Flash Memory Controller Null Address Mapping
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Solution Overview
Problem
Conventional flash memory data storage devices waste system resources and cause delays due to accessing memory units with no data, as each physical address is mapped to a logical address, leading to unnecessary memory access and resource utilization when empty units are not utilized for data storage.
Innovation Solution
The method involves an address link table that maps logical addresses not associated with physical addresses to a null physical address, allowing the controller to identify and utilize empty memory units for data storage, and enables the host to write predetermined data to null physical addresses, eliminating mapping relationships and reducing resource consumption during data access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If each physical address is mapped to a logical address in the address link table, then data access is enabled, but system resources are wasted and delays occur when accessing empty memory units
Solution Approach 1:
The patent applies preliminary action by checking whether a logical address is mapped to a valid physical address before performing physical memory access. The controller预先 checks the address link table to determine if the mapped physical address contains valid data or is an empty/null address, thereby avoiding unnecessary physical access operations and saving system resources.
2Adaptability or versatility
If all memory units are accessible through logical address mapping, then data storage flexibility is improved, but empty memory units cannot be utilized by the controller for new data storage
Solution Approach 1:
The patent applies segmentation by dividing the address link table into two distinct types of mappings: valid mappings (logical address to non-null physical address) and invalid mappings (logical address to null physical address). This segmentation allows the controller to distinguish between occupied and empty memory units, enabling the controller to allocate empty memory units for new data storage while maintaining host access flexibility through logical addresses.
3Device complexity
If logical addresses are mapped to physical addresses for every host access, then address conversion is simplified, but unnecessary physical access occurs when the mapped memory unit contains no data
Solution Approach 1:
The patent introduces an intermediary mechanism by using the address link table as a mediation layer between logical addresses and physical addresses. Before performing physical access, the controller queries the address link table to obtain the mapped physical address and checks whether it is a valid non-null address. This intermediary check prevents unnecessary physical access operations while maintaining the simplicity of address conversion, thereby reducing system delay.
Data Source
AI summary
The invention provides a method for accessing a flash memory. In one embodiment, the flash memory comprises a plurality of memory units, each of the memory units has a physical address, and an address link table records a mapping relationship between a plurality of logical addresses and a plurality of physical addresses. First, first data to be written to a first logical address is received from a host. Whether the first data is predetermined data is the determined. Whether the first logical address is mapped to a null physical address is then determined according to the address link table. When the first data is the predetermined data and the first logical address is not mapped to the null physical address according to the address link table, the address link table is modified to map the first logical address to the null physical address.