Segmented memory transfer and message priority on synchronous/asynchronous data bus
First Claim
1. A data transfer apparatus employing a data bus having a synchronous mode and an asynchronous mode for communication between a first memory unit and a second memory unit, comprising:
- means for determining a need for memory transfer;
means, responsive to said means for determining, for searching a plurality of memory segments in the second memory unit for a valid data record stored in one of said plurality of memory segments;
means for communicating said valid data record from the second data unit to the first memory unit in the asynchronous mode when said means for searching finds a valid data record; and
means for communicating an empty data record from the second data unit to the first memory unit in the asynchronous mode when said means for searching does not find a valid data record.
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Accused Products
Abstract
Apparatus and method for transferring segmented memory between memory units determines a need for memory transfer and searches a memory unit segment by segment until a valid data record is found. This valid data record is conveyed to another memory unit via the asynchronous mode. If a valid data records is not found within a predetermined amount of time, a message identifying the memory segment last searched is conveyed. If no remaining valid data records are found, a message with no information is conveyed. Priority is given to asynchronous messages.
37 Citations
22 Claims
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1. A data transfer apparatus employing a data bus having a synchronous mode and an asynchronous mode for communication between a first memory unit and a second memory unit, comprising:
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means for determining a need for memory transfer; means, responsive to said means for determining, for searching a plurality of memory segments in the second memory unit for a valid data record stored in one of said plurality of memory segments; means for communicating said valid data record from the second data unit to the first memory unit in the asynchronous mode when said means for searching finds a valid data record; and means for communicating an empty data record from the second data unit to the first memory unit in the asynchronous mode when said means for searching does not find a valid data record. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A data transfer apparatus employing a data bus having a synchronous mode and an asynchronous mode for communication between a first memory unit and a second memory unit, comprising:
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means for determining a need for memory transfer; means for communicating said determined need for memory transfer in the asynchronous mode; means for receiving a message conveyed in the asynchronous mode from the second memory unit in response to said communicated need; means for interpreting said received message; means for storing information from said received message when a valid data record is interpreted from said received message; and means for saving a location number from said received message when a valid data record is not interpreted from said received message. - View Dependent Claims (10, 11)
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12. A method of data transfer by a data bus having a synchronous mode and an asynchronous mode for communication between a first memory unit and a second memory unit, comprising the steps of:
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determining a need for memory transfer; searching a plurality of memory segments in the second memory unit for a valid data record stored in one of said plurality of memory segments in response to said determining step; communicating said valid data record from the second data unit to the first memory unit in the asychronous mode when said step of searching a plurality of memory segments finds a valid data record; and communicating an empty data record from the second data unit to the first memory unit in the asynchronous mode when said step of searching a plurality of memory segments does not yield a valid data record. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A method of data transfer by a data bus having a synchronous mode and an asynchronous mode for communication between a first memory unit and a second memory unit, comprising the steps of:
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determining a need for memory transfer; communicating said determined need for memory transfer in the asynchronous mode; receiving a message conveyed in the asynchronous mode from the second memory unit in response to said communicated need; interpreting said received message; storing information from said received message when a valid data record is interpreted from said received message; and saving a location number from said received message when a valid data record is not interpreted from said received message. - View Dependent Claims (21, 22)
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Specification