INSIDE HARD DRIVE SYSTEM AREA

What is inside hard drive System Area?

Categories of System Area Info:

1. Smart Data 
2. System Logs 
3. Serial Number 
4. Model Numbers 
5. P-List (Primary Defects List –  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. Zone Tables
9. Servo Parameters

10. Specific Tables like RRO – (recalibrate repeatable run-out and head offsets) 
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 for drive – possible encrypted info.

System Area or System info notes:

• Usually there are two or more copies on different platters of the drive
•  Most of the time system info is on the Outer Tracks – Extreme Outer Edge
•  If info is corrupt it can be copied from the second one to make the drive operable
•  System Log Info can be written here
•  SA – Not Uniformed or standard in any way
•  Completely different per drive and per drive family
•  Can sometimes be copied from similar drives or drive families

using special tools

•  The smaller the amount of data stored in the SA, the more likely it is to replace with parts, Printed Circuit Boards and heads.

The System Area is made of UBA Modules (Utility Block Addressing) which are sector blocks logically grouped together that contain a specific MODULE. Each UBA block might be different per a drive manufacturer. The UBA might be Smart Data on one drive and a different type of data on another drive. The UBA area is inaccessible over the standard interface. Most of the commands to talk to the UBA modules are vendor specific and which is generally not made publically available. 
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 Lists – sector relocation table) The G-List is where the bad blocks that your drive has on a daily basis are stored. 
Since the P-List is done at manufacturing time that list is never suppose to change. There is a very important reason to know about both lists in a low level recovery. 
This is a short explanation what can case “clicking noise” at the boot time. 

Another reason for “clicking noise” is Physical Sector Damage