International Business Machines Corporation

Rene R Castel

Jean L Calvignac

Edward Stanely Suffern

Kenneth James Barker

Jean Claude Dispensa

Gerard Dalboussiere

Wilburn D Draper

Jean-Louis J Calvignac

George M Calhoun

Yves J Huchet

Michel Kulakowski

Ruggero Ulivastro

The connection capability of a communication controller is extended. The communication controller includes a central control unit CCU, running a network control program NCP stored in a memory having a direct memory access facility through a DMA bus. The input/output bus of the communication controller and DMA bus are connected to line adapters, and channel adapters and a controller extension through a coupler which allows additional adapters to be connected to the controller. At initialization, a table is built into a coupler memory, which is then used in steady state mode for controlling the transmission of the messages to the additional users and the reception of the messages from the additional users, by improving the buffer unchaining and chaining processes into the NCP memory.

Coupling apparatus and method for increasing the connection capability

Information exchange method in a communications controller comprising a central control unit (CCU) associated with a storage that provides a number of parameter/status and data areas equal to the maximum number of interfaces to be managed by the controller. The storage contains a line vector table which indicates the address of each area assigned to each interface. The exchange of the parameter/status information and data on the input/output bus (IO5) uses a minimum number of input/output operations controlled by the program stored in the storage (3).

Method and device for exchanging information between terminals and a

In a data processing equipment handling communication lines connected to a central control unit through adapters and a CCU input/output bus, an error reporting device is provided in each adapter for reporting error conditions occurring in the adapter to the central control unit. The adapters are of the type including a microcode controlled microprocessor provided with input and output buses connected to the CCU input/output bus through an interface. The error reporting device in association with dedicated circuits in the interface insures the transmission of the error conditions occurring in the adapter to the central control unit, even when such error conditions affect the integrity of the microcode. When the error reporting device detects an error affecting the microcode integrity, it generates a hard stop signal which causes the operation of the microprocessor under the control of the microcode to be stopped and the error conditions to be transferred to the central control unit making use of the same paths as those used for reporting errors which do not affect the microcode integrity.

Device for reporting error conditions occurring in adapters, to the data

A line adapter for permitting the transfer of information between terminals and a bus connected to the central control unit CCU of a communications controller. The line adapter includes a microprocessor associated with a control memory and a scanner. A random access memory is split into zones, one zone being assigned to each line. During an initiating phase, the zones are personalized under the control of the microcode by sending initiating parameters (which are characteristics of the lines) to the memory, through an asynchronous path bus and external registers. Exchanges of temporarily-stored data between the CCU bus and the lines are carried out through cycle steal operations between the control memory and the random access memory.

Communication line adapter for use with a communications controller

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Vence, France

Rene R Castel