Ncr Corporation

Robert O Gunderson

David B Schuck

James E Kocol

Carson T Schmidt

Timothy G Goldsbury

Daniel J Marro

Barry L Loges

Jerrold L Allen

Chenyu Chao

Gregory D Brinson

Jerry K Herreweyers

James C Kocol

A data processing system including an addressable main memory for storing data and directly executable microinstructions, and a central processing chip having a data interface terminal and an instruction terminal. A processor memory bus is connected between the main addressable memory and the central processing chip data interface terminal. An instruction bus is connected between the central processing chip instruction terminal and the addressable memory. The directly executable microinstructions in the addressable main memory are fetched from the main memory by an apparatus which includes an instruction address circuit connected to the processor memory bus and the instruction bus. The instruction address circuit includes a virtual address register circuit for receiving a portion of a virtual address from the instruction bus, and a portion of the mentioned virtual address from the processor memory bus. A virtual-to-real translation circuit in the instruction address circuit translates the virtual address in the virtual address register to a real address in the addressable memory from which an executable microinstruction may be fetched.

Direct execution of software on microprogrammable hardware

A data processing system employing broadcast packet switching and having a plurality of subsystems and a system bus for linking the subsystems. The subsystems are grouped within stations that are each enclosed by a computer cabinet. The system bus includes a star coupler, first and second external transmission lines connecting each station to the star coupler, and first and second internal transmission lines within each station that are coupled to the first and second external transmission lines. The subsystems within each station are each coupled to the first and second internal transmission lines by a system bus interface. The system bus interface monitors the system bus for an idle condition, and passes a message from its subsystem to the system bus only when it detects an idle condition on the system bus. Each message on the system bus includes a postamble that is garbled by any system bus interface that detects an error in any message on the system bus. Each subsystem has a local memory that includes a mailbox for storing header information of messages that are to be copied by that subsystem. DMA circuitry in each system bus interface manages the operation of the mailbox in its subsystem. In alternate embodiments, the star coupler may be a magnetic star coupler or an electrical star coupler, and the system bus may be comprised of two channels, each channel including a star coupler and pairs of transmission lines connecting each station to the star coupler.

Data processing system wherein all subsystems check for message errors

Data processing system employing broadcast packet switching

Data processing system having dual-channel system bus

Data processing system wherein at least one subsystem has a local memory

Growing community of inventors

Poway, CA, United States of America

Robert O Gunderson