DC Component Control in RLL Encoding via Sub-Block Partitioning

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Solution Overview

Problem

Current data storage methods using the RLL method for hard disks face challenges in properly controlling the direct current (DC) component, leading to instability in digital data and inadequate storage density and reliability, especially when using the PMR method.

Innovation Solution

An encoding and decoding method that partitions input streams into sub-blocks, encodes based on reference sub-blocks to generate additional sub-blocks with redundant and non-redundant information, and rearranges them to control the DC component, including techniques like inverting sub-blocks based on digital sum thresholds and encoding states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a low-rate RLL method using a lot of redundant information is used to properly control the DC component, then the DC component control is improved, but the storage density is seriously reduced

Engineering Contradiction:

ImproveDC component controlVSAvoidstorage density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The input data stream is divided into multiple sub-blocks, and the encoding is performed selectively on specific sub-blocks rather than the entire stream. This segmentation allows redundant information to be added only where necessary for DC control, rather than uniformly across all data, thereby improving DC component control while minimizing the impact on storage density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The encoding method applies different processing to different portions of the data stream based on local characteristics. Specifically, encoding is applied to sub-blocks that contain forbidden patterns or require DC control, while other sub-blocks remain unchanged. This localized approach ensures that redundant information is added only where needed, improving DC control without unnecessarily reducing storage density across the entire data stream.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If a high-rate RLL method using only some redundant information is used, then the storage density is maintained, but the DC component control is insufficient

Engineering Contradiction:

Improvestorage densityVSAvoidDC component control

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The encoding rate is made dynamic rather than fixed. The method adaptively adjusts the amount of redundant information added based on the specific characteristics of each sub-block, such as the presence of forbidden patterns or DC component levels. This dynamic approach allows the system to maintain high encoding rates (preserving storage density) while still providing sufficient DC control where required by the data characteristics.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The method changes the encoding parameters (such as the ratio of redundant to original data) based on the specific requirements of different data segments. By adjusting these parameters locally rather than using a fixed high-rate encoding scheme, the system can maintain overall storage density while achieving adequate DC component control in critical areas.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If redundant information is added to control the DC component in PMR storage, then the DC component stability is improved, but the storage capacity is reduced

Engineering Contradiction:

ImproveDC component stabilityVSAvoidstorage capacity

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The data stream is segmented into sub-blocks, and DC control encoding is applied selectively to specific sub-blocks rather than the entire data stream. This reduces the total amount of redundant information added compared to uniform encoding schemes, thereby preserving more storage capacity while still achieving DC component stability in the critical segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of applying full-rate encoding to all data, the method applies partial encoding only to the extent necessary for DC control. By using only some of the redundant information (partial action) rather than maximum encoding rates, the system achieves adequate DC stability while minimizing the reduction in storage capacity.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8045625B2Encoding and decoding method to control a direct current (DC) component, and data processing apparatus performing the same

Publication Date: 2011.10.25 SAMSUNG ELECTRONICS CO LTD

AI summary

An encoding method includes partitioning an input stream into first sub-blocks and second sub-blocks, encoding the second sub-blocks based on a number and location of reference sub-blocks to generate third sub-blocks when at least one of the first sub-blocks corresponds to a forbidden pattern, and rearranging the first sub-blocks and the third sub-blocks to generate an output stream. The reference sub-blocks indicate the second sub-blocks that correspond to a reference pattern and the third sub-blocks includes a redundant information sub-block and non-redundant information sub-blocks. Thus, the encoding method may properly control a direct current (DC) component.