Hybrid Servo Patterns Augmenting Burst Fields for Disk Drive Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing servo systems in information storage systems using rotating disks have inefficiencies due to the large overhead of servo fields, which consume a significant portion of the recording surface and require separate fields for various functions like track identification, position error signal, and timing marks, limiting format efficiency and user-data capacity.
Innovation Solution
The introduction of hybrid servo patterns with augmented servo bursts that eliminate write-to-read gaps, allowing for integrated encoding of track identifier, sector number, and position error signal within the same bursts, and the use of Integrated Servo sequences that combine multiple servo functions into orthogonal sequences, reducing the need for separate fields and enabling gapless servo sectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate servo fields are used for track identification, position error signal, and timing marks, then servo system reliability is improved, but disk format efficiency deteriorates due to large overhead consuming significant recording surface
Solution Approach 1:
The patent combines multiple servo functions (track identification, position error signal, timing marks) into a single integrated servo field. The servo sector contains embedded timing marks and track identification codes within the same physical space, eliminating the need for separate dedicated fields for each function. This merging approach maintains all necessary servo functions while significantly reducing the overhead area on the disk surface, thereby increasing user-data capacity.
Solution Approach 2:
The servo field is designed to perform multiple functions simultaneously: it provides timing synchronization through embedded timing marks, track identification through Gray-coded track numbers, and position error signaling through specific signal patterns. This multi-functional design allows a single servo field to replace what would traditionally require multiple separate fields, improving format efficiency without compromising servo system reliability.
2Reliability
If write-to-read gaps are included before servo sectors, then servo field robustness is improved, but format efficiency deteriorates due to loss of recording space
Solution Approach 1:
The patent incorporates timing marks at the beginning of each servo sector, before the actual servo data. These preliminary timing marks provide synchronization information that enables the servo system to lock onto the correct timing reference before reading the track identification and position data. This preliminary action ensures robust servo field detection without requiring separate write-to-read gaps, as the timing marks are embedded within the servo sector structure itself.
3Measurement precision
If conventional servo patterns are used with separate fields for each function, then detection precision is improved, but device complexity increases due to multiple separate fields requiring independent processing
Solution Approach 1:
The patent merges track identification, position error signaling, and timing functions into a single integrated servo field structure. The servo sector contains embedded timing marks followed by track identification data in Gray code format, all within one continuous field. This integration reduces the number of separate fields that need to be independently processed, thereby reducing device complexity while maintaining detection precision through the preserved functional integrity of each servo element.
Data Source
AI summary
Disk drives are described that include a hybrid servo patterns in which the augmented servo burst fields, which can be Integrated Servo sequences, that provide the PES and also supply additional information such as a SAM, LSBs of the track identifier (TID), sector number, depending on the specific embodiment. Embodiments without write-to-read gaps before the servo sector SIDs are described. The augmented servo burst fields can be read after gapless writing of the preceding data area. For seeking operations the needed bits of the TID without having to detect or decode the Integrated Servo sequences or other augmented servo burst fields. Depending on the embodiment all or the most significant bits of the track identifier can be obtained during seeks by reading the TID fields passing under a read head as the read head moves across tracks without having to detect or decode the Integrated Servo sequences.