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Hard Disk Details(4)

November 27th, 2008

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 for drive – possible encrypted info.

System Area or System info notes
1.    Usually there are two or more copies on different platters of the drive
2.    Most of the time system info is on the Outer Tracks – Extreme Outer Edge
3.    If info is corrupt it can be copied from the second one to make the drive operable
4.    System Log Info can be written here
5.    SA – Not Uniformed or standard in any way,
6.    Completely different per drive and per drive family
7.    Can sometimes be copied from similar drives or drive families using special tools
8.    The smaller the amount of data stored in the SA, the more likely it is to replace with parts, PCB’s and heads.
**** PCB = Printed Circuit Boards

Slide 1816: 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. There are certain pieces of hardware that can be used to communicate with this area such as the PC3000.

For example: In the UBA 1 Area it could be a Bad Block List.  As larger drives have been created there has been a need for larger bad block areas.  So this might be expanded from two sectors in a previous drive to three sectors in a newer drive. But the firmware for the drive can still refer to each of them as UBA 1 and does not have to have any changes made to the code in the firmware regardless of the size change.

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