Flow controller for shared bus used by plural resources
First Claim
1. A method of controlling access by plural resources to a bus that is shared by said resources, each of said resources having a first storage means for storing data to be transmitted onto said bus and a second storage means for receiving data from said bus, each of said first and second storage means having a data storage capacity, said method comprising the steps of:
- a) obtaining fullness information on an amount of data contained in each of said first storage means and said second storage means with respect to the respective capacity thereof; and
b) determining from said fullness information which resource is to have access to the bus for transmitting data from its first storage means and which resource is to have access to the bus for receiving data into its second storage means.
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Accused Products
Abstract
The flow controller utilizes intelligent adapters to connect plural resources to a bus and a central arbiter that decides which adapters have access to the bus for the next bus cycle. Each adapter has an input buffer for transmitting data onto the bus, an output buffer for receiving data from the bus and a target register that identifies the destinations of the data in the input buffer. Each adapter communicates over control lines separate from the bus the following information: if its input buffer is nearly full, if its output buffer is either nearly empty or nearly full and the contents of its target register. The central arbiter gives highest priority to those adapters having nearly full input buffers with data for non-full output buffers, next highest priority to those adapters having nearly empty output buffers with data targeted by an input buffer and lowest priority to adapters with less than full input buffers having data for non-empty output buffers.
50 Citations
20 Claims
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1. A method of controlling access by plural resources to a bus that is shared by said resources, each of said resources having a first storage means for storing data to be transmitted onto said bus and a second storage means for receiving data from said bus, each of said first and second storage means having a data storage capacity, said method comprising the steps of:
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a) obtaining fullness information on an amount of data contained in each of said first storage means and said second storage means with respect to the respective capacity thereof; and b) determining from said fullness information which resource is to have access to the bus for transmitting data from its first storage means and which resource is to have access to the bus for receiving data into its second storage means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A data processing system having plural resources that share a bus interconnecting said resources, each of said resources having a first storage means for storing data to be transmitted onto said bus and a second storage means for receiving data from said bus, each of said first and second storage means having a data storage capacity, said data processing system comprising:
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a) means for obtaining fullness information on the amount of data contained in each of said first storage means and said second storage means with respect to the respective capacity thereof; b) means for selecting from said fullness information which resource is to have access to the bus for transmitting data from its first storage means and which resource is to have access to the bus for receiving data into its second storage means; and c) means for granting said selected resources access to said bus. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A flow controller for use in a data processing system that has plural resources that communicate over a shared bus, said flow controller comprising:
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a) plural adapters connected to said bus, there being at least one adapter for each resource, each adapter comprising a transmitting buffer, a receiving buffer and a target register, said target register of each adapter containing information on the receiving buffers targeted by data in the respective transmitting buffer; b) an arbiter that is connected to each adapter by control line means, said control line means for transmitting to said arbiter from each adapter information regarding fullness of the respective transmitting buffer, emptiness and fullness of respective receiving buffer and contents of the target register into a respective arbiter target register located in said arbiter, said control line means also for transmitting to each of said adapters from said arbiter information regarding if an adapter is to access the bus with either its transmitter buffer or its receiving buffer. - View Dependent Claims (19, 20)
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Specification