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- 23 فبراير 2009
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Hard Disk Structure
Hard Disk Details (1)
Data recovery is necessary when source material fails and where no good backup exists, either Physical or Logical. There are two types of data recovery in the standard basic sense. One type of data recovery is when there is damage to the media and the pre-existing data need to be retrieved. This will usually require the media to be repaired.
The second form of data recovery is when files were purposely or accidently deleted. When this type of data recovery is necessary there is usually no damage to the media and standard software can be used to recover the data. This…
The hard drive knows nothing about your files and is not aware in any way of the content. That is the job of the Operating System (OS from here on). When the OS asks for a file, the OS will request a logical block from the drive; the drive will translate that to the physical location in CHS. An example is that it might request data from Cylinder 2500 at head 2 located on sector 234. The drive has many spare sectors and sometimes spare tracks to be used to compensate for errors and relocation of data. NOTE: Look at…
Slide 1289: The first thing a hard drive will do after it receives power is check for a return status from it’s chips to make sure the electronics are functioning. Then the drive will begin the self-check of its parts and wait for a return status. If both status checks are returned then the drive continues on to the next step and spin up the spindle.
Slide 1781: What is in the System Area Info. Each category is called a Module and is a UBA block.
1. Smart Data
2. System Logs
3. Serial Number
4. Model Numbers
5. P-List (Primary Defects List – i.e.: manufacture defect info that does not change)
6. G-List (Grown Defects Lists – sector relocation table)
7. Program Overlays – Firmware, Executable Code, or updates
8. Specific Tables like RRO – (recalibrate repeatable run-out and head offsets)
9. Zone Tables
10. Servo Parameters
11. Test Routines
12. Factory Defaults Tables
13. Recalibration Code Routines
14. Translator Data
a. Converts Logical and Physical Address to locations on the drive
b. Heads and Track Skewing Info
15. Security Data Passwords…
Slide 2221: When the drive is manufactured it is known that there is going to be errors in every drive. Drives use ECC to correct most errors and if ECC can correct the error then the sector is never marked as bad. If it is marked as bad, the drive puts the data in a bad block list. Most people know that their hard drive has a bad block table. What most people do not know is that their drive has TWO bad block tables.
1. P-List (Primary Defects List – manufacture defect info that does not change)
2. G-List (Grown Defects…
Slide 2840: The GMR (giant magnetoresistive) head is the current head used on most hard drives. This head uses high end physics I do not claim to understand. The only major difference is the way the head has been changed to read perpendicular. The GMR head has four layers, a sensing layer, a conducting layer, a pinned layer and an exchange layer. It was discovered that if you took two magnetic layers and aligned them opposite each other with a soft layer between them that the magnetic force would align themselves in parallel. When a bit of data passes under…
Slide 3791: The cause of the click is from four possible areas, all resulting in the SA not being able to be read.
1. System Area of the drive cannot be read because the platter is scratched.
2. The head itself has a problem and cannot read the SA area.
3. Preamp on Actuator to the Head has gone bad and is not passing the correct signal to the electronics
4. The firmware on the board is damaged and does not initialize. This is sometimes caused by static electricity walking across the carpet to install the drives, or there is a short on the board,…
Slide 4259: Head Replacement Section
This is the only section from last year I kept and it is because this is directly related to fixing this click of death problem.
NOTE: If there is only one platter it might be easier to move the platter than to move the assembly. You have to make that choice.
List of items needed:
The first step is to get a hard drive as close to identical as the bad drive you have that is a working drive. At the bottom of this paper you will find help about matching hard drives and serial numbers.
You need a clean…
List of items needed
The first step is to get a hard drive as close to identical as the bad drive you have that is a working drive. At the bottom of this paper you will find help about matching hard drives and serial numbers.
You need a clean area to work on with as little dust floating around as possible.
You will need about 1 hour to do this carefully
A screwdriver set with T3-T8. These are my favorite http://www.wihatools.com/200seri/278serie.htm
Post-it Notes
Other tools depending on the drive
Anti-Static Gloves ($5 at the local store)
Patience
]
Matching Serial Numbers on Hard Drives
This link is where I keep track of documentation on how each hard drive needs to be matched for a working donor drive. I get this any where I can, use it if you can, and if you happen to find something out please let me know so I can add it to the collection!
NOTES:
Drives with the same model number can still have different numbers of heads, therefore the board is different. It is possible to identify the number of heads in a drive: Maxtor,Quantum, Seagate from the serial numbers:
REFIRBUSHED DRIVES
REFIRBUSHIED drives cannot be used…
Data recovery is necessary when source material fails and where no good backup exists, either Physical or Logical. There are two types of data recovery in the standard basic sense. One type of data recovery is when there is damage to the media and the pre-existing data need to be retrieved. This will usually require the media to be repaired.
The second form of data recovery is when files were purposely or accidently deleted. When this type of data recovery is necessary there is usually no damage to the media and standard software can be used to recover the data. This…
The hard drive knows nothing about your files and is not aware in any way of the content. That is the job of the Operating System (OS from here on). When the OS asks for a file, the OS will request a logical block from the drive; the drive will translate that to the physical location in CHS. An example is that it might request data from Cylinder 2500 at head 2 located on sector 234. The drive has many spare sectors and sometimes spare tracks to be used to compensate for errors and relocation of data. NOTE: Look at…
Slide 1289: The first thing a hard drive will do after it receives power is check for a return status from it’s chips to make sure the electronics are functioning. Then the drive will begin the self-check of its parts and wait for a return status. If both status checks are returned then the drive continues on to the next step and spin up the spindle.
Slide 1781: What is in the System Area Info. Each category is called a Module and is a UBA block.
1. Smart Data
2. System Logs
3. Serial Number
4. Model Numbers
5. P-List (Primary Defects List – i.e.: manufacture defect info that does not change)
6. G-List (Grown Defects Lists – sector relocation table)
7. Program Overlays – Firmware, Executable Code, or updates
8. Specific Tables like RRO – (recalibrate repeatable run-out and head offsets)
9. Zone Tables
10. Servo Parameters
11. Test Routines
12. Factory Defaults Tables
13. Recalibration Code Routines
14. Translator Data
a. Converts Logical and Physical Address to locations on the drive
b. Heads and Track Skewing Info
15. Security Data Passwords…
Slide 2221: When the drive is manufactured it is known that there is going to be errors in every drive. Drives use ECC to correct most errors and if ECC can correct the error then the sector is never marked as bad. If it is marked as bad, the drive puts the data in a bad block list. Most people know that their hard drive has a bad block table. What most people do not know is that their drive has TWO bad block tables.
1. P-List (Primary Defects List – manufacture defect info that does not change)
2. G-List (Grown Defects…
Slide 2840: The GMR (giant magnetoresistive) head is the current head used on most hard drives. This head uses high end physics I do not claim to understand. The only major difference is the way the head has been changed to read perpendicular. The GMR head has four layers, a sensing layer, a conducting layer, a pinned layer and an exchange layer. It was discovered that if you took two magnetic layers and aligned them opposite each other with a soft layer between them that the magnetic force would align themselves in parallel. When a bit of data passes under…
Slide 3791: The cause of the click is from four possible areas, all resulting in the SA not being able to be read.
1. System Area of the drive cannot be read because the platter is scratched.
2. The head itself has a problem and cannot read the SA area.
3. Preamp on Actuator to the Head has gone bad and is not passing the correct signal to the electronics
4. The firmware on the board is damaged and does not initialize. This is sometimes caused by static electricity walking across the carpet to install the drives, or there is a short on the board,…
Slide 4259: Head Replacement Section
This is the only section from last year I kept and it is because this is directly related to fixing this click of death problem.
NOTE: If there is only one platter it might be easier to move the platter than to move the assembly. You have to make that choice.
List of items needed:
The first step is to get a hard drive as close to identical as the bad drive you have that is a working drive. At the bottom of this paper you will find help about matching hard drives and serial numbers.
You need a clean…
List of items needed
The first step is to get a hard drive as close to identical as the bad drive you have that is a working drive. At the bottom of this paper you will find help about matching hard drives and serial numbers.
You need a clean area to work on with as little dust floating around as possible.
You will need about 1 hour to do this carefully
A screwdriver set with T3-T8. These are my favorite http://www.wihatools.com/200seri/278serie.htm
Post-it Notes
Other tools depending on the drive
Anti-Static Gloves ($5 at the local store)
Patience
Matching Serial Numbers on Hard Drives
This link is where I keep track of documentation on how each hard drive needs to be matched for a working donor drive. I get this any where I can, use it if you can, and if you happen to find something out please let me know so I can add it to the collection!
NOTES:
Drives with the same model number can still have different numbers of heads, therefore the board is different. It is possible to identify the number of heads in a drive: Maxtor,Quantum, Seagate from the serial numbers:
REFIRBUSHED DRIVES
REFIRBUSHIED drives cannot be used…