Magnetic Disk Postcode Selection for Format Efficiency
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Solution Overview
Problem
Magnetic disk devices face challenges in efficiently managing servo data, particularly in selecting appropriate postcodes for different regions to optimize format efficiency across conventional, shingled, and hybrid recording modes, leading to suboptimal data storage and retrieval processes.
Innovation Solution
A magnetic disk device with a controller that selects and writes specific postcodes of varying lengths to different regions based on format efficiency, using a system that includes a head for data writing and reading, and a system controller to manage the selection and placement of postcodes within servo sectors, enhancing format efficiency by adapting to different recording modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single postcode length is used for all regions, then the device complexity is reduced, but the format efficiency deteriorates
Solution Approach 1:
The patent applies local quality by using different postcode lengths for different regions of the magnetic disk. Specifically, an inner circumferential region uses a first postcode length while an outer circumferential region uses a second postcode length. This allows each region to have optimized servo data structure tailored to its specific recording characteristics, thereby improving format efficiency without significantly increasing overall device complexity.
2Productivity
If different postcode lengths are used for different regions, then the format efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent segments the magnetic disk surface into multiple regions (inner circumferential region and outer circumferential region), each with its own optimized postcode length. The controller is configured to select appropriate postcodes based on the current region, implementing a segmented approach that improves format efficiency while keeping the selection logic manageable through clear regional demarcation.
3Manufacturing precision
If conventional recording mode is used, then the manufacturing precision is maintained, but the productivity deteriorates
Solution Approach 1:
The patent implements a dynamic recording mode selection mechanism that adapts between conventional recording mode and shingled recording mode based on the region being accessed. The controller dynamically switches recording modes and corresponding postcode lengths to optimize for both precision (in inner regions using conventional mode) and productivity (in outer regions using shingled mode), thereby resolving the contradiction between manufacturing precision and data storage efficiency.
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a disk including a first region with a first format efficiency and a second region with a second format efficiency lower than the first format efficiency, a head that writes data to the disk and reads data from the disk, and a controller that selects a first postcode to be written to the first region from a plurality of postcodes with different lengths and writes the first postcode to the first region, and selects a second postcode to be written to the second region from a plurality of postcodes with different lengths and writes the second postcode to the second region.