ECC Memory Partial-Write Buffering Without Read-Modify-Write
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Solution Overview
Problem
Partial writes in ECC-enabled memories require additional cycles due to the need for read-modify-write operations, which impact system throughput and increase area overhead, especially when access sizes are less than the memory word size.
Innovation Solution
A memory system with a data buffer that stores a full data word after a partial write operation, allowing subsequent partial writes to read from the buffer instead of the memory, thereby eliminating the need for read-modify-write operations and reducing cycle time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If read-modify-write operation is used for partial writes to ECC enabled memory, then data integrity is maintained, but the number of cycles increases and throughput decreases
Solution Approach 1:
The patent pre-loads the entire data word into the memory controller's data buffer during the first partial write operation. This preliminary action allows subsequent partial writes to the same memory location to read from the buffer rather than performing full read-modify-write cycles, thereby improving throughput while maintaining data integrity through buffer-based operations
2Manufacturing precision
If read-modify-write operation is used for partial writes, then correct ECC calculation is achieved, but additional cycles are required
Solution Approach 1:
The patent introduces a data buffer as an intermediary component within the memory controller. This buffer stores the current data word and allows partial write operations to modify it without requiring a full read-modify-write cycle to memory. The buffer acts as a mediator that enables faster partial writes while the ECC calculation unit continues to operate on the buffer contents, maintaining ECC accuracy without the time penalty of repeated memory accesses
3Speed
If data buffer is added to store full data words, then subsequent partial writes are faster, but area overhead increases
Solution Approach 1:
The data buffer in the patent is designed to serve multiple functions: it stores current data words for partial write operations, provides temporary storage for ECC calculation, and enables both read and write operations without requiring separate buffer structures. This multi-functionality allows the same buffer resource to improve various memory operations (partial writes, ECC updates) without proportionally increasing area overhead
Data Source
AI summary
A memory system includes a memory and a memory controller coupled to the memory. The memory controller includes a data buffer configured to store a full data word as a result of a partial write operation, wherein for a subsequent partial write operation, data is read from the data buffer.