Burroughs, Inc.

Robert L Rawlings

Ronald D Mathews

Morris G Watson

James E Wollum

A data communication subsystem for operation with a main host computer, the subsystem involving a plurality of Front-End Controllers (each of which handles data transfers for a particular type of peripheral terminal and type of transmission line), a Data Communication Processor which controls the activity of the Front-End Controllers, a local 'autonomous' memory (sometimes called data communications memory) dedicated to storing instructions, control data, and information data primarily for data transfer operations, and a Basic Control Interface unit which ties together the autonomous memory, the Data Communications Processor, and the Front-End Controllers. The data communication subsystem includes means for sensing a halt or failure in the main host system and then operating in an 'autonomous' mode to continuously provide for data transfer operations independent of the main system condition. The data communication subsystem also provides means for storage of data (tanking) on disk files when the main system is halted. Such disk storage also alleviates memory space requirements for the main memory and the local autonomous memory. The concept of 'data communications memory' is applied as a memory space dedicated for data transfer operations. This memory space called 'data communications memory' may be made to reside in host system main memory, a local autonomous memory, or even in internal memory space within the Data Communications Processor. However, on halt of the main host computer system, the local autonomous memory will operate as the data communications memory directly available to the data communication subsystem and will work independently of a halt in the main host computer system.

Autonomous data communications subsystem

In a digital data communication network there is provided a data communications subsystem working in conjunction with a main host system having a central host processor and main memory. The data communications subsystem provides a data communications processor and a local autonomous data communications memory connected to a basic control interface unit which supports a plurality of front-end controllers. The data communications subsystem can sense a halt in the main system and operate autonomously and independently of the main host system during such down-time. The present disclosure describes a front-end controller-processor called an adapter cluster module which is used to control a plurality of line adapters, each of which communicates with remote terminals on low to medium speed transmission lines. Up to 16 such adapter cluster modules may be accommodated as front-end controllers within a single data communications subsystem. Each adapter cluster module can handle up to eight transmission lines operating in full duplex mode. A ROM memory area is provided for standard program routines. A RAM memory is provided for storage of special routines and instructions in addition to a scratchpad area for accumulation of a full message block before any interruption is made to the data communications processor requesting further data transfer instructions. Thus, a large magnitude of overhead operations are removed from the data communications processor which formerly was interrupted each time a byte of information was received by the adapter cluster module.

Adapter cluster module for data communications subsystem

A data communications subsystem operates with a main host computer having a central processor and main memory. The subsystem comprises: A data communications processor having its own internal memory for storing data transfer routines; and autonomous memory dedicated to storing data transfer instructions and control data; and a basic control module which includes a basic control interface unit connecting a plurality of front-end controllers. The basic control interface unit provides memory access paths for the front-end controllers to access data communications memory resources. The data communications processor provides address pointers to each of the front-end controllers whereby the selected front-end controller may access data transfer instructions from a data communications memory resource and then execute these instructions. The data transfer instructions are stored in 'command blocks' in a memory resource and are made accessible to the front-end controllers for execution of data transfer operations. In a 'non-autonomous configuration' the host system main memory is used for storage of command blocks and control data. This configuration is used with the type of front-end controllers known as broadband controllers using high speed transmission lines connected to peripherals and adapter cluster module controllers. In an 'autonomous' configuration, the command blocks are stored in autonomous memory and the front-end controllers may include, in addition, an added mix of a data communications disk controller (DCDC) for data storage on disk, and a store-to-store controller (SSC) for transfer of data between autonomous memory and the main memory independently of the data communications processor.

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El Toro, CA, United States of America

Robert L Rawlings