 |
Home >Data Recovery Glossary |
Data Recovery Glossary
Base-Knowledge and glossary of data recovery and data recovery tools.
General Hard Drive Concepts:
General Data Recovery Concepts:
1. General Hard Drive Concepts
1.1 Start Chart
 
1.2 ROM
Stored the head map, PCB circuit, firmware address information.
27 series is Read-Only.
1.3 Servo Information
What is Servo?
Modern hard disks use actuators to position the heads on the surface of the hard disk's platters.The device is controlled rely on some special codes to do something. measuring the result, seeing how far off the device is from its target, making an adjustment, and repeating. This enables the device to reach its target intelligently . They are read by the heads and fed back to the actuator control logic to guide the actuator to the correct track. By putting different codes on each track of the disk, the actuator can always figure out which track it is looking at.
Embedded Servo
This servo technique intersperses servo information with data across the entire surface of all of the hard disk platter surfaces. The servo codes are written to the disk surfaces at the time the hard disk is manufactured. Special, complex and expensive equipment machines that do this are called Servo writers.
1.4 Firmware Components
What is Firmware?
Since Modern hard disk have microprocessors, they also have internal "software" that runs them.These programs make the drive work. Of course this isn't really software in the conventional sense. Those instructions are embedded into read-only memory, this code is similar with the system BIOS.
Firmware Structure
Most Firmware were stored in some sectors called Service Area (SA). Data Modules / Management Modules / Techno Modules.
1.5 Boot Sector
What is MBR?
Short for Master Boot Record, a small program that is executed when a computer boots up.
Typically, the MBR resides on the first sector of the hard disk. The program begins the boot process by looking up the partition table to determine which partition to use for booting. It then transfers program control to the boot sector of that partition, which continues the boot process.
DPT
EMBR
Extended Master Boot Record (EMBR), is a logical partition under the drive partitioning system. In that system, when one (and only one) partition record entry in the (MBR) is designated an "extended partition".
That partition can be subdivided into a number of logical drives. The actual structure of that extended partition is described by one or more EBRs, which are located inside the extended partition.
|
