Raid XOR operations to synchronous DRAM using a read buffer and pipelining of synchronous DRAM burst read data
First Claim
1. A memory interface controller, comprising:
- a read buffer to pipeline read data from a synchronous dynamic random access memory (SDRAM) in response to a plurality of consecutive SDRAM burst read requests;
a write buffer to store write data;
an exclusive or (XOR) engine to XOR the write data with read data from the read buffer; and
a write interface to write the resulting data from XORing the write data and the date from the read buffer to the synchronous dynamic random access memory.
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Accused Products
Abstract
A memory interface controller includes a read buffer to pipeline data from a synchronous dynamic random access memory (DRAM) in response to a plurality of consecutive SDRAM burst read requests, a write buffer to store write data, an exclusive or (XOR) engine to XOR the write data with the data from the read buffer, and a write interface to write resulting data from XORing the write data and the data from the read buffer to the synchronous DRAM. Data is pipelined in the read buffer by repeatedly issuing an SDRAM burst read request before data is transferred out of the synchronous DRAM in response to a previous SDRAM burst read request until a desired amount of data is stored in the read buffer. The memory interface controller thus can perform an external read-modify-write cycle for the synchronous DRAM. The synchronous DRAM can serve as a RAID (Redundant Array s of Inexpensive Disks) memory.
160 Citations
15 Claims
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1. A memory interface controller, comprising:
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a read buffer to pipeline read data from a synchronous dynamic random access memory (SDRAM) in response to a plurality of consecutive SDRAM burst read requests;
a write buffer to store write data;
an exclusive or (XOR) engine to XOR the write data with read data from the read buffer; and
a write interface to write the resulting data from XORing the write data and the date from the read buffer to the synchronous dynamic random access memory. - View Dependent Claims (2, 3, 4)
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5. A method of performing an external read-modify-write cycle for a synchronous DRAM (dynamic random access memory), comprising the steps of:
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pipelining data from a synchronous dynamic random access memory (SDRAM) in a read buffer in response to a plurality of consecutive SDRAM burst read requests;
storing write data in a write buffer;
XORing the write data with the data from the read buffer; and
writing the resulting data from XORing the write data with the data from the read buffer to the synchronous dynamic random access memory. - View Dependent Claims (6, 7, 8)
issuing an SDRAM burst read request before data is transferred out of the synchronous DRAM in response to a previous SDRAM burst read request.
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9. A bus/memory interface device, comprising:
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a synchronous dynamic random access memory controller to control a synchronous dynamic random access memory; and
a memory interface controller coupled to the synchronous dynamic random access memory controller, the memory interface controller comprising;
a read buffer to pipeline data from the synchronous dynamic random access memory (SDRAM) in response to a plurality of consecutive SDRAM burst read requests;
a write buffer to store write data;
an exclusive or (XOR) engine to XOR the write data with data from the read buffer; and
a write interface to write the resulting data from XORing the write data and the data from the read buffer to the synchronous dynamic random access memory. - View Dependent Claims (10, 11)
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12. A memory interface controller, comprising:
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a means for pipelining data from a synchronous dynamic random access memory (SDRAM) in response to a plurality of consecutive SDRAM burst read requests;
a means to store write data;
a means to XOR the write data with the data from the synchronous dynamic random access memory; and
a means to write resulting data from XORing the write data and the data from the synchronous dynamic random access memory to the synchronous dynamic random access memory. - View Dependent Claims (13, 14, 15)
a means for issuing an SDRAM burst read request before data is transferred out of the synchronous dynamic random access memory in response to a previous SDRAM burst read request.
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Specification