Abstract: An improved group-based routing update technique allows limited per neighbor customization of routing update messages generated by an interdomain router for its neighboring peer routers within autonomous systems of a computer network. The technique may be employed when the neighboring peer routers share identical routing policies, but the routing update messages differ only in certain attributes with known locations and lengths. Appropriate values of the location and length attributes for each neighboring router are calculated and stored during a replication stage of the improved technique. Before each message is transmitted, the proper location and length attributes of the message are updated with the stored values for the respective neighbor.

Abstract: A vivid color correction technique eliminates artifacts from a predetermined tonal area of a halftone image to thereby improve the color vividness of that image. According to this technique, pixel tonal values associated with input colors are initially examined to determine a maximum color value. After error diffusion halftoning, the resulting binary pixel values are collectively processed to generate inter-color information for comparison with a selected harmonic color cluster. If the inter-color information specifies a color that does not match one of the colors of the selected harmonic cluster, the inter-color information is "corrected" to reflect an acceptable output color.

Abstract: A helical type tape recording and reproducing system records blocks of user data-of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. The system format includes helical tracks in which user data blocks are recorded and longitudinal tracks for storing address information relating to the physical layout of the tape and to the content of the recording in the helical area. The system includes a partition access bookkeeping feature that stores information relating to locations at which searching or recording has been performed during a current load of a tape in the system, which is useful in accomplishing efficient searching for user data recorded on the tape. The present invention is directed to system search capabilities, including longitudinal searching along the tape and searching in the helical recording area of the tape.

Abstract: Adaptive preprocessing is performed on the three primary color signals generated during the scanning of a color image in order to enhance the perceived saturation of the dominant primary color. This preprocessing is performed by removing a small increment from the least intense primary color and adding the same increment to the most intense primary color. In this manner the overall brightness of the pixel is preserved, but the perceived saturation is increased. The increment that is effectively transferred from the least intense primary color value to the most intense primary color value is based on the relations of the three primary color values to each other in order to avoid visible color artifacts.

Abstract: A helical type tape recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. Each physical block is recorded as a double frame on a set of successive helical tracks, preferably 32 tracks. Each double frame has system format data interleaved with the user data. The present invention is directed to system format data that includes a sequence number for each physical block and enables the system to determine during reproducing if any physical block has been lost. The system also includes a partition access bookkeeping feature that stores information relating to locations at which searching or recording has been performed during a current load of a tape in the system, which is useful in accomplishing efficient searching for user data recorded on the tape.

Abstract: A novel mechanism prevents interleaving of packet cells from different source nodes on the same multicast port group at switches of a multicast virtual circuit in a cell-switched network: however, different cells bound for different multicast port groups may be interleaved. The mechanism comprises specific routing information that is stored in each multicast group port entry of a forwarding table located within each switch of the multicast virtual circuit. The forwarding table also stores information relating to each multicast port group including a virtual circuit value for each port of the multicast group. The specific routing information is provided for each multicast port group entry to notify the switch when data traffic for a particular packet is pending through a port of the multicast group and when that data traffic ceases, i.e., when the "end-of-packet" is reached. This ensures that the packets may be correctly reassembled at the destination nodes.

Abstract: A pipelined Viterbi decoder includes a plurality of circuit stages and a synchronous clocking arrangement for controlling the operations of the circuits within each stage. Specifically, an input stage converts multi-level input signals into streams of even and odd digital data samples. A parallel-precomputation stage adaptively establishes a threshold range for each sample, while a sequence detection stage designates one of the multiple levels for that sample and then determines the validity of that designation. Validity is determined in accordance with the sequence property of alternate samples in multi-level coding. Violations of the sequence property are corrected by a sequence correction stage so that valid, coded data and clock signals are provided at the outputs of the decoder.

Abstract: A digital servo track pattern for a magnetic medium which can be recorded and reproduced by a recording and reproducing system. The servo track pattern has a plurality of digital mark patterns recorded thereon, each of said digital mark patterns having a leading identifier field of digital bits, a trailing identifier field of digital bits and a field of digital synchronizing data located between said leading and trailing identifier fields. The leading identifier field of digital bits is electrically equivalent during reproducing while the medium is moving in a first direction to the trailing identifier field of digital bits while the medium is moving in a direction opposite to said first direction.

Abstract: A helical type tape recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape, with the physical blocks being recorded as double frames. Each double frame is recorded on a set of successive helical tracks, preferably 32 tracks. Each double frame has system format data interleaved with the user data block data which identifies the double frame as being of a particular type. The present invention is directed to the types of double frames that are used to begin a recording, particularly an append recording which involves recording by the system at a previously recorded tape which may have been recorded by a different system, as well as the types of double frame that are used to end a recording.

Abstract: A system for recording and reproducing data including user data on a magnetic tape having a number of partitions in which recording can be performed, the tape having at least one system zone in which user data is not recorded, the system having a table of data located near the beginning of the tape and near each system zone with the table including data identifying the physical location of the system zones and partitions and other sections of the tape.

Abstract: A helical tape recording and reproducing system which has longitudinal physical address track for recording physical address data relating to the physical layout of the tape and a logical address track that contains data relating to the content of the recorded helical tracks. Each address track has recorded segments with each of said segments containing data corresponding to a particular pair of helical tracks recorded in said helical recording area. Each segment has a multiple bit front field of a first predetermined timing synchronization bit pattern, a first predefined synchronizing word, a multiple bit segment information field of data, a second predefined synchronizing word and a multiple bit rear field of a second predetermined timing synchronization bit pattern.

Abstract: A tape recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. Each physical block is recorded as a double frame on a set of successive helical tracks, preferably 32 tracks. The system has the capability of verifying whether a physical block has been accurately recorded, and if not, the system rewrites the physical block downstream without stopping or repositioning the tape. If an accuracy verification confirmation does not occur until a next physical block is being recorded, the system demarks or invalidates that physical block being written, and rewrites both the failed physical block and that following physical block downstream of that physical block being written.

Abstract: A localized cooling apparatus is provided for individually cooling integrated circuit chips mounted on a circuit board for insertion into a computer backplane. The cooling apparatus consists of a circuit board occupying a first slot and having an integrated circuit chip mounted thereon, the performance of which is known to improve by cooling, a heat removal assembly consisting of a heat sink attached to a card edge portion and occupying an adjacent second slot, and a thermoelectric cooler intimately bonded to both the chip and heat removal assembly. A controller provides power via the connector of the second slot to the thermoelectric cooler and stabilizes the temperature of the chip to a predetermined value.