Magnetic Disk Device ATI Count Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic disk devices face issues with side erasure due to adjacent track interference (ATI) from leakage magnetic flux, which can lead to data corruption, especially as recording capacity increases and the number of disks grows, requiring effective management and refresh mechanisms to maintain data integrity.
Innovation Solution
A split actuator magnetic disk device with multiple controllers and heads, where internal log management units record and update ATI counts in volatile and non-volatile memory, and perform refresh processes when thresholds are exceeded, while transferring log data between system areas based on busy states to optimize performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of magnetic disks is increased to cope with increased recording capacity, then the recording capacity is improved, but the complexity of managing ATI counts across multiple disks and controllers increases
Solution Approach 1:
The patent divides the management of ATI counts by separating the management of first information (related to first head and first disk) from second information (related to second head and second disk). Each controller manages its own disk's system area independently, segmenting the overall management task into smaller, manageable units that can be handled separately by each controller.
Solution Approach 2:
The patent uses the volatile memory as an intermediary to temporarily store and manage ATI count information. The internal log management unit writes to the system area through this intermediary storage, allowing coordinated management between multiple controllers without direct interference, thus reducing management complexity while maintaining recording capacity.
2Reliability
If ATI count management is implemented to prevent side erasure, then data integrity is improved, but the device complexity increases due to additional management mechanisms
Solution Approach 1:
The system implements self-service by having each controller automatically manage its own disk's system area and ATI counts. The internal log management unit autonomously writes first information to the second system area and second information to the first system area without requiring external intervention, maintaining data integrity through self-managed refresh operations.
Solution Approach 2:
The patent merges the management of multiple ATI count tables into a unified approach where both first and second information are stored in system areas of respective disks. This consolidation allows coordinated management of ATI counts across multiple heads and disks, improving data integrity while streamlining the management mechanism.
3Reliability
If refresh operations are performed to prevent side erasure, then data reliability is improved, but the processing time and productivity are reduced
Solution Approach 1:
The patent implements periodic refresh operations where the internal log management unit periodically writes updated ATI count information to the system area. This periodic action ensures data reliability by regularly updating the counts while allowing normal operations to proceed between refresh cycles, minimizing the impact on processing speed.
Solution Approach 2:
The system performs preliminary actions by maintaining ATI count information in volatile memory before writing to the system area. This preliminary storage allows quick access and updates during normal operations, with the actual refresh write operations performed only when necessary, thus maintaining data reliability without continuously impacting processing speed.
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 effectively manages ATI counts and performs refresh operations to prevent data corruption, enhancing the reliability and performance of write/read processing in high-capacity magnetic disk devices by dynamically handling busy states and power cycles.
Implementation Method 1
data is erased can occur due to the influence of leakage magnetic flux or the like (Adjacent Track Interference: ATI) from the head when data is written
Implementation Method 2
a first head that writes data to the first disk and that reads data from the first disk
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a first disk having a first user data region and a first system area, a second disk having a second user data region and a second system area, a first head that writes data to the first disk, a second head that writes data to the second disk, a first actuator having the first head, a second actuator having the second head, a first controller that controls the first disk, the first head, and the first actuator, and a second controller that controls the second disk, the second head, and the second actuator, wherein the first controller records first information related to the first head and the first disk in the second system area.