Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
160
- IGRA (Ignore Reassigned LBA) bit works in conjunction with the RC bit (Mode Page 01h, byte 2, bit 4).The main
purpose of this bit is to avoid undesirable read processing time delays due to reassigned LBA processing for
continuous data availability requirements such as Audio Visual applications. If IGRA is set to one and RC is set
to one, out-of-line reassigned LBAs will not be processed. If IGRA is set to one and RC is set to zero, or if IGRA
is set to zero, reassigned LBAs will be processed normally.
- AVERP (AV ERP Mode) bit is set to one in order to specify maximum retry counts during Read DRP. When
AVERP bit is set to one, the maximum retry counts for read operations is specified by Read Retry Count (Mode
Page 1 Byte 3). AVERP bit is set to zero to specify that the drive shall process read DRP up to the default
maximum retry count when Read Retry Count is set to a non-zero value.
- OCT(Overall Command Timer) controls the maximum command execution time, from receipt by the drive until
status is returned. If the command is unable to complete in the specified amount of time, it will be aborted with
Check Condition status, Aborted Command sense key. The Overall Command Timer does not alter the
behavior of the Command Aging Limit or Recovery Time Limit. Each unit of this timer is 50 milliseconds. Setting
the value to zero disable the feature.
- Temperature Threshold Temperature Threshold specifies the threshold value in degrees Celsius for the
thermal sensor Information Exception Warning; the reporting of which is controlled by Mode Page 0x1C. A value
of 0 selects the default value (85 degrees Celsius).
- Command Aging Limit This value controls the maximum time a command should wait in the command queue
when the CAEN bit is set. Each unit of this timer is 50ms.
- Read Reporting Threshold specifies the recovery step that must be exceeded to report recovered data errors
during read operations when PER=1.For example, if the Read Reporting Threshold is set to 22, recovered read
errors will be reported starting at recovery step 23
- Write Reporting Threshold specifies the recovery step that must be exceeded to report recovered data errors
during write operations when PER=1.For example, if the Write Reporting Threshold is set to 20, recovered write
errors will be reported starting at recovery step 21.
- DRRT (Disable Restore Reassign Target) bit disables the reading and restoration of the target LBA during a
Reassign Blocks command. If the DRRT bit is zero, the reassign command attempts to restore the target LBA's
data. If the data cannot be restored, the target LBA is reassigned and written with a data pattern of all 00s. If the
DRRT bit is one, no attempt is made to restore the target LBA.
- FFMT (Fast Format Enable) bit allows the formatting of the drive without any writes to the customer media. All
format operations are allowed including changing block sizes and manipulating defects. The drive will operate
normally after a fast format with the following caveat: since no data is written to any customer data blocks as a
result of a Fast Format operation, there is a possibility that a read attempt to any particular block (without having
previously written to that block) will result in an unrecoverable data error. This will most likely happen if the block
size is changed as every LBA will contain data of an incorrect length and apparently an incorrect starting point.
It is also possible to generate an uncorrectable data error without changing block sizes if the defect list is
shortened and previously bad blocks become visible in the customer address space. Of course ALL DATA ON
THE DRIVE WILL BE LOST as the result of any format operation and so any attempt to read blocks which have
not been written to will result in unpredictable behavior.
- FCERT (Format Certification) bit determines whether the certification step will be performed during a Format
Unit command. FCERT bit set to 0 disables certification. FCERT bit set to 1 enables the certification step.