Solid State Storage Threshold Carrying for Fast Wake-Up
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Solution Overview
Problem
Current solid state storage devices struggle to quickly respond from sleep mode after heavy cycling, leading to timeout failures due to inadequate threshold settings.
Innovation Solution
A process is implemented where adjusted threshold information is reused based on die and superblock, allowing for quicker read operations by determining and storing optimal thresholds for heavily cycled cells, reducing the need for time-consuming recalibration during system wake-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If solid state storage devices are heavily cycled and then enter sleep mode, then power consumption is reduced, but the device cannot respond quickly enough when woken up, causing timeout failures
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing adjusted threshold values for heavily cycled cells before entering sleep mode. When the device wakes up, these pre-computed thresholds are immediately available for use, eliminating the need for time-consuming recalibration during wake-up. This allows the device to maintain low power consumption during sleep while achieving fast response times upon waking.
2Measurement precision
If traditional threshold recalibration is performed during wake-up from sleep mode, then accurate read operations are achieved, but the process is too time-consuming and causes timeout failures
Solution Approach 1:
The patent performs threshold calibration in advance during normal operation or before sleep mode, storing the adjusted threshold values in the memory device. Upon waking from sleep mode, the pre-calculated thresholds are immediately available, eliminating the need for time-consuming recalibration while maintaining accurate read operations. This resolves the contradiction between threshold accuracy and wake-up time.
Solution Approach 2:
The patent creates a copy of the threshold information and stores it within the memory device itself, specifically in the superblock associated with each die. This copied threshold data can be quickly retrieved during wake-up without requiring external recalibration, thus reducing wake-up time while maintaining read accuracy.
3Speed
If adjusted threshold information is stored for each die and superblock, then fast wake-up is achieved, but storage capacity is consumed
Solution Approach 1:
The patent stores the adjusted threshold information in the superblock, which is a shared structure associated with each die. This superblock serves multiple functions: it stores metadata about the die, tracks wear levels, and now also stores the adjusted threshold values. By utilizing the existing superblock structure for multiple purposes, the patent avoids consuming additional dedicated storage capacity while still achieving fast wake-up performance.
Data Source
AI summary
An instruction to read at least a portion of a superblock is received where the superblock is stored on at least a first solid state storage die. It is determined if adjusted threshold information, associated with the first solid state storage die and the superblock, is stored. If it is determined that adjusted threshold information is not stored, then an adjusted threshold is determined and a read is performed on the first solid state storage die using the determined adjusted threshold. If it is determined that adjusted threshold information is stored, then a read is performed on the first solid state storage die using the stored adjusted threshold information.