Memory Read Verification Using Physical-Address Descrambling
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Solution Overview
Problem
Existing storage devices face challenges in accurately detecting physical address misreads in data transfer from non-volatile memory devices, leading to incorrect data retrieval and inefficiencies in error correction mechanisms.
Innovation Solution
Implementing a descrambling process seeded with the intended physical address, followed by cyclic redundancy checks (CRC) to verify correct data retrieval, and optionally using tags within the data to confirm the correct physical address.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller uses LBA verification to protect against physical address misreads, then data integrity is improved, but the verification fails when data is rewritten to different physical addresses maintaining the same LBA mapping
Solution Approach 1:
The patent segments the verification process into two independent components: LBA verification and physical address verification. The physical address verification is implemented as a separate mechanism using descrambling with physical address seeds, allowing it to operate independently from LBA verification and detect misreads that LBA verification misses.
Solution Approach 2:
The patent introduces an intermediary verification mechanism (physical address verification through descrambling) that acts as a mediator between the controller and memory device. This intermediary checks the actual physical address used during data retrieval, providing an additional layer of verification that complements LBA checking.
2Measurement precision
If application-level checks are implemented to detect physical address misreads, then detection capability is improved, but system complexity and fragmentation increase
Solution Approach 1:
The patent implements self-service by having the memory device automatically perform physical address verification through the descrambling process. The memory device itself generates the verification result by attempting to descramble data with the provided physical address seed, eliminating the need for complex external verification mechanisms.
Solution Approach 2:
The descrambling mechanism serves multiple functions: it both decrypts the data and simultaneously verifies the physical address. This multi-functionality reduces system complexity by combining verification capabilities into an existing operational process rather than adding separate verification infrastructure.
3Measurement precision
If p-tags are added to data to verify physical addresses, then verification accuracy is improved, but storage capacity and ECC protection are reduced
Solution Approach 1:
The patent uses copying by creating a verification copy of the physical address information through the descrambling seed mechanism. Instead of storing additional verification data in the memory array, the system creates a functional copy of the address verification capability through the descrambling process, using existing data bits for dual purposes.
Solution Approach 2:
The patent changes the parameter of verification from storing explicit address tags in the data to using the descrambling seed as a verification key. This parameter change transforms the verification mechanism from a space-consuming approach to a computation-based approach that uses existing data structure parameters.
Data Source
AI summary
A storage device may detect when data transferred from a memory device is read from a correct physical address on the memory device. The storage device includes a memory device to store data wherein data stored on the memory is accessed by referencing physical addresses on the memory device. A controller on the storage device may send a read instruction to the memory device to read data at a first physical address. When the controller receives the data from the memory device, the controller may descramble the data with a seed based on the first physical address. The seed is supplied by the controller. The controller may also perform a check and determine when an expected value is absent from the data. The controller may detect that the data is read from a second physical address when the controller is unable to retrieve the expected value from descrambled data.