Cable Noise Interference; Load/Unload; Start/Stop Cycles; Preventive Maintenance - Hitachi HDS723020BLA642 Specifications

Reliability
6.4
6.4.1 Data integrity
No more than one sector is lost at Power loss condition during the write operation when the write cache option is
disabled. If the write cache option is active, the data in write cache will be lost. To prevent the loss of customer
data, it is recommended that the last write access before power off be issued after setting the write cache off.
6.4.2

Cable noise interference

To avoid any degradation of performance throughput or error rate when the interface cable is routed on top or
comes in contact with the HDA assembly, the drive must be grounded electrically to the system frame by four
screws. The common mode noise or voltage level difference between the system frame and power cable ground
or AT interface cable ground should be in the allowable level specified in the power requirement section.
6.4.3

Load/Unload

The product supports a minimum of 300,000 normal load/unloads in a 40° C environment.
Load/unload is invoked by transition of the HDD's power mode.
Idle <-> unload idle
Idle <-> Low rpm idle*
*Note: Low rpm idle mode is supported on specific drive PN, only.
6.4.4

Start/stop cycles

The drive withstands a minimum of 50,000 start/stop cycles in a 40° C environment and a minimum of 10,000
start/stop cycles in extreme temperature or humidity within the operating range. .
6.4.5

Preventive maintenance

None
6.4.6

Data reliability

Probability of not recovering data is 1 in 10
LDPC on the fly/ offline data correction
 576 bit LDPC in 512 byte format
 This implementation recovers maximum 300 bits single burst error by on the fly correction and
maximum 425 bits single burst error by offline correction

6.4.7

Required Power-Off Sequence

The required BIOS sequence for removing power from the drive is as follows:
Step 1: Issue one of the following commands.
Standby
Standby immediate
Sleep
Note: Do not use the Flush Cache command for the power off sequence because this command does not
invoke Unload
Step 2: Wait until the Command Complete status is returned. In a typical case 350 ms are required for the
command to finish completion; however, the BIOS time out value needs to be 30 seconds considering error
recovery time.
Step 3: Terminate power to HDD.
14
bits read,
Hitachi hard disk drive specifications
33