Abstract:
A data transfer delay compensation system for a data communications system having a first transceiver and a second transceiver wherein the first transceiver includes circuitry for transferring an external cycle reference signal and a cycle delay signal to the second transceiver. The second transceiver includes circuitry for transmitting the received cycle reference back to the first transceiver a given time period after receipt of the cycle reference. The first transceiver receives the cycle reference transmitted from the second transceiver and measures a phase difference between the received cycle reference and the external cycle reference signal in order to update the cycle delay signal.
Abstract:
A stable sorting system and method for use with a sort accelerator having a rebound sorter as a merger is disclosed. The stable sorting system maintains an output order of records which have equal keys. This output order is the same order of those records as they entered the rebound sorter. Stable sorting is maintained in both the sorting and the merging operations of the sort accelerator. An additional byte is inserted between the key and the data of a record to preserve record order for records having equal keys.
Abstract:
A memory array comprises N+1 memory elements. N memory elements store data and one or more error check bits respectively derived from the stored data. A separate N+1 memory element stores parity bits generated from the data stored in the N memory elements. These parity bits are stored in. To recover from data errors, data in each N memory element are first checked using their respective error check bits. If faulty data are detected in one of the N memory elements, an exclusive-or operation is performed involving data in the remaining N−1 memory elements and parity bits in the N+1 memory element. This recovers the faulty data in the one memory element.
Abstract:
An apparatus matches the configuration of a first station of a local area network to the configuration of the second station of the local area network. The first station detects a protocol advertisement from the second station that indicates a protocol in which the second station is capable of operating. The first station compares the indicated protocol of the second station to a protocol in which the first station is capable of operating. The first station determines, when the result of the comparison is negative, which of the first station and the second station is a higher priority station. The first station advertises, to the second station, a protocol capability of the first station, The first station changes the advertised protocol capability of the first station when it is determined that the first station is the higher priority station. The first station waits for the advertised protocol capability of the second station to change when it is determined that the second station is the higher priority station.
Abstract:
A data communication system, such as a local area network, is provided with a capability of transmitting isochronous data. Preferably the system conveys both isochronous data and non-isochronous data by time-multiplexing the data into a recurring frame structure on a four-bit nibble basis. An efficient encoding scheme permits transmission of both isochronous and non-isochronous data over existing media, such as twisted pair, without degrading bandwidth previously achieved for non-isochronous data over the same media, such as using an ethernet system. Bandwidth available for a particular isochronous source/sink is selectable and sustainable with a predefined granularity. The arriving data is de-multiplexed at the hub into separate channels for handling the separate streams by appropriate hardware. Preferably, the present invention can be implemented in a fashion that is transparent to already-installed media access controllers. Preferably, some components of the system can detect the frame-transmission capability of other components and, if such capability is lacking, can fall back to a mode compliant with existing capabilities.
Abstract:
An apparatus and method for transferring data between two entities in a time slot interchange fashion. The apparatus and method includes a buffer memory comprised of three sections to accommodate up to one cycle of skew between the two independently operating entities. Cycle start detection logic coupled to the two entities controls or, as implemented in the preferred embodiment, designates a physical location within the buffer memory for each of the three sections upon receipt of cycle start reference signals from the two entities.
Abstract:
A data integrity checking system and method for use with a sort accelerator having a rebound sorter as a merger. The data integrity checking system checks the integrity of data which has been processed by a sorting system wherein unsorted data has been received from and sorted data has been delivered to a host processor. Parity valves and checksum schemes are used. Sorted data is also checked for proper sorting by a sort order checker.
Abstract:
Support for a mixed network environment is provided which can contain multiple isochronous and/or non-isochronous LAN protocols such as Isochronous-Ethernet. Ethernet, isochronous-token ring, token ring, other isochronous-LAN or other LAN Systems. Support for a mixed environment includes a protocol detection mechanism which is embodied in a handshaking scheme. This handshaking scheme determines the signalling capability at the end points of the link and implements the correct protocol. This enables isochronous nodes and hubs to automatically detect the presence of Ethernet, token ring, or other LAN equipment at the other and of the network cable. If this detection occurs, the isochronous LAN equipment will fall-back to a LAN compliant mode of operation. Typically, only the hub will have the capability of operating at different networking modes, such as Ethernet, Token Ring isochronous modes. The hub will listen for some form of identification from the attached nodes as to the type of service to provide—isochronous or non-isochronous: Ethernet, token ring or other LAN service.
Abstract:
Support for a mixed network environment is provided which can contain multiple isochronous and/or non-isochronous LAN protocols such as isochronous-ethernet, ethernet, isochronous-token ring, token ring, other isochronous-LAN or other LAN systems. Support for a mixed environment includes a protocol detection mechanism which is embodied in a handshaking scheme. This handshaking scheme determines the signalling capability at the end points of the link and implements the correct protocol. This enables isochronous nodes and hubs to automatically detect the presence of ethernet, token ring, or other LAN equipment at the other end of the network cable. If this detection occurs, the isochronous LAN equipment will fall-back to a LAN compliant mode of operation. Typically, only the hub will have the capability of operating in different networking modes, such as ethernet, Token Ring isochronous modes. The hub will listen for some form of identification from the attached nodes as to the type of service to provide--isochronous or non-isochronous; ethernet, token ring or other LAN service.
Abstract:
A data communication system, such as a local area network, is provided with a capability of transmitting isochronous data. Preferably the system conveys both isochronous data and non-isochronous data by time-multiplexing the data into a recurring frame structure on a four-bit nibble basis. An efficient encoding scheme permits transmission of both isochronous and non-isochronous data over existing media, such as twisted pair, without degrading bandwidth previously achieved for non-isochronous data over the same media, such as using an ethernet system. Bandwidth available for a particular isochronous source/sink is selectable and sustainable with a predefined granularity. The arriving data is de-multiplexed at the hub into separate channels for handling the separate streams by appropriate hardware. Preferably, the present invention can be implemented in a fashion that is transparent to already-installed media access controllers. Preferably, some components of the system can detect the frame-transmission capability of other components and, if such capability is lacking, can fall back to a mode compliant with existing capabilities.