Prime Computer Inc.

Richard G Bahr

Thomas C Hogan

Russell L Moore

Helen S Raizen

Paul Cohen

Alan G Nemeth

Daryl F Kinney

Thomas F Fox

A bit selection and routing apparatus and method selects m data signals from among its n available data inputs and groups those m signals on its output lines. The apparatus employs a two-dimensional array of signal selection elements which are multiplexing elements. The circuitry is implemented in NMOS technology using pass transistors. The apparatus can be placed in a data flow path and can pass data either unaltered, in a selection mode, in a shift mode, and in a partial data pass mode wherein an upper portion of the input word is set to a predetermined value. The selection elements are connected to route the selected input signals to selected output lines in a predetermined order.

Bit selection and routing apparatus and method

A system for transferring solicited message packets between data processors coupled on a serial communications path. A solicitor processor allocates a portion of its memory for storage of solicited message packets which might be solicited and received from at least one other data processor. The solicitor data processor defines a sequence of operations to be performed on any such received solicited message packets at that processor. The solicitor processor also transfers a solicited message parameter signal to the solicitee data processor where that signal is representative of a predetermined header portion for solicited data packets which might be generated by the solicitee data processor and transferred to the solicitor data processor. The header portion of a solicited message packet relates one or more of the sequences of operations which are to be associated with that packet. At least one of the other data processors receives any solicited message parameter signal addressed to that solicitee data processor. The solicitee processor is responsive to a received message parameter signal to generate a solicited message packet (with a header portion, as defined by the solicited message parameter signal) for transfer to the solicitor processor. The solicitor processor receives any such transmitted solicited message packet and stores that packet in the allocated portion of memory.

Solicited message packet transfer system

A ring communications network which is automatically reconfigured based on the detection of system defects.

Reconfigurable ring communications network

A ring communications system having a double ring format where the integrity of both rings is continuously checked, and where repair of the network is automatically accomplished upon the detection of the return to operation of a defective ring.

Self-repairing ring communications network

A communications network including a plurality of terminals coupled together to provide a unidirectional communications ring. Each of the terminals is coupled in series along the ring. Each terminal is adapted to transmit (at an associated data rate) a digital signal to the next downstream terminal on the ring. Each terminal is adapted to receive a digital signal at the data rate associated with the next upstream terminal. The received digital signal is applied to a phase locked loop characterized by a hold time which exceeds its lock time. The phase locked loop extracts a local timing signal for re-clocking the received digital signal. The transmission time of N bits is less than the hold time of the phase locked loop. Each terminal monitors the re-clocked signal to identify when same valued consecutive bits are received for a period less than the phase locked loop hold time, and upon such detection to cause that terminal to generate at least one transition.

Self initializing phase locked loop ring communications system

A communications network including a plurality of terminals coupled together to provide a unidirectional communications ring. Each of the terminals is adapted to transmit (at an associated fixed data rate) a digital signal to the next downstream terminal on the ring. Each terminal is adapted to receive a digital signal at the data rate associated with the next upstream terminal. In each local terminal, there is a detector for detecting the received synchronization packets and associated data packets are generated for transmission to the next downstream terminal on the ring at a predetermined fixed data rate associated with the local terminal. The data of each transmitted data packet matches bit for bit the data of the corresponding received data packet. The number of bits in the transmit synchronization packet differs from the number of bits in the associated received synchronization packet in a manner so that the data rate for the composite packet formed by the transmitted data packet and associated synchronization data packet corresponds to the transmit data rate for the terminal. The difference varies between predetermined minimum and maximum limits, and may be zero for two terminals having substantially the same transient bit rate.

Ring communications system

A token-passing, ring-based data communications network provides a distributive method and apparatus for detecting and regenerating a lost token. The method includes, after detection of the loss of the token, transmitting at a detecting node a data packet not including a token, the data packet uniquely identifying the transmitting node as the data source. Simultaneously, the transmitting node, after transmitting the tokenless data packet, strips all incoming data from the network. If the transmitted packet is successfully received by the transmitting node, a new token is generated by the node. If the packet is not received, the node defers to an arbitration method which includes delaying a next data packet transmission for a probabilistically determined period of time. The mean time upon which the probabilistic approach is based increases with each unsuccessful data packet transmission attempt.

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Framingham, MA, United States of America

Richard G Bahr