HD Doctor Blog

 When the substitution (Assign) mechanism is used in a drive the latter records to the ID field of a BAD sector the flag of the relocated sector and writes to the data field the number of the reserved sector, i.e. the one, which should be accessed for data recording or reading. As a rule, it is the first available sector after user data area. (figure 2.).

 Figure 2. Method of rededicated sector.
  During data read/write operations accessing the defective sector drive controller will read the flag and assigned address and reposition the heads to the reserved zone in order to perform reading/writing from/to a good sector. Defective sectors in that case will disappear, but the drive will…

Firmware data is necessary for functioning of internal HDD circuits and as a rule it remains hidden from users.

Firmware data can be subdivided into the following types:
 

Servo information or servo fields;
 Low-level format;
 Resident firmware microcode (operational programs);
 Configuration tables and settings;
 Tables of defects.

 
Servo fields are necessary for operation of a servo system used by the driving assembly of magnetic heads in a HDD; they serve for heads’ positioning and keeping them precisely over a defined track. Servo fields are recorded during the manufacturing process to an already assembled HDA through special service openings in its case. The openings are subsequently closed with sticky labels that read: Warning! DO…

Introduction
Brief architecture description, the main problems of modern hard disk drives, methods of HDD servicing and repair of simple malfunctions, SMART, passwords. The article is intended for data recovery specialists, technicians servicing computer equipment, network administrators and experienced users.

Drive construction
 A drive consists of a mechanical part – head-and-disk assembly (HDA) and a printed circuit board (PCB). HDA acts as a case for all mechanical parts of a hard drive and contains one more chip performing the functions of a preamplifier/commutator. A PCB consists of several chips which control the mechanical parts, encode/decode data on magnetic surfaces and transfer the data through an external interface. PCBs are located outside HDA, in its lower part as a rule. In…

Random Notes and Ideas For Data Recovery

1. Drive goes to sleep, replace the board live

2. Partitions start on Cylinder Boundaries

3. Hard Drives have a Safe Mode

4. You can fix LaCie problems with a Mac mounting them in the system

5. Drives that you plug in that cause windows to Crash – Use Ubuntu to Read Files

6. When problems with MFT then retry smaller blocks

7. If drive parts are good then rewriting the SA area is the part that needs repairing

8. SA Code can be replaced to do data destruction or encryption

9. If you are thinking of a hard drive as 0’s 1’s then you are wrong. The equipment interprets signals to make

…

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 as a donor drive. Head 0 is the bottom head and could be…

Slide 4500:  Doing a Platter Swap for a Single Platter

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

Just move the…

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 area to work on with as little dust floating around as possible.
…