Rewriting Initial Sectors in Shingled Magnetic Recording Drives
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Solution Overview
Problem
Hard-disk drive (HDD) devices face issues with initial sector weak writes and adjacent track erasure due to inadequate head protrusion during write operations, especially in shingled magnetic recording (SMR) where preheating methods are imprecise and can lead to data loss or adjacent track erasure.
Innovation Solution
A method that involves rewriting the initial sectors of a data track after the last sectors on the track have been written and before moving to the next track, using a write cache to add blocks for rewriting these sectors, with the preheating function disabled to prevent weak writes and adjacent track erasure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preheating function is enabled to improve head protrusion for initial sectors, then weak writes are reduced, but adjacent track erasure occurs due to excessive heat
Solution Approach 1:
The system performs a preliminary write operation to the initial sectors before the main write sequence, allowing the write head to achieve proper protrusion position in advance. This preliminary action prepares the head for subsequent writes without requiring continuous preheating that would cause adjacent track erasure.
Solution Approach 2:
The system implements periodic rewriting of initial sectors interspersed within the main write sequence. Rather than continuous preheating, the head periodically returns to rewrite initial sectors, maintaining proper protrusion while allowing cooling periods that prevent adjacent track erasure.
2Object-affected harmful factors
If preheating function is disabled to prevent adjacent track erasure, then data loss from erasure is reduced, but initial sector weak writes occur due to inadequate head protrusion
Solution Approach 1:
The system performs a preliminary write operation to the initial sectors before the main write sequence, allowing the write head to achieve proper protrusion position in advance. This preliminary action prepares the head for subsequent writes without requiring continuous preheating that would cause adjacent track erasure.
Solution Approach 2:
The system uses feedback from the preliminary write operation to adjust head position and write parameters for the main write sequence. The successful completion of preliminary writes confirms proper head protrusion, enabling reliable subsequent writes without preheating.
3Reliability
If initial sectors are rewritten multiple times, then write reliability is improved, but writing time increases
Solution Approach 1:
The system performs a preliminary write operation to the initial sectors before the main write sequence, allowing the write head to achieve proper protrusion position in advance. This preliminary action prepares the head for subsequent writes without requiring continuous preheating that would cause adjacent track erasure.
Solution Approach 2:
The system implements periodic rewriting of initial sectors interspersed within the main write sequence. Rather than continuous preheating, the head periodically returns to rewrite initial sectors, maintaining proper protrusion while allowing cooling periods that prevent adjacent track erasure.
Data Source
AI summary
Technologies are described herein for rewriting the initial sectors of a data track on a recording medium of a storage device in order to reduce the occurrence of initial sector weak writes and/or adjacent track erasure. Upon receiving a write command at the storage device, a plurality of sequential segments on the recording media targeted by the write command is determined. The plurality of sequential segments is written to the recording medium, and then data is rewritten to an initial segment of the plurality of sequential segments.