Host Calculation Unit for eMMC Write Data Size Estimation
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Solution Overview
Problem
In information processing apparatuses with embedded Multi Media Cards (eMMC) and NAND flash memories, the Write Amplification Factor (WAF) causes discrepancies between specified and actual data sizes written, making it difficult for host systems to accurately determine the amount of data written to NAND flash memories, as eMMC does not store actual write data sizes.
Innovation Solution
An information processing apparatus is designed with a storage unit, a write control unit, a calculation unit, and a notification unit to estimate and calculate the actual data size written to the storage unit based on specified write data sizes, using a WAF management table to manage estimated WAF values for different types of eMMCs, allowing for accurate data size notifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the host system writes data to the NAND flash memory through eMMC, then data storage is achieved, but the actual write data size cannot be accurately determined due to Write Amplification Factor
Solution Approach 1:
The patent introduces an intermediary calculation unit that acts as a mediator between the host system and the eMMC. This unit calculates the actual write data size by multiplying the specified write data size by the WAF value, thereby recovering the lost information about actual data written to the NAND flash memory without requiring the eMMC to directly report this information
Solution Approach 2:
The patent implements a feedback mechanism where the calculated actual write data size is fed back to the host system through the notification unit. This allows the host system to monitor and manage the actual storage capacity consumption and memory lifespan based on the recovered write data size information
2Device complexity
If the eMMC does not store actual write data sizes, then the storage device structure remains simple, but the host system cannot manage storage capacity accurately
Solution Approach 1:
The patent applies self-service by having the host system's calculation unit perform the computation of actual write data size using the WAF value. Instead of requiring the eMMC to store and report this information (which would increase device complexity), the host system independently calculates and manages the write data size information itself
3Ease of operation
If the host system cannot know the actual data size written, then the system operation is simple, but storage overflow and data integrity cannot be ensured
Solution Approach 1:
The patent applies preliminary action by calculating the actual write data size immediately after each write operation occurs. The calculation unit computes the actual size by multiplying the specified size by WAF, and the notification unit promptly notifies the host system. This timely feedback enables the host system to proactively manage storage capacity and prevent overflow before it occurs, thereby ensuring data integrity
Data Source
AI summary
An information processing apparatus includes a storage unit configured to store data, a write control unit configured to instruct the storage unit to write data, a calculation unit configured to calculate, for each of a plurality of writes of data to the storage unit, a data size estimated to be actually written to the storage unit, based on a write data size specified by the write control unit, and a notification unit configured to issue a notification based on a total of the data sizes calculated by the calculation unit.