Overview
Modern computer system hard drives can contain a massive amount of data. So when a hard disk fails, and there are no recent backups available, data recovery is the only option available.
Introduction
A hard disk consists of a number of component parts. Each of which has its own failure modes.
1. Electronics
2. Mechanics
3. Firmware
4. Logical
Electronics
The circuit board on a hard disk is the ‘brain’ of the hard disk and a single component failure will render the drive useless. Data recovery from hard drives with electronics failures will require highly skilled electronics engineers who are able to fix the drive temporarily in order to recover the data.
There are also electronic components inside the hard disk that are necessary for the correct functionality of the hard disk and consists of the head pre-amplifier circuit.
Mechanical
The critical mechanical parts of a hard disk comprise of, the actuator arm, the motor and the platters. (There are other Mechanical parts, vibro-acoustic components, filters, VCM Magnets, etc, but these are less critical).
The majority of mechanical failures involve the Head pre-amplifier. Whilst this is not exactly a mechanical failure, the method that the head pre-amp is fixed to the head stack means that when it fails it involves the replacement of the entire head stack assembly.
The next biggest cause of failure is motor failure. This is a very significant problem and requires specialist equipment so that platter alignment is not lost when removing and replacing the motor. Main problems with motors are burnt out coils and seized bearings.
Firmware
The firmware region or System Area (SA) is a section on the hard disk where the manufacturer’s proprietary information such as
- Zone Tables
- SMART Logs
- Head maps
- ROM Overlays
- Security Data
- ROM overlays.
- Translator Tables
- Grown Defect Maps
and many others
For a hard disk to function properly it is vital that the Firmware Zone is error free. Repairing the Firmware on a hard disk is a highly skilled job and requires specialist equipment. Making a mistake when changing the information in the Firmware of a hard disk can render a drive useless.
Logical
Logical problems are where there is no physical problem with the hard disk and it is fully functional. Logical problems are where you are no longer able to access the data, for example, the user has deleted the files, the computer has come under virus attack. The skill set of the engineer requires an understanding of how the operating system that the files were stored on works. Also, knowledge of the structure of individual file types so that quality of files can be determined on a bulk and individual basis.
Recovering Data from Hard Drives
MjM Data Recovery Ltd
written by DavePF \\ tags: Data Recovery