A processor intercommunication system for effecting information transfer among a plurality of processors, said system having a communications link with a plurality of station nodes, said processors each having at least one Input/Output I/O channel and said processors each periodically requiring exchanges of information such as control, data and status information with other processors in said system, such exchanges occurring by way of individual logical connections and transfer sessions between processors, the arrangement establishing and maintaining a multiplicity of such logical connections or transfer sessions between individual stations and other stations, said system comprising:
- a corresponding plurality of stations in said system, each of said stations being connected to a respective one of said station nodes for communication with any other station in said system by way of said communications link, each of said stations being attached to a respective one of said processors for controlling transfer of information such as said control, data, and status information between said processors over said communications link, such information being arranged in accordance with a variety of information frames, and each of said stations incorporating a modem for handling link related functions, such as information coding and modulation and the like, a link manager, said link manager providing logical frame management functions such as frame structuring, and the like, a channel interface controller, said channel interface controller providing interfacing for its station with its respective processor I/O channel, and the like, a storage section, said storage section incorporating a control storage array including a respectively assigned storage subsection for each station in the system for storing control information for the respective stations during transfer sessions, said storage section further incorporating a data storage array, including a respectively assigned storage subsection for each station in the system for storing data for the respective stations during transfer sessions, said storage section further incorporating a work queue storage array for storing work queues of pending task information during transfer sessions, and said arrays being commonly used by said link manager and said channel interface controller;
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- logic means in said channel interface controller and said link manager at each station operable in an initiating mode in response to control signals from the respective processor for initiating a logical connection with another station via said communications link by way of a requesting control frame to establish a transfer session, any station taking the initiative to establish a particular transfer session, i.e., the station which first sends a control frame being designated the master station and said logic means at each station being further operable in a receiving mode responsive to a received requesting control frame addressed to it and a conditioning signal from its respective processor to complete the logical connection, the station which does not have the initiative for a particular session but which accepts the requesting control frame from the master station for that particular session being designated a slave station, said logic means at each station being further operable to establish logical connections from the respective station to other stations via said communications link wherein any of said respective stations can simultaneously serve as a master in one transfer session and a slave in another transfer session through utilization of said control storage array, said data storage array and said work queue in a multiplexed manner under joint control of said link manager and said channel interface controller to thereby establish and maintain the required logical connections during operation of said system, whereby a multiplicity of interconnected master and slave station connections may exist within said system for accomplishing a multiplicity of exchanges of information in said system.