Magnetic Disk Device Cross Track Interval Optimization
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Solution Overview
Problem
Current magnetic disk devices face challenges in efficiently managing data recording and reading due to variations in cross track intervals, which affect bit error rates and read performance, especially under external vibrations.
Innovation Solution
A magnetic disk device with a dual recording mode capability, utilizing a write head and multiple read heads to set minimum and maximum cross track intervals for normal and shingled recording regions respectively, allowing for adaptive data recording and reading strategies to maintain performance across different radial positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If shingled recording is used to increase storage capacity, then productivity is improved, but reliability deteriorates due to variable cross track intervals affecting read performance
Solution Approach 1:
The disk surface is divided into multiple radial regions, each with distinct recording modes (normal recording in inner region, shingled recording in outer region). This segmentation allows optimization of each region for its specific function, maintaining read reliability in the inner region while achieving high storage capacity in the outer region.
Solution Approach 2:
Different radial regions of the disk are assigned different recording characteristics. The inner radial region uses normal recording with fixed cross track intervals for reliable reading, while the outer radial region uses shingled recording with variable cross track intervals for high density storage. Each region's local properties are optimized for its specific purpose.
2Reliability
If multiple read heads are used to read tracks with variable cross track intervals, then reliability is improved, but device complexity increases
Solution Approach 1:
The read head is designed with multi-functionality to handle both normal recording and shingled recording modes. The same read head can read tracks with fixed cross track intervals (normal mode) and variable cross track intervals (shingled mode), eliminating the need for separate read heads for different recording modes and reducing overall device complexity.
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a disk including a normal recording region written in a normal recording and a shingled recording region written in a shingled recording, a head including a write head and a plurality of read heads, the head moving on the disk by rotation about a rotation axis, and a controller which selects and executes the normal recording and the shingled recording, wherein a first minimum value of a cross track interval in the radial direction of the disk between two read heads in the plurality of read heads in the normal recording region is smaller than a first maximum value of the cross track interval in the shingled recording region.