Memory Read Validation Using Address Flags and Check Codes
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Solution Overview
Problem
Memory systems face issues with erroneous data transmission due to incorrect reading of data from nonvolatile memory, leading to wrong data being sent to the host.
Innovation Solution
A memory system with a controller that manages mapping information using a first management table and flags, ensuring valid data is transmitted by checking the integrity of data using check codes and flags, and determining the correctness of data before transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data is read from nonvolatile memory without verification, then reading speed is improved, but data integrity deteriorates due to erroneous reads
Solution Approach 1:
The patent applies preliminary action by setting flags in the management table before data writing occurs. These flags mark the validity status of data in advance, enabling quick verification during reading without requiring complex real-time checks, thus maintaining high read speed while ensuring data integrity through pre-established validation markers.
Solution Approach 2:
The patent implements feedback by using the flag information from the management table to verify data validity during reading operations. The controller reads the flag associated with the physical address and uses this feedback information to determine whether to transmit the read data to the host, creating a simple yet effective validation loop that ensures data integrity without significant performance penalty.
2Reliability
If flags and check codes are implemented for data verification, then data integrity is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the data verification function into separate, manageable components: the management table stores flag information for multiple physical addresses, and the controller processes verification by accessing specific flags based on read commands. This segmentation allows the system to verify data integrity through simple table lookups rather than complex real-time calculations, maintaining low controller complexity while ensuring reliability.
Solution Approach 2:
The patent uses copying by storing flag information in the management table as a copy or representation of data validity status. Instead of directly verifying data integrity through complex algorithms, the system copies the validity state into the management table where it can be quickly accessed during reading operations, simplifying the verification process while maintaining data integrity.
3Reliability
If mapping information is managed with flags, then correctness of transmitted data is improved, but management table size increases
Solution Approach 1:
The patent applies local quality by assigning individual flags to specific physical addresses in the management table, allowing each data location to have its own validity status tracked independently. This localized flag assignment enables precise verification of only the specific data being read, rather than requiring comprehensive verification of all data, thus maintaining high correctness while minimizing the impact of increased management table size.
Data Source
AI summary
According to one embodiment, a memory system includes a controller. The controller manages a plurality of flags corresponding to a plurality of physical addresses. In response to receiving a read command from a host, the controller acquires from a first management table a physical address mapped to a logical address specified by the read command, and reads data from a nonvolatile memory based on the acquired physical address. The controller determines whether or not to transmit the read data to the host based on whether a current status of the flag corresponding to the acquired physical address is set to a first value indicating valid data or to a second value indicating invalid data.