means of messages. When a user requires the use of a service, the interface unit establishes a virtual circuit between it and the interface unit connected to the service provider and a service session which allows the user and the service provider to communicate over the virtual circuit. If several users connected to the one interface unit as the first user require services provided by providers which connected to the same interface unit as the first provider, they communicate in sessions over the same virtual circuits. The session messages are accumulated into single virtual circuit messages that are acknowledged in unison by the receiving interface unit.

Abstract: Apparatus and methods, readily adapted to interface with a standard data transmission network having an unsecure transmission channel, e.g., "Ethernet," for the provision of secure transmission of data over the network channel in a manner which is essentially transparent to the standard network devices and users, thereof, are provided. Various encryption keys are generated and utilized within the system to disguise or encrypt information transferrred between network nodes. The encryption keys are made known only to those network devices which are permitted to handle information encrypted with the encryption keys.

Abstract: Apparatus and methods, readily adapted to interface with a standard data transmission network having an unsecure transmission channel, e.g., "Ethernet," for the provision of secure transmission of data over the network channel in a manner which is essentially transparent to the standard network devices and users thereof, are provided. Various encryption keys are generated and utilized within the system to disguise or encrypt information transferred between network nodes. The encryption keys are made known only to those network devices which are permitted to handle information encrypted with the encryption keys.

Abstract: A local area network for interconnecting terminals and other users and data processing systems and other service providers over a communications link. The users and providers connect to the communications link by means of interface units each of which may connect to several users or providers. The interface units communicate over the communications link by means of messages. When a user requires the use of a service, the interface unit establishes a virtual circuit between it and the interface unit connected to the service provider and a service session which allows the user and the service provider to communicate over the virtual circuit. If several users connected to the one interface unit as the first user require services provided by providers which connected to the same interface unit as the first provider, they communicate in sessions over the same virtual circuits. The session messages are accumulated into single virtual circuit messages that are acknowledged in unison by the receiving interface unit.