US 4,290,102 AGranted

Data processing system with read operation splitting

AssigneeDigital Equipment Corporation

InventorsJohn V. Levy, David 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.

Claims12

Dependent claims

A data processing system including a first data means, a second data means including at least one storage location, transfer means including timing, function, identification, address and confirmation signal conveying means connected to said first data means and said second data means for transferring information between said first and second means and timing means connected to said timing signal conveying means for transmitting timing signals for establishing consecutive transfer intervals:

A. said first data means including means for transmitting onto said transfer means during a first transfer interval one of a plurality of commands, each command having a function signal portion for defining a transfer function to be performed, an identification signal portion for identifying said first data means and an address signal portion for identifying a location in said second data means to or from which the transfer of data is to occur, said first data means transmitting the function, identification and address signal portions onto said function, identification and address signal conveying means in said transfer means, and further including means for receiving confirmation signals from said confirmation signal conveying means in the transfer means during a subsequent transfer interval a predetermined number of transfer intervals after the first transfer interval,
B. said second data means including:
i. control means connected to said timing signal conveying means for controlling a transfer in response to signals from said timing means,
ii. command responsive transfer means connected to said control means, said function signal conveying means and said address signal conveying means, responsive to the receipt of a command for transferring data between the location identified by the address portion received from said address signal conveying means and said transfer means,
iii. identification means connected to said control means and said identification signal conveying means for storing the identification portion from said identification signal conveying means that identifies said first data means, and iv. confirmation means connected to said confirmation signal conveying means, said timing signal conveying means and said command responsive transfer means responsive to the receipt of a command from said first data means for transferring a confirmation signal on said confirmation signal conveying means said predetermined number of transfer intervals after said command responsive transfer means has received the command.

2 more elements

A data storage unit that connects to a data processing system including means for transmitting information signals including data and commands, means for transmitting first and second control signals for controlling the transfer of the information signals, means for transmitting tag signals for identifying the information signals as data or commands, means for transmitting identification signals for identifying the source of information signals that are identified as commands, and information connection means, tag connection means, identification connection means and control connection means for conveying the information, tag, identification and control signals respectively to and from said data storage unit, said data storage unit comprising:

A. addressable storage location means for storing data signals,
B. control means for establishing control states in response to first control signals on the control connection means,
C. interfacing latch means connected to said control means for storing the information, tag, identification and second control signals during a predetermined one of the control states,
D. tag means connected to said control means and said interfacing latch means for decoding the tag signals thereby to determine the nature of the information signals.
E. transfer means connected to said information connection means and said addressable storage location means for affecting transfers of data to and from the information connection means in response to the function signals and the address signals that are transferred with a command,
F. identification latch means connected to said tag means, said interfacing latch means and said control means for storing the identification signals from the identification connection means when said tag means decodes a command, and
G. identification circuit means connected to said tag means, said identification connection means and said control means for utilizing the signals from said identification connection means during the operation of said transfer means when said tag means decodes data.

4 more elements

Dependencies are inferred from the claim text.