Flash Memory Defect Substitution for Hard Disc Reliability

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Solution Overview

Problem

In information recording apparatuses with hard discs, defects in specific regions lower the reliability of write and readout operations, requiring additional time for substitution processing that involves moving a magnetic head, which slows down data transfer.

Innovation Solution

A control unit sets a substituting region for defect regions in non-volatile flash memory, eliminating the need for magnetic head movement and rotational speed control, and manages this region using attribute information to prevent unintentional data loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If substitution processing is performed for defect regions on the hard disc, then reliability of write and readout operations is improved, but additional time is required for magnetic head movement which reduces productivity

Engineering Contradiction:

Improvereliability of write and readout operationsVSAvoidspeed of write and readout operations

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent creates a substituting region in the non-volatile cache memory that copies the functionality of defect regions on the hard disc. When a defect is detected, the system allocates a corresponding region in the non-volatile cache as a substitute, allowing data operations to continue without requiring magnetic head movement to physical substitute regions on the disc, thus maintaining reliability while improving operational speed.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The non-volatile cache memory acts as an intermediary between the host device and the hard disc. By handling defect substitution in the cache memory rather than on the hard disc itself, the system mediates the defect management process to avoid magnetic head movement, thereby maintaining both reliability and productivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the number of hard disc drives is reduced to save battery energy, then use of energy is improved, but write and readout speed may be reduced

Engineering Contradiction:

Improvebattery energy consumptionVSAvoidwrite and readout speed

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The system performs preliminary actions by pre-allocating substituting regions in the non-volatile cache memory before defects occur. This allows the cache to handle defect substitution independently, enabling the hard disc to operate at full speed without waiting for defect management operations, thus maintaining speed while reducing the need for multiple hard disc drives and saving battery energy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical defect management system (magnetic head movement to substitute regions on the hard disc) with an electronic substitution system in the non-volatile cache memory. This substitution eliminates the need for mechanical head movement during defect handling, maintaining high-speed operations while allowing for reduced hardware configuration to save energy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7913029B2Information recording apparatus and control method thereof

Publication Date: 2011.03.22 KK TOSHIBA

AI summary

According to one embodiment, an information recording apparatus has a control unit configured to control mutual transfer of information between each of a disc-shaped recording medium, a cache memory, and a non-volatile memory and the outside, control mutual transfer of information between the disc-shaped recording medium, the cache memory, and the non-volatile memory, and control to set a substituting region corresponding to a defect region generated in the disc-shaped recording medium in the non-volatile memory.