Writing Control Device for Unequal Data Distribution Across HDD Tracks
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Solution Overview
Problem
Conventional image forming apparatuses face performance limitations due to varying data transfer speeds across different tracks on HDDs, leading to inefficiencies in data storage and retrieval, particularly at the inner peripheral tracks where data transfer speed is low, resulting in write inhibit areas and increased costs when using multiple HDDs.
Innovation Solution
A writing control device that divides data into unequal portions and disperses them across multiple HDDs in parallel, with larger data sizes written on outer tracks and smaller sizes on inner tracks, optimizing data transfer by sectionalizing HDD storage areas and switching HDDs to maintain productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If data is written in order from outer peripheral tracks to inner peripheral tracks on a single HDD, then the writing process is simple, but the data transfer speed decreases significantly at inner tracks, reducing overall productivity
Solution Approach 1:
The patent divides data into multiple division data and stores them across multiple HDDs (second and third HDDs) rather than writing sequentially on a single HDD. This segmentation allows parallel writing operations, compensating for the slow transfer speed at inner tracks by distributing data across multiple storage devices, thereby maintaining high productivity without increasing writing control complexity
Solution Approach 2:
The patent combines multiple HDDs into a unified storage system where data is dispersed across multiple devices. By merging the storage capacity and operations of multiple HDDs, the system achieves higher effective transfer speeds that overcome the limitations of individual HDD inner track performance
2Productivity
If multiple HDDs are used with RAID striping to increase data transfer speed, then productivity is improved, but the inner peripheral tracks still become write inhibit areas, requiring additional HDDs to compensate
Solution Approach 1:
The patent applies different writing strategies to different portions of the storage system. Specifically, it directs larger division data to outer tracks of the second HDD where transfer speed is high, and smaller division data to inner tracks of the third HDD. This local optimization ensures that each HDD operates within its performance characteristics, eliminating write inhibit areas without requiring additional drives
Solution Approach 2:
The patent employs asymmetric data distribution where the second and third HDDs store different amounts of data (larger and smaller division data respectively) based on their track characteristics. This asymmetric allocation optimizes the use of available storage capacity while maintaining high transfer speeds, avoiding the need for symmetric RAID configurations that would require more HDDs
3Loss of time
If compression ratio is adjusted based on track position to equalize writing time, then inner track performance is improved, but the overall data transfer speed remains limited by the HDD's upper limit
Solution Approach 1:
The patent performs preliminary determination of division data sizes based on the data transfer speeds of different tracks before actual writing begins. By pre-calculating and allocating data portions according to track performance characteristics, the system avoids the need for compression adjustments during writing and directly achieves balanced writing times across all tracks, maintaining maximum transfer speeds
Data Source
AI summary
Disclosed is a writing control device including: a storing unit comprising N HDDs, N being an integer which is 2 or more; a data division unit configured to divide data to be written in the storing unit into N unequal division data; and a writing control unit configured to dispersedly store the N division data in the N HDDs in parallel, wherein the N division data include a first division data and a second division data having a larger data size than the first division data, and the writing control unit writes the second division data in tracks of a portion of the HDD, which is positioned on an outer side than a portion in which the first division data is written.