HDD Self-Servo Write Clock Generation Using Multi-Spiral Patterns
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hard disk drive (HDD) systems face increased CPU load and memory capacity requirements due to the need to execute servo processes for both auxiliary servo patterns and multi-spiral patterns simultaneously within one sampling cycle, while also reducing the area available for writing final patterns.
Innovation Solution
The HDD system eliminates auxiliary servo patterns, using multi-spiral patterns alone to position the electromagnetic transducer for self-servo writing, by generating a self-servo write clock and adjusting decoding gate intervals based on rotational synchronization components to match the timing with multi-spiral patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If auxiliary servo patterns are used to position the head before self-servo writing, then the head can be accurately positioned at the starting position, but the CPU load and memory capacity increase due to executing servo processes for both auxiliary and multi-spiral patterns simultaneously
Solution Approach 1:
The patent extracts and eliminates the auxiliary servo patterns from the system, retaining only the multi-spiral patterns for positioning. By removing the redundant auxiliary patterns, the system reduces CPU load and memory capacity while maintaining positioning accuracy through optimized use of multi-spiral patterns alone
Solution Approach 2:
The multi-spiral patterns are designed to serve multiple functions: they provide both the positioning information needed for head placement and the servo information for tracking control. This consolidation eliminates the need for separate auxiliary patterns, reducing system complexity while maintaining all necessary functions
2Measurement precision
If auxiliary servo patterns are written on the magnetic disk, then the head can be positioned for self-servo writing, but the area available for writing final patterns is reduced
Solution Approach 1:
The patent removes auxiliary servo patterns from the magnetic disk surface, eliminating the area they occupy. This increases the available area for writing final data patterns while maintaining positioning capability through the use of multi-spiral patterns that are integrated into the data recording area
3Productivity
If the sampling cycle is reduced to increase productivity, then more patterns can be written faster, but the area for writing final patterns is further reduced by auxiliary servo patterns
Solution Approach 1:
By eliminating auxiliary servo patterns, the patent removes the area constraint that limits productivity improvements. This allows for shorter sampling cycles and faster writing speeds without sacrificing valuable recording area, as the multi-spiral patterns provide sufficient positioning information without requiring separate auxiliary structures
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 approach reduces CPU load, memory capacity requirements, and increases the area for writing final patterns by eliminating the need for seed patterns, improving efficiency and reducing sampling cycle constraints.
Implementation Method 1
an arm which is rotated by a voice coil motor in accordance with a current supplied to a voice coil motor
Implementation Method 2
a head (electromagnetic transducer) reads magnetic information from the multi-spiral patterns
Implementation Method 3
a magnetic disk on which an intermediate pattern formed of a multi-spiral pattern for self-servo writing is formed
Data Source
AI summary
According to one embodiment, a recording device comprises: a recording medium, an arm, a positioning module, a self-servo write clock generator, and an on-track module. The positioning module positions the arm at a position at which the electromagnetic transducer detects a rotational synchronization component of an intermediate pattern comprised in the recording medium. The self-servo write clock generator generates a self-servo write clock based on the detected rotational synchronization component. The on-track module positions the electromagnetic transducer to the intermediate pattern serving as a position for starting self-servo write based on the generated self-servo write clock. Until the on-track module appropriately completes the positioning, the self-servo write clock generator sequentially changes a decoding gate interval corresponding to the intermediate pattern in accordance with the rotational synchronization component, and captures a spiral reproduction waveform.