Non-Volatile Storage Metadata for Valid Data Identification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need to efficiently identify and migrate valid user data on non-volatile media during garbage collection operations in data storage devices that use logical block address indirection, as existing methods do not effectively reuse old physical locations containing invalid data.
Innovation Solution
The solution involves using metadata to associate each physical location with a logical block address (LBA) and implementing a garbage collection process that reads metadata to distinguish between valid and invalid data, allowing for the migration of valid data to new locations while updating the mapping table to ensure accurate data storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LBA indirection is used to store user data on non-volatile media, then data can be rewritten to new physical locations, but old physical locations containing invalid data cannot be efficiently reused
Solution Approach 1:
The patent introduces metadata as an intermediary layer between the LBA mapping table and physical data locations. This metadata contains validity flags that enable the garbage collection process to efficiently identify and migrate only valid data, thereby resolving the contradiction by enabling rapid reuse of physical locations while maintaining LBA indirection flexibility
2Productivity
If garbage collection operation is performed to migrate valid data, then old physical locations can be erased and reused, but the process is inefficient without effective valid data identification
Solution Approach 1:
The patent implements preliminary action by maintaining metadata that continuously tracks the validity status of data at each physical location. This pre-computed validity information is available before garbage collection operations begin, allowing the system to immediately identify valid data without time-consuming scanning or analysis during the garbage collection process itself
3Difficulty of detecting and measuring
If metadata is used to associate physical locations with LBAs, then valid data identification becomes possible, but system complexity increases
Solution Approach 1:
The patent applies local quality by implementing metadata in a distributed manner where each physical location has its own associated metadata entry containing validity information. This localized approach allows valid data identification without requiring complex global analysis or centralized tracking structures
Data Source
AI summary
A data storage device is disclosed including a non-volatile media having a first and a second plurality of physical locations, the first plurality of physical locations storing user data and the non-volatile media storing first metadata associating each of the first plurality of physical locations with a logical block address (LBA), and a mapping table including a mapping of each LBA to a current physical location. The data storage device further includes control circuitry that reads the first metadata to obtain a first plurality of LBAs, reads the mapping table to determine a current physical location for the first plurality of LBAs, and compares the current physical location of each of the first plurality of LBAs to a corresponding one of the first plurality of physical locations to identify valid user data in the first plurality of physical locations for migration into the second plurality of physical locations.