Magnetic Disk Head Position Correction via Zone Servo Demodulation
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Solution Overview
Problem
Conventional magnetic disk devices face inefficiencies in data formatting due to high servo occupancy ratios in double zone servo areas, leading to reduced data capacity and formatting efficiency, primarily caused by gaps between zone servo areas that prevent immediate post code writing after burst data.
Innovation Solution
The magnetic disk device eliminates gaps between zone servo sectors on the front and rear sides in double zone servo areas, allowing the post code to be written immediately after the rear zone servo sector, thereby reducing servo occupancy and enhancing data formatting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gaps are maintained between zone servo sectors to prevent data overwriting, then data integrity is preserved, but servo occupancy ratio increases and data capacity decreases
Solution Approach 1:
The patent applies preliminary action by writing the post code immediately after the burst data in the front zone servo sector, before the head moves to the rear zone servo sector. This advance preparation allows the post code to be in place before any potential overwriting could occur, eliminating the need for protective gaps between servo sectors while ensuring data integrity.
Solution Approach 2:
The patent implements dynamics by changing the servo sector structure from static separated zones with gaps to a dynamic configuration where the post code is strategically positioned and written at optimal timing. This dynamic approach allows the system to adapt the servo occupancy ratio based on the writing sequence and head position, maximizing data capacity while maintaining reliability.
2Productivity
If gaps are eliminated between zone servo sectors, then data capacity and formatting efficiency improve, but risk of post code erasure increases
Solution Approach 1:
The post code is written in advance immediately after the burst data, before the head reaches the rear zone servo sector. This preliminary action ensures the post code is securely in place before any operations that might affect it, allowing gap elimination while protecting against erasure.
Solution Approach 2:
The patent enables continuous writing operations without interruptions or gaps between front and rear zone servo sectors. By maintaining continuous useful action in data writing while strategically positioning the post code, the system achieves higher formatting efficiency without compromising post code preservation.
3Quantity of substance
If post code writing is delayed until after rear zone servo sector, then servo occupancy ratio is reduced, but formatting time increases
Solution Approach 1:
The post code is written preliminarily immediately after the burst data in the front zone servo sector, rather than waiting until after the rear zone servo sector. This advance writing reduces the total formatting time while still achieving optimal servo occupancy ratio by eliminating the need for delayed post code writing operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration increases data capacity and improves formatting efficiency by eliminating gaps, allowing for more data storage without erasing post codes, thus optimizing the use of disk space.
Implementation Method 1
a read head for reading data from the disk
Implementation Method 2
a write head for writing data to the disk
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a disk including a zone servo boundary area including a first area of a first servo frequency, a second area of a second servo frequency, and a third area of the first servo frequency, in a servo area, a head, and a controller demodulating first servo data of the first area to derive a position of the head and demodulating first corrected data of the third area to correct the position of the head. The first area, the second area, and the third area are aligned in order in a traveling direction. The first area and the second area are adjacent to each other in a circumferential direction of the disk. The second area and the third area are adjacent to each other in the circumferential direction.