US 4,232,366 AGranted

Bus for a data processing system with overlapped sequences

AssigneeDigital Equipment Corporation

InventorsJohn V. Levy, David P. Rodgers, Robert E. Stewart, Richard J. Casabona

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Abstract

A digital data processing system including an interconnection for the various elements that constitute the system. Each element that connects to the interconnection is called a nexus. For one element to communicate with another element, the one element, as a commanding nexus, seeks control of the interconnection and then transmits a command and address of a storage location in the other element when it receives control of the interconnection. Control is then relinquished unless the one element is to send data to the other element whereupon the data is sent immediately. If data is to be retrieved, the other element retrieves the data, requests control of the interconnection and, when it receives control, transmits the data onto the interconnection with an identification of the one element. The one element then retrieves the data from the interconnection when it recognizes its own identification. If the other element is a memory element, it also contains storage file for storing commands and data if it already is operating in response to another element's command.

Claims43

Dependent claims

A data processing system comprising

A. timing means for generating timing signals, that define successive transaction intervals,
B. system interconnection means including:
i. bus access control signal interconnection means for transferring bus access control signals,
ii. information signal interconnection means for transferring information signals, and
iii. confirmation signal interconnection means for transferring confirmation signals,
C. a plurality of nexus means each including:
i. bus access control means connected to said bus access control signal interconnection means and to said timing means for transferring bus access control signals and for controlling the access of its respective nexus means to said system interconnection means in response to bus access control signals,
ii. information transfer means connected to said information signal interconnection means, said bus access control means, and said timing means for transferring information signals, and
iii. confirmation transfer means connected to said confirmation signal interconnection means, said information transfer means, and said timing means for indicating the status of an information transfer a predetermined interval after the information transfer by transferring confirmation signals,
said information transfer means and said confirmation transfer means being responsive to the timing signals from said timing means to establish transaction sequences each comprising a plurality of successive transaction intervals, each transaction sequence including an information transfer interval and a subsequent confirmation interval, said information transfer means transferring information during the information transfer interval of a particular transaction sequence and said confirmation transfer means transferring corresponding confirmation signals during the confirmation interval of that particular transaction sequence, said system interconnection means being able to transfer information signals and confirmation signals corresponding to different transaction sequence during a particular transaction interval whereby plural transaction sequences are overlapped.

7 more elements

In a data processing system, including timing means for generating timing signals that define successive transaction intervals, and a system interconnection means including bus access control signal interconnection means for transferring bus access control signals, information signal interconnection means for transferring information signals, and confirmation signal interconnection means for transferring confirmation signals, a nexus means comprising:

A. bus access control means connected to said bus access control signal interconnection means and to said timing means for transferring bus access control signals and for controlling the access of its respective nexus means to said system interconnection means in response to bus access control signals,
B. information transfer means connected to said information signal interconnection means, said bus access control means, and said timing means for transferring information signals, and
C. confirmation transfer means connected to said confirmation signal interconnection means, said information transfer means, and said timing means for indicating the status of an information transfer a predetermined interval after the information transfer by transferring confirmation signals,
said information transfer means and said confirmation transfer means being responsive to the timing signals from said timing means to establish transaction sequences each comprising a plurality of successive transaction intervals, each transaction sequence including an information transfer interval and a subsequent confirmation interval, said information transfer means transferring information during the information transfer interval of a particular transaction sequence and said confirmation transfer means transferring corresponding confirmation signals during the confirmation interval of that particular transaction sequence, said system interconnection means being able to transfer information signals and confirmation signals corresponding to different transaction sequences during a particular transaction sequence whereby plural transaction sequences are overlapped.

1 more element

Dependencies are inferred from the claim text.