Flash Memory Boot Reliability via Segmented Region Rewriting

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Solution Overview

Problem

Existing electronic devices with flash memory face challenges in ensuring reliable startup and proper rewriting of programs, as they may fail to start up if the flash memory's storage contents are incomplete during rewriting, and there is a risk of unauthorized rewriting without proper authentication.

Innovation Solution

A rewritable nonvolatile memory configuration with a first region for processing programs and a second region for boot and rewrite programs, where the first specific portion stores access information for the boot program, allowing sequential erasure and writing of storage contents, and requiring identification information for authentication, ensuring complete writing and preventing unauthorized access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the flash memory stores the rewrite program inside itself, then the device complexity is reduced and costs are lowered, but the reliability of startup is compromised because the program may become incomplete during rewriting

Engineering Contradiction:

Improvedevice complexityVSAvoidstartup reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The flash memory is divided into a first region for storing the program to be rewritten and a second region for storing the boot program and rewrite program. This segmentation allows the critical boot and rewrite programs to be isolated in a separate region that is accessed first during startup, ensuring that the device can always boot reliably even if the program in the first region becomes incomplete during rewriting.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second region containing the boot program and rewrite program is prepared in advance and configured to be accessed first during the boot process. This preliminary arrangement ensures that the essential programs for startup and rewriting are available before any rewriting operations begin, preventing startup failures even if rewriting is interrupted.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the electronic device provides a separate means for rewriting flash memory, then the reliability of rewriting is improved, but the device complexity increases and costs rise

Engineering Contradiction:

Improverewriting reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The flash memory contains a rewrite program stored within its own second region, enabling the memory to perform self-rewriting operations without requiring external rewriting means. This self-service approach reduces device complexity and eliminates the need for additional external rewriting components while maintaining rewriting functionality through the internally stored rewrite program.

Inventive Principle:

Principle #25Self-service

3Quantity of substance

If the program to be rewritten is stored in a region accessed first upon boot-up, then the storage space is utilized efficiently, but the startup reliability is compromised after rewriting

Engineering Contradiction:

Improvestorage space utilizationVSAvoidstartup reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The flash memory is segmented into two distinct regions: the first region for the program to be rewritten and the second region for the boot program and rewrite program. This segmentation ensures that the boot program remains in a protected region that is accessed first during startup, while the first region can be freely rewritten without compromising startup reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of storing the boot program in the first region that is rewritten, the patent inverts the arrangement by placing the boot program in the second region that serves as the source for rewriting operations. This inversion ensures that the critical boot program is preserved and used as the basis for rewriting, rather than being the target of rewriting operations.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS7418542B2Rewritable, nonvolatile memory, electronic device, method of rewriting rewritable, nonvolatile memory, and storage medium having stored thereon rewrite program

Publication Date: 2008.08.26 SHARP KK

AI summary

A rewritable, nonvolatile memory includes a first region having stored therein a processing program which allows an electronic device to perform a process, and having a first specific portion which is accessed first upon boot-up by the electronic device; and a second region having stored therein a boot program and a rewrite program. Upon erasing storage contents of the first region, the storage contents of the first region are erased by the rewrite program such that a storage content of the first specific portion is erased last. Upon writing storage contents into the first region, new storage contents are written into the first region by the rewrite program such that a storage content of the first specific portion is written first.