Storage Device Prefetching via Meta Key Address Mapping
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Solution Overview
Problem
Current disk drive technologies face challenges in improving access performance and recording density, particularly in managing logical block addresses to enable efficient data reading and writing operations, especially with the shingle-write scheme which requires dynamic address allocation to maintain recording density.
Innovation Solution
The method involves using meta keys in address mapping to prefetch data based on logical block addresses, allowing for dynamic address conversion and allocation, which enables efficient data reading and writing by optimizing the allocation of virtual bands and logical bands on the storage medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dynamic address allocation is used to maintain recording density in shingle-write scheme, then recording density is improved, but access performance deteriorates due to increased seek times
Solution Approach 1:
The patent applies preliminary action by performing prefetch operations to read data into the cache buffer before it is actually requested by the host. The storage device predicts which data blocks will be needed next based on the current read position and prefetches them in advance, so that when the host requests the data, it is already available in the cache, eliminating the need for additional seek operations and reducing access time while maintaining the dynamic address allocation required for shingle-write recording density
2Ease of operation
If data is read directly from storage medium without prefetching, then access simplicity is maintained, but access performance deteriorates due to sequential read operations
Solution Approach 1:
The storage device applies self-service by autonomously managing the prefetching process without requiring host intervention. The controller automatically identifies data to be prefetched, reads it into the cache buffer, and manages the timing of these operations, thereby improving access performance while keeping the host's interface simple and unchanged. The host continues to issue simple read commands without needing to know about or manage the prefetching mechanism
3Ease of operation
If prefetch operations are performed without address mapping optimization, then data retrieval is simplified, but recording density deteriorates in shingle-write scheme
Solution Approach 1:
The patent introduces an address mapping table as an intermediary between the logical block addresses used by the host and the physical locations on the storage medium. This mapping table enables the controller to translate host requests into precise physical addresses, allowing optimized prefetch operations that respect the dynamic address allocation requirements of shingle-write scheme while maintaining simple data retrieval interfaces for the host
Data Source
AI summary
Apparatuses and methods for prefetching data are disclosed. A method may include receiving a read request at a data storage device, determining a meta key in an address map that includes a logical block address (LBA) of the read request, wherein the meta key includes a beginning LBA and a size field corresponding to a number of consecutive sequential LBAs stored on the data storage device, calculating a prefetch operation to prefetch data based on addresses included in the meta key, and reading data corresponding to the prefetch operation and the read request. An apparatus may include a processor configured to receive a read request, determine a first meta key and a second meta key in an address map, calculate a prefetch operation based on addresses included in the first meta key and the second meta key, and read data corresponding to the prefetch operation and the read request.