Dedicated Servo Layer for Hard Disk Drive Clock Synchronization
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Solution Overview
Problem
Conventional data storage devices, such as hard disk drives, face challenges in achieving high precision in tracking the movement of read/write heads due to limited servo information availability, which affects storage capacity and power consumption, especially in smaller devices, and cannot perform both read and write operations simultaneously.
Innovation Solution
A data storage device with a dedicated servo layer that includes a plurality of servo patterns with preambles for synchronization, allowing for continuous servo readback and simultaneous read/write operations, enabling higher positioning accuracy and increased data recording density by using a phase lock loop circuit to generate a reference clock signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If embedded servo is used with single magnetic layer, then device complexity is reduced, but measurement precision of read/write head tracking deteriorates
Solution Approach 1:
The magnetic recording medium is segmented into two distinct layers: a first magnetic layer dedicated to storing user data and a second magnetic layer dedicated to storing servo information. This segmentation allows the servo system to continuously track head position with high precision while the data layer maintains storage capacity, resolving the contradiction between simplified embedded servo and precise tracking.
Solution Approach 2:
The invention adds a vertical dimension to the traditional planar servo structure by stacking a dedicated servo layer beneath the data layer. This dimensional change enables continuous servo information availability throughout the recording medium, improving tracking precision without significantly increasing horizontal device complexity.
2Measurement precision
If dedicated servo layer is added, then measurement precision of read/write head tracking is improved, but device complexity increases
Solution Approach 1:
The dedicated servo layer serves multiple functions simultaneously: it provides continuous position feedback for precision tracking, enables generation of reference clock signals for synchronization, and supports both read and write operations. This multi-functionality justifies the added structural complexity by delivering comprehensive performance improvements.
Solution Approach 2:
The servo patterns with preambles are pre-recorded on the dedicated servo layer before data operations. These preambles contain synchronization information that enables the read/write channel to lock onto the correct timing and frequency reference in advance, facilitating precise and synchronized read/write operations without real-time complexity.
3Ease of manufacture
If conventional single layer is used, then ease of manufacture is improved, but productivity of simultaneous read/write operations deteriorates
Solution Approach 1:
The recording medium is divided into separate servo and data layers, allowing each layer to be optimized independently. The servo layer can be manufactured with precise positional patterns while the data layer handles user information, enabling simultaneous read/write operations through dedicated servo information availability without complicating the overall manufacturing process.
Solution Approach 2:
The dedicated servo layer acts as an intermediary between the mechanical positioning system and the data read/write channel. It provides continuous position feedback and synchronization signals that mediate between head movement and data operations, enabling simultaneous read/write without interfering with the simplicity of the manufacturing process.
4Manufacturing precision
If servo information is only in servo wedges, then manufacturing precision requirements are reduced, but measurement precision of head position deteriorates
Solution Approach 1:
The dedicated servo layer contains continuous servo patterns with preambles throughout the recording medium, providing uninterrupted servo information as the head moves. This continuity enables constant head position detection and tracking without the gaps inherent in wedge-based servo systems, improving measurement precision while maintaining reasonable manufacturing tolerances through standardized pattern repetition.
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 solution enhances tracking precision and allows for simultaneous reading and writing, improving storage capacity and reducing power consumption by maintaining synchronization through the dedicated servo layer, even during writing operations.
Implementation Method 1
generating a reference clock signal for synchronization of at least one of a read and a write operation based on the servo pattern
Data Source
AI summary
Various embodiments provide a data storage device. The data storage device includes a recording medium having a dedicated servo layer for providing servo information. The dedicated servo layer may include a plurality of servo patterns, wherein each servo pattern includes a preamble providing information for synchronization of at least one of a read and a write operation of the data storage device.