Abstract: Flow control signals in half-duplex and full-duplex networks are initiated and maintained based on the detected number of data bytes stored in a receive buffer from payload data of received data packets. If the number of stored data bytes exceeds a predetermined threshold, the network interface initiates flow control. Alternatively, the decision to initiate flow control may be based upon the rate at which the receive buffer is emptied compared to the number of stored data bytes in the receive buffer, or the rate the data bytes are stored into the receive buffer. The duration of the flow control is calculated as a wait time interval selected in response to the number of stored data bytes. The wait time may be selectively set as an integer multiple of slot times, or as a time interval based on the number of stored data bytes relative to the removal rate.

Abstract: A system identifies transmission routes between a user and a desired destination site on a wide area communications network, such as the Internet. The system then detects transit characteristics for each of the transmission routes. A user can request the level of activity on the routes. Thus, the user can be apprised of the existence of possible congestion in any attempt to access the desired destination site.

Abstract: A method of identifying computer screens is disclosed. The method is particularly useful in identifying IBM host screens in script creation and playback. According to the method, a signature is composed for a given screen. The signature comprises characteristics of a given screen which differentiate that screen from substantially different screen displays. For an IBM host screen, signature composition is based upon the screens protected fields. The protected fields are further processed by removing transient information such as the date and time.

Abstract: A multiprocessing system includes a plurality of data processing subsystems each coupled to an interprocessor communications bus through a corresponding interprocessor communications interface. The interprocessor communications interface corresponding to each data processing subsystem includes a receive FIFO buffer unit, a transmit FIFO buffer unit, and a control circuit. When a data processing subsystem desires to transfer data to another processing subsystem, the data processing subsystem packetizes the data in a variable word-length transfer packet which includes a header having a size field and a target field. The data processing subsystem causes the transfer packet to be stored within the transmit FIFO buffer unit. When a valid transmit packet is stored with the transmit FIFO buffer of the interprocessor communications interface corresponding to a particular processing subsystem, the associated control unit requests mastership of the interprocessor communications bus and transmit packet.