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Data Recovery Glossary

Base-Knowledge and glossary of data recovery and data recovery tools.

General Hard Drive Concepts:

• Start Chart
• ROM
• Servo Information
• Firmware Components
• Boot Sector

General Data Recovery Concepts:

• The Frequently Reasons of Data Lose
• Hard Disk Defect Classification
• Impossible Scope of Data Recovery

2. General Data Recovery Concepts

2.1 The Frequently Reason of Data Lose

Logically:

• Delete
• Format;Virus
• Be Protected
• Partition tab or MBR/DBR Broken

Firmware:

• Management Modules:Hard Disk couldn't work or work well
• Data Modules:Data lose or disordered

Physically:

• PCB Problem
• Bad Sector
• Motor Broken
• Platter Scratch or out of alignment
• Head Broken or out of alignment
• Hard Disk over heated
• Other Reasons

2.2 Hard Disk Defect Classification

Hard Disk Defect sector
Defect sector is the main defect in Hard Disk , it means the sectors couldn't be read.
-ECC (error correct code) Error: Every Hard Disk write a data to a sector, it will produce a ECC code. The next time read this sector, the OS will compare the ECC, if it is not correct, it would show error sector.
-Sector ID / Address mark not found.
Reason:

• Storage medium damage (scratch)
• Magnetic reduce (Frequently R/W)
• Head problem / OS problem

Servo Track Defect
Every track has one or some servo info, for head seek position and recognize the right track.
If one servo has problem, this track couldn't be read.
Represent:Couldn't partition / Format / even scan

2.3 Impossible Scope of Data Recovery
Logical problem

• Data has been overwritten or zerofill

• Key modules corrupt but couldn't find the donor FW
• P-list was broken and no backup file

• Strong scratch
• Platter overhead or break
• Head or PCB broken and no donor material