Flash Memory Controller Trim Sector Bitmap Management

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In flash memory-based storage devices, deleted files are not effectively managed, leading to unnecessary operations like merge and garbage collection, which reduce performance and waste valid storage space due to invalid files being treated as valid data.

Innovation Solution

A storage device with a controller that performs an invalidation operation using a trim command, configuring a trim sector bitmap by region units and managing it using an LBA region table, allowing for efficient logging and memory management to prevent unnecessary operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the storage device performs merge operations or garbage collection operations on invalid files, then the storage device can manage deleted files, but the performance of the storage device lowers

Engineering Contradiction:

Improvefile managementVSAvoidperformance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The host device performs preliminary invalidation of deleted files by setting the invalidation bit in the trim sector bitmap before the storage device needs to perform merge or garbage collection operations. This allows the storage device to quickly identify and skip invalid files during subsequent operations, improving performance while maintaining reliable file management.

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If invalid files are stored like valid data, then the storage device can maintain storage capacity, but the valid storage space of the storage device is reduced

Engineering Contradiction:

Improvestorage capacityVSAvoidvalid storage space

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The storage device segments the storage space into valid and invalid regions by using the trim sector bitmap to mark invalid files. The LBA region table further divides the bitmap into manageable regions, allowing the storage device to efficiently distinguish between valid and invalid spaces and optimize allocation accordingly, preventing valid storage space from being wasted.

Inventive Principle:

Principle #1Segmentation

3Productivity

If the storage device manages trim sector bitmap by a region unit, then the controller can efficiently manage memory, but the device complexity increases

Engineering Contradiction:

Improvememory management efficiencyVSAvoidcontroller structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The controller segments the trim sector bitmap into multiple regions using the LBA region table, where each region corresponds to a specific LBA range. This segmentation allows the controller to manage memory more efficiently by processing only relevant regions rather than the entire bitmap, improving productivity while the structured approach to segmentation keeps the added complexity manageable through systematic organization.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9032138B2Storage device based on a flash memory and user device including the same

Publication Date: 2015.05.12 SAMSUNG ELECTRONICS CO LTD

AI summary

Disclosed is a storage device which includes a flash memory storing data; and a controller controlling the flash memory and performing an invalidation operation in response to a trim command of a host, wherein the controller configures a trim sector bitmap using trim information provided from the host at the invalidation operation and manage the trim sector bitmap by a region unit.