Pseudo Port for a Communications Subsystem
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2005-Feb-03
Outboard processors that are utilized as multiplexers and connected by a common bus usually require a different hardware interface between the processors and the interface to the port or channel of the host system. This article describes a communication subsystem in a host system which utilizes microprocessors as outboard processors in which the handshaking mechanism normally done by the port-side hardware is emulated in the microcode of the outboard processors. The communication subsystem attachment supports three interfaces. The processor interface 12 communicates with the microprocessor, the device interface 11 provides the BSC/SDLC line adapter access to the microprocessor and the Port/Pseudo Port 15 assures commonality to the host system control store processor and any of the microprocessors that are cascaded.