Disk Drive Head-Zone Ordering for Sequential Data Rate Smoothing
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Solution Overview
Problem
Multi-head disk drives experience undesirable large fluctuations in sequential data rate due to format variations among disk surfaces caused by differences in head performance, leading to inconsistent data transfer rates across zones.
Innovation Solution
A method is implemented where the controller orders head-zone combinations from highest to lowest data rate, allowing sequential data writing to prioritize higher performing heads and minimize the use of lower performing heads until necessary, thereby smoothing data rate fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data is written to disk surfaces with format variations among multiple heads, then multi-head disk drive capacity is increased, but large fluctuations in sequential data rate occur
Solution Approach 1:
The controller pre-determines the data rate for each head-zone combination before the writing operation begins. This preliminary characterization allows the system to plan the writing sequence in advance to avoid data rate fluctuations, rather than reacting to fluctuations as they occur during writing.
Solution Approach 2:
The controller dynamically selects which head writes to which zone based on real-time data rate requirements. The writing sequence is adaptively adjusted during operation, switching between heads and zones to maintain a consistent data rate, rather than using a fixed writing pattern.
2Adaptability or versatility
If heads with different performance levels are used across disk surfaces, then manufacturing flexibility is improved, but data transfer rate consistency deteriorates
Solution Approach 1:
Each head-zone combination is assigned a specific data rate characteristic based on the actual performance of that head. The system treats each head-zone combination as having its own local quality parameter (data rate), and uses this information to optimize the writing sequence for that specific location rather than applying a uniform approach.
Solution Approach 2:
The controller changes the operational parameters (which head writes to which zone) based on the determined data rates. By dynamically adjusting the head-zone assignment parameters during the writing sequence, the system compensates for variations in head performance and maintains consistent overall data transfer rates.
3Ease of operation
If sequential writing is performed across zones with varying data rates, then writing simplicity is maintained, but data rate fluctuations increase
Solution Approach 1:
The controller uses the pre-determined data rates as feedback information to make intelligent decisions about the writing sequence. This feedback mechanism allows the system to automatically adjust which head writes to which zone to maintain optimal data rates, without requiring complex real-time monitoring during the actual writing process.
Data Source
AI summary
Systems and methods for writing a sequence of data to a disk drive using sorted data zones are provided. One embodiment includes a disk drive comprising one or more disks having a plurality of disk surfaces, wherein each disk surface comprises a plurality of data zones, each data zone having a data transfer rate; a plurality of heads, wherein each head is configured to write data to a respective one of the disk surfaces; and a controller configured to operate the plurality of heads to sequentially write a sequence of data blocks to the plurality of disk surfaces in accordance with an order of head-zone combinations ordered from highest data transfer rate to lowest data transfer rate, each head-zone combination corresponding to one of the heads and one of the data zones of the respective disk surface.